CFR NPRM

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[Federal Register: June 10, 1975]
[Page 24802]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 21, 23, 25, 27, 29, 31, 33, and 35
[Docket No. 14685; Notice No. 75-26]


Airworthiness Review Program, Notice No. 7; Airframe Proposals

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AGENCY: Federal Aviation Administration, DOT

ACTION: Proposed Rules

SUMMARY:
The Federal Aviation administration is considering amending Parts 23, 25, 27, and 29 of the Federal Aviation Regulations to update and improve the airframe and crashworthiness standards applicable to the type certification of aircraft, and to make certain related changes in the operating rules contained in Part 121.

DATES: Comments on this notice must be received on or before September 8, 1975.


SUPPLEMENTARY INFORMATION:
This is the seventh in a series of Notices of Proposed rule Making issued, or to be issued, as a part of the First Biennial Airworthiness Review Program. Notice No. 74-33 (39 FR 36095; October 11, 1974) was the first. Amendments 21-43, 23-16, and 25-37, issued on December 31, 1974 (40 FR 2576; January 14, 1975) pursuant to that notice, incorporated certain form number and clarifying revisions into the Federal Aviation Regulations.
In addition to Notice No. 74-33, the following Airworthiness Review Program Notices of Proposed Rule Making have been issued:

Airworthiness Review Program Notice No.
Notice No.
Federal Register Citation
2
75-10
(40 FR 10802; Mar. 7, 1975).
3
75-19
(40 FR 21866; May 19, 1975).
4
75-20
(40 FR 22110; May 20, 1975).
5
75-23
(40 FR 23047; May 27, 1975).
6
75-25
(40 FR 24663; June 9, 1975).

Interested persons, including the general public, manufacturers and users of aircraft and their components, both foreign and domestic, and foreign airworthiness authorities, are invited to participate in this proposed rulemaking by submitting such written data, views, or arguments as they may desire. Comments relating to any significant environmental or economic impact that might result because of the adoption of the proposals contained herein may also be submitted. Comments should identify this regulatory docket or notice number (Docket No. 14685; Notice No. 75-26) and be submitted in duplicate to: Federal Aviation Administration, Office of Chief Counsel, Attention: Rules Docket, AGC-24, 800 Independence Avenue, SW, Washington, D.C. 20591. All communications received on or before September 8, 1975, will be considered by the Administrator before taking action on the proposed rules. However, interested persons are urged to submit their comments as early as possible to facilitate rapid resolution of any issues raised. The proposals contained in this notice may be changed in the light of comments received. All comments submitted will be available in the Rules Docket for examination by interested persons.
On February 12, 1974, the FAA issued an invitation to all interested persons to submit proposals for consideration during the First Biennial Airworthiness Regulations Review (see Notice 74-5; 39 FR 5785; February 15, 1974). In that notice, the FAA announced that it would make available for comment by interested persons a compilation of proposals that were to be given further consideration as possible agenda items for the First Biennial Airworthiness Review Conference. On May 22, 1974, the FAA issued an announcement of the availability of the Compilation of Proposals containing over 1000 submissions by the FAA and interested persons, and invited all interested persons to submit comments on the proposals it contained (see Notice 74-5A; 39 FR 18662; May 29, 1974).
In response to that invitation for comments, the FAA received over 4900 individual comments contained in 74 submissions. Based on those comments and on the Compilation of Proposals, the FAA prepared a number of working documents, for the Airworthiness Review Conference held in Washington, D.C., on December 2-11, 1974. The FAA distributed those documents to all persons who had participated in the Airworthiness Review Program and to all other interested persons who requested them (see Notice 74-5B; 39 FR 36594; October 11, 1974).
For reasons given in Notice 74-5B, not all of the proposals contained in the Compilation were included in the agenda for the conference. However, the proposals not included in the agenda were listed in a conference workbook titled "Proposals Not in Agenda." In general, Notice 75-10 deals with the proposals identified as "Items for Notice" in that workbook.
On November 25, 1974, the FAA issued a Notice of Conference that set forth the schedule for the conference and invited all interested persons to attend the conference (see Notice 74-5C, 39 FR 41319; November 26, 1974).
The Airworthiness Review Conference was attended by over 586 individuals including representative of 22 foreign airworthiness authorities as well as aircraft manufacturers and users. Except for the opening and closing plenary sessions of the conference, one or more committees discussed agenda items during conference working hours. Summaries were given by the FAA Committee Chairman at the close of discussions on each agenda item. Persons present were given an opportunity to correct those oral summaries. Those summaries were transcribed with editorial revisions and combined with an attendee list for the conference as well as with transcripts of certain plenary session speeches and were distributed in accordance with a Notice of Availability issued February 4, 1975 (see Notice 74-5D; FR 5810; February 7, 1975).
In general this notice deals with the proposals that were contained in the Committee workbooks titled "Committee III - Airframe (Large Airplanes)" and "Committee III - Airframe (Small Aircraft and Rotorcraft)". These workbooks contained the proposals discussed by the two Airframe Committees (Committee III - Airframe (Large Airplanes) Part 1 and Committee III Part 2 - Airframe (Rotorcraft and Small Airplanes)) at the Airworthiness Review Conference as well as written comments that were received for those proposals in response to Notice 74-5A. Another conference working document used was the Agenda for the Airworthiness Review Conference. That document, in addition to providing general information relating to the conference, included detailed information on how the proposals were grouped into agenda items, and the scheduling of those items for discussion. Both the workbooks and the agenda were updated and corrected by a supplemental working document distributed prior to and at the conference to participating individuals as well as to other interested persons. These workbooks along with the committee discussions and written information submitted by conference attendees has provided the basis upon which the FAA has developed this notice.
A number of proposals contained in this notice were not included in the Committee III workbooks. They are directly related to the proposals in the workbooks and are included for the sake of clarity, consistency, and comprehensiveness.
A number of proposals contained in the Committee III workbooks are not included in this notice. These proposals fall into two general categories - (1) those proposals which are being deferred to a later notice or to the next Airworthiness or Operations Review, and (2) those proposals withdrawn by their proponent.
Appendix I of this notice lists the proposals in the first category, and Appendix II of this notice lists those in the second. In general it is felt by the FAA that the groups of proposals in Appendix I that will appear in the next Airworthiness or Operations Review, unless withdrawn by their proponent, have sufficient merit to warrant further consideration, but because of the complexity of the proposal, the need for additional data, or the operational character of the proposal, further consideration within this Airworthiness Review Program is not feasible. The other group of proposals included in Appendix I are being deferred to be dealt with in a later notice to be issued as a part of this Airworthiness Review Program. A number of these proposals may be deferred or removed by the FAA from consideration in the Airworthiness Review Program in that later notice.
The FAA believes that the airworthiness standards should, to the extent practical, be consistent throughout the aircraft certification parts (Parts 23, 25, 27, and 29). Therefore, the FAA has attempted within the time frame of this Airworthiness Review Program, to make consistent and parallel proposals, where appropriate, for each of the certification parts.
To avoid unnecessary repetition, in a number of instances the proposals developed for purposes of consistency are not set forth in their entirety if those proposals are substantively identical to another proposal in this notice. A short-form proposal referring to a proposal that is expressly set forth in this notice is used. Where a short-form proposal is used, however, there may be a need, if the proposal is to be adopted as a final rule, to change paragraph designations, cross references, or aircraft terminology (e.g., "airplane" to "rotorcraft", or vice versa) from that used in the referenced express proposal.
The FAA recognizes that there may exist additional instances in which a proposed rule change prescribed in this notice as expressly applying only to certain parts of the Federal Aviation Regulations should more appropriately apply to additional parts as well. Therefore, with respect to each proposal in this notice relating to Parts 23, 25, 27, or 29 of the Federal Aviation Regulations for which similar proposals do not exist for all of those parts, comments are solicited from all interested persons with respect to the applicability of that proposal (and its stated explanation) to those parts for which the proposal has not been expressly presented. Such comments received in response to this notice will either be dealt with as a part of the 1974-1975 Airworthiness Review Program or be considered as a part of the next Biennial Airworthiness Review.
For convenience, each proposal in this notice is numbered separately. The FAA requests that interested persons, when submitting comments, refer to proposals by these numbers, or by the sections to which they relate. Each proposal contains, or references a proposal that contains, a reference to the Airworthiness Review Program proposal number, section, and agenda item to which that proposal relates, and to the part of Committee III in which the proposal was discussed. Comments on this notice should not refer to the Airworthiness Review Program proposal numbers or section numbers without also referring to the corresponding proposal numbers as set forth in this notice. Each proposal in this notice is provided with an explanation. In addition, to avoid confusion several of the proposals in this notice reference proposals in Notice 75-10 that deal with the same regulatory provisions. Several explanations deal with comments received in response to Notice 74-5A: however, all comments submitted in response to Notice 74-5A or submitted for the Airworthiness Review Conference, dealing with proposals contained in this notice, should be resubmitted if it is desired that they be considered as a part of this rulemaking action.
This amendment is proposed under the authority of sections 313(a), 601, 603, and 604 of the Federal Aviation Act of 1958 (49 U.S.C. 1354(a), 1421, 1423, and 1424) and of section 6(c) of the Department of Transportation Act (49 U.S.C 1855(c)).

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The Proposed Amendment:
In consideration of the foregoing, it is proposed to amend Parts 23, 25, 27, 29, and 121 of the Federal Aviation Regulations as follows:

PART 23 - AIRWORTHINESS STANDARDS: NORMAL, UTILITY, AND ACROBATIC CATEGORY AIRPLANES

7-1. By revising Sec. 23.345(c); and adding a new Sec. 23.345(f) to read as follows:

Sec. 23.345 High lift devices.
* * * * *
(c) In designing the flaps and supporting structures, the following must be accounted for: (1) A head-on gust having a velocity of 25 feet per second (EAS). (2) The slipstream effects specified in sec. 23.457(b).
* * * * *
(f) The airplane must be designed for landing at the maximum takeoff weight with a maneuvering load factor of 1.5g and the flaps and similar high lift devices in the landing configuration.

Explanation. The current rule requires accounting for propeller slipstream effects in the design of flaps and supporting structures. The proposal for Sec. 23.345(c) would provide for consideration of the effects of a head-on gust to provide a more realistic design condition.
For the proposed addition of a new paragraph (f), see the proposal for Sec. 25.345(d).
Ref. Proposal No. 615; Sec. 23.345(c); Part 2 - Agenda Item C-14.

7-2 By revising the table in sec. 23.561(b)(2) to read as follows:

Sec. 23.561 General.
* * * * *
(b) * * *
(2) * * *

Ultimate Inertia Forces
Normal and Utility CategoriesAcrobatic Category
Upward
3.0g
4.5g
Forward
9.0g
9.0g
Sideward
1.5g
1.5g
Rearward
3.0g
3.0g

* * * * *

Explanation. This proposal is related to the proposal for Sec. 23.785. Investigations of recent general aviation aircraft accidents have indicated a need to improve the seat attachment requirements. The purpose of this proposal is to provide rearward acceleration standards to which seat attachments would be designed.
Ref. Proposal No. 134; Sec. 23.561; Part 2 - Agenda Item D-18.

Sec. 23.603 [Amended]
7-3. By adding a new Sec. 23.603(a)(3) that would be substantively identical to the proposed new Sec. 25.603(c).

Sec. 23.605 [Amended]
7-4. By redesignating Sec. 23.605 as Sec. 23.605(a) and adding a new Sec. 23.605(b) that would be substantively identical to the proposed new Sec. 25.605(b).

7-5. By revising the lead in of Sec. 23.613(c) to read as follows:

Sec. 23.613 Material strength properties and design values.
* * * * *
(c) The design values must be those contained in the following publications (obtainable from the Superintendent of Documents, Government Printing Office, Washington, D.C. 20402) or other values approved by the Administrator:
* * * * *

Explanation. The proposal would revise Sec. 23.613 to allow industry to use design values other than those presently provided for in the rule.
Ref. Proposal No. 82; Sec. 23.613; Part 2 - Agenda Item D-19.

7-6. By revising Sec. 23.629 to read as follows:

Sec. 23.629 Flutter.
(a) It must be shown by any one of the methods specified in paragraphs (b), (c), or (d) of this section that the airplane is free from flutter, control reversal, and divergence for any condition of operation within the limit V-n envelope, and at all speeds up to the speed specified for the selected method. In addition -
(1) Adequate tolerances must be established for quantities which affect flutter, including speed, damping, mass balance, and control system stiffness; and
(2) The natural frequencies of main structural components must be determined by vibration tests.
(b) A rational analysis may be used to show that the airplane is free from flutter, control reversal, and divergence if stability is shown for all speeds up to 1.2 VD.
(c) Flight flutter tests may be used to show that the airplane is free from flutter, control reversal, and divergence if it is shown by these tests that -
(1) Proper and adequate attempts to induce flutter have been made within the speed range up to VD;
(2) The vibratory response of the structure during the test indicates freedom from flutter;
(3) A proper margin of damping exists at VD; and
(4) There is no large and rapid reduction in damping as VD is approached.
(d) Compliance with the rigidity and mass balance criteria (pages 4-12) in Airframe and Equipment Engineering Report No. 45 (as corrected) "Simplified Flutter Prevention Criteria" (published by the Federal Aviation Administration) may be accomplished to show that the airplane is free form flutter, control reversal, or divergence if -
(1) VD for the airplane is less than 260 knots (EAS) at altitudes below 14,000 feet and less than Mach 0.6 at altitudes at and above 14,000 feet;
(2) The wing and aileron flutter prevention criteria, as represented by the wing torsional stiffness and aileron balance criteria, are limited in use to airplanes without large mass concentrations (such as engines, floats, or fuel tanks in outer wing panels) along the wing span; and
(3) The airplane -
(i) Does not have a T-tail or boom tail;
(ii) Does not have unusual mass distributions or other unconventional design features that affect the applicability of the criteria; and
(iii) Have fixed-fin and fixed-stabilizer surfaces.
(e) For multiengine turbopropeller powered airplanes, the dynamic evaluation must include -
(1) Whirl mode degree of freedom which takes into account the stability of the plane of rotation of the propeller and significant elastic, inertial, and aerodynamic forces; and
(2) Engine-propeller-nacelle stiffness and damping variations appropriate to the particular configuration.
(f) The airplane must be free from flutter, control reversal, and divergence up to VD/MD after the failure malfunction, or disconnection of any single element in the primary flight control system, any tab control system, or any flutter damper.

Explanation. Part 23 airplanes are now operating at higher airspeeds than in the past. The service experience of these current high speed designs indicates a need for upgrading the type certification flutter requirements. This proposal would establish the needed requirements.
Ref. Proposal Nos. 86, 623; Sec. 23.629, Sec. 23.629(a); Part 2 - Agenda Item D-21.

7-7. By adding a new Sec. 23.677(d) to read as follows:

Sec. 23.677 Trim systems.
* * * * *
(d) If the horizontal stabilizer is used for providing longitudinal trim and is power boosted or power operated, an aural warning device must be installed that provides a distinctive continuous warning whenever -
(1) The horizontal stabilizer is in transit due to trim system operation; or
(2) The power or thrust controls are in a position for takeoff with the trim set in a position outside the approved range for takeoff.

Explanation. The FAA believes that there is a need for "trim-in-motion" indication and "takeoff out-of-trim" warning for certain longitudinal trim systems. The proposal would change the trim system requirements to require aural warning to the pilot when horizontal stabilizer trim is in motion and also when the power or thrust controls are advanced to the takeoff position with the stabilizer trim set in a position outside the approved range for takeoff.
Ref. Proposal No. 625; Sec. 23.677(d); Part 2 - Agenda Item E-22.

Sec. 23.701 [Amended]
7-8. By amending Sec. 23.701(a) in a manner substantively identical to that proposed for Sec. 25.701(a).

Sec. 23.723 [Amended]
7-9. By amending Sec. 23.723(a) in a manner substantively identical to that proposed for Sec. 25.723(a).

7-10. By revising Sec. 23.737 to read as follows:

Sec. 23.737 Skis.
(a) Each ski must be approved.
(b) The maximum limit load rating of each ski must equal or exceed the maximum limit load determined under the applicable ground load requirements of this part.
(c) Compliance with the shock absorption tests specified in Sec. 23.723 must be demonstrated with ski components installed.

Explanation. The purpose of this proposal is to require that shock absorption tests be conducted with ski components installed on the landing gear. Experience in the field has shown that ski installation approvals based on drop tests conducted with wheels and tires in lieu of skis has resulted in understrength installations.
Ref. Proposal No. 631; Sec. 23.737; Part 2 - Agenda Item F-26.

7-11. By adding a new Sec. 23.785(h) to read as follows:

Sec. 23.785 Seats and berths.
* * * * *
(h) Each seat track must be fitted with stops to prevent the seat from sliding off the track.

Explanation. The proposal would broaden Sec. 23.785 to include requirements to improve seat retention. Investigations of recent general aviation aircraft accidents have indicated a need to improve the seat retention requirements.
Ref. Proposal No. 94; Sec. 23.785; Part 2 - Agenda Item D-18.

7-12. By adding a new Sec. 23.853(e) to read as follows:

Sec. 23.853 Compartment interiors.
* * * * *
(e) Airplane materials located on the cabin side of the firewall must be self-extinguishing or be located at such a distance from the firewall, or otherwise protected, so that ignition will not occur if the firewall is subjected to a flame temperature of not less than 2000F for 15 minutes. For self-extinguishing materials a vertical self-extinguishing test must be conducted in accordance with the applicable portions of Appendix F of Part 25 or an equivalent method approved by the Administrator. The average burn length of the material may not exceed 6 inches and the average flame time after removal of the flame source may not exceed 15 seconds. Drippings from the material test specimen may not continue to flame for more than an average of 3 seconds after failing.

Explanation. There have been instances where cabin upholstery has been ignited by engine fires even though the flame did not penetrate the firewall. This proposal would broaden Sec. 23.853 to require materials located on or adjacent to the cabin side of the firewall to be self-extinguishing or otherwise protected to prevent fire within the cabin due to engine fire.
Ref. Proposal No. 637; Sec. 23.853(e); Part 2 - Agenda Item H-32.

7-13. By adding a new Sec. 23.863 to read as follows:

Sec. 23.863 Flammable fluid fire protection.
(a) In each area where flammable fluids or vapors might escape by leakage of a fluid system, there must be means to minimize the probability of ignition of the fluids and vapors, and the resultant hazards if ignition does occur.
(b) Compliance with paragraph (a) of this section must be shown by analysis or tests, and the following factors must be considered:
(1) Possible sources and paths of fluid leakage, and means of detecting leakage.
(2) Flammability characteristics of fluids, including effects of any combustible or absorbing materials.
(3) Possible ignition sources, including electrical faults, overheating of equipment, and malfunctioning of protective devices.
(4) Means available for controlling or extinguishing a fire, such as stopping flow of fluids, shutting down equipment, fireproof containment, or use of extinguishing agents.
(5) Ability of airplane components that are critical to safety of flight to withstand fire and heat.
(c) If action by the flight crew is required to prevent or counteract a fluid fire (e.g. equipment shutdown or actuation of a fire extinguisher) quick acting means must be provided to alert the crew.
(d) Each area where flammable fluids or vapors might escape by leakage of a fluid system must be identified and defined.

Explanation. The first purpose of the proposal is to require protection from a flammable fluid or vapor fire. Investigations of two accidents disclosed evidence of in-flight fires outside the confines of the engine compartment and the containing firewall caused by leakage of flammable fluids. The proposal is directed at minimizing the probability of such occurrences and their severity if they do occur.
The second purpose is to require that the areas where flammable fluids or vapors could escape by the leakage of a fluid system be identified and defined. The proposal to require that the information be placed in a maintenance manual will be dealt with in a later notice as a part of this Airworthiness Review Program.
Ref. Proposal Nos. 263, 638, 735, 915, 1108; Sec. 23.863, Sec. 25.863(a), Sec. 25.863(d), Sec. 27.863, Sec. 29.863(c); Part 1 - Agenda Item N-80, Part 2 - Agenda Items B-109, H-33.

7-14. By revising Sec. 23.1307(a) to read as follows:

Sec. 23.1307 Miscellaneous equipment.
(a) There must be an approved seat for each occupant.
* * * * *

Explanation. The proposal would add the requirement for an approved seat for each occupant to Sec. 23.1307. This requirement would eliminate questions as to maximum seating capacity and compliance with the emergency exit requirements.
Section 23.785(g) requires that each occupant be provided with a safety belt.
Ref. Proposal No. 679; Sec. 23.1307(a); Part 2 - Agenda Item H-34.

7-15. By revising Sec. 23.1413(a) to read as follows:

Sec. 23.1413 Safety belts and harnesses.
(a) The rated strength of each safety belt and harness may not be less than the higher of that corresponding to -
(1) The highest loads expected in service under any loading condition; or
(2) The ultimate load factors specified in sec. 23.561(b). The loads computed for the seat belt and harness must take into consideration the geometric relationships that would exist during normal use.
* * * * *

Explanation. This proposal would broaden the rated strength requirements for safety belts and harnesses to include consideration of expected service loads as well as the ultimate load factors specified in Sec. 23.561(b).
Ref. Proposal No. 698; Sec. 23.1413(a); Committee V - Agenda Item J-57.

7-16. By adding a new Sec. 23.1416 to read as follows:

Sec. 23.1416 Pneumatic de-icer boot system.
If certification with ice protection provisions is desired and a pneumatic de-icer boot system is installed -
(a) The system must meet the requirements specified in Sec. 23.1419;
(b) The system and its components must be designed to perform their intended function under any foreseeable system operating temperature or pressure;
(c) Means must be provided to indicate to the flight crew the pneumatic de-icer boot system pressure; and
(d) Means to indicate to the flight crew that the pneumatic de-icer boot system is functioning normally must be provided.

Explanation. This proposal would establish specific standard for pneumatic de-icer boot systems. The FAA believes that the present rules, concerning ice protection in general do not adequately cover these systems.
Ref. Proposal No. 689, 895; Sec. 23.1416(a), (b), (c), Sec. 25.1416; Part 2 - Agenda Item H-35, Part I - Agenda Item O-87.

PART 25 - AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES

Sec. 25.305 [Amended]
7-17. By adding at the end of Sec. 25.305(d) a sentence that reads:
"In the absence of a more rational criteria, the continuous gust design criteria of Appendix G of this part must be used to establish the dynamic response of the airplane to vertical and lateral continuous turbulence."

Explanation. The present rule requires that the dynamic response of the airplane to vertical and lateral continuous turbulence be taken into account in determining structural strength and deformation, but does not contain criteria for establishing that information. This proposal, in conjunction with the proposed new Appendix G for Part 25, would provide for the use of a realistic criteria, and would allow the use of other criteria, if shown to be more rational than that proposed in Appendix G.
Ref. Proposal No. 1046; Sec. 25.305; Part 1 - Agenda Item A-2.

7-18. By deleting Sec. 25.331(c)(3) and marking it "[Reserved]", revising Secs. 25.331(c)(1) and (c)(2), and adding a sentence to the end of Sec. 25.331(a)(4) to read as follows:

Sec. 25.331 General.
(a) * * *
(4) * * *. The in-trim and out-of-trim flight conditions specified in Sec. 25.255 must be considered.
* * * * *
(c) * * *
(1) Maximum elevator displacement at VA. The airplane is assumed to be flying in steady level flight (point A1, Sec. 25.333(b)) and, except as limited by pilot effort in accordance with Sec. 25.397(b), the pitching control is suddenly moved to obtain extreme positive pitching (nose up). The dynamic response of the airplane must be taken into account in determining the tail load. Airplane loads which occur subsequent to the normal acceleration at the center of gravity exceeding the maximum positive limit maneuvering load factor, n, need not be considered.
(2) Specified control displacement. A checked maneuver, based on a rational pitching control motion vs. time profile, must be established in which the design limit load factor specified in Sec. 25.337 will not be exceeded. Unless lesser values could not be exceeded, the airplane response must result in pitching accelerations not less than the following:
(i) A positive pitching acceleration (nose up) is assumed to be reached concurrently with the airplane load factor of 1.0 (Points A1 to D1 Sec. 25.333(b)). This positive acceleration must be equal to at least



where--
n is the positive load factor at the speed under consideration; and
V is the airplane equivalent speed in knots.
(ii) A negative pitching acceleration (nose down) is assumed to be reached concurrently with the positive maneuvering load factor (points A1 to D1, Sec. 25.383(b)). This negative pitching acceleration must be equal to at least



where -
n is the positive load factor at the speed under consideration; and
V is the airplane equivalent speed in knots.
* * * * *

Explanation. Service experience on jet transport category airplanes indicates that maneuvers within the design envelope while in out-of-trim configurations occur often enough to warrant investigation, as proposed in sec. 25.331(a)(4).
Paragraph (c)(1) of this section would be amended to clarify that calculations need not be continued beyond that point in the load factor time-history at which the maximum positive limit maneuvering load factor is reached. Proposed paragraph (c)(2) would combine the requirements specified in existing paragraphs (c)(2) and (c)(3) and would eliminate duplication. Proposed paragraph (c)(2) would require the applicant to establish a pitching control motion vs. time profile to obtain the airplane's pitching accelerations.
Proposed Sec. 25.331(a)(4) references Sec. 25.255 which is being proposed in Notice No. 6 (40 FR 29663, June 9, 1975). Proposed Sec. 25.255 reads as follows:
From an initial condition with the airplane trimmed at cruise speeds up to VMO/MMO, the airplane must have satisfactory maneuvering stability and controllability with the degree of out-of-trim in both the airplane nose up and nose down directions, which results from a three-second movement of the primary longitudinal trim system at its normal rate with no aerodynamic load, or the maximum mistrim that can be sustained by the autopilot while maintaining level flight in the high speed cruising condition, whichever is greater. In this out-of-trim condition:
(a) The stock force per g curve must have a positive slope between 1g and +.5 g's at speeds up to VFC/MFC and there may not be reversal of the primary longitudinal control force at speeds up to VDF/MDF except that lesser acceleration values may be used at altitudes and speeds where buffet envelopes are established in accordance with Sec. 25.231(e).
(b) Compliance with the provisions of paragraph (a) of this section must be demonstrated in flight over the normal acceleration range of -
(1) -1g to +0.5g's; or
(2) 0g to 2.0g's, and extrapolating by an acceptable method to -1g and +2.5g's.
(c) If the procedure set forth in paragraph (b)(2) of this section is used to demonstrate compliance and marginal conditions exist during flight test with regard to reversal of primary longitudinal control force, flight tests must be accomplished from the normal acceleration at which a marginal condition is found to exist to the applicable limit specified in paragraph (a) of this section.
(d) It must be possible from an overspeed condition at VDF/MDF to produce at least 1.5g's for recovery by applying not more than 125 pounds of longitudinal control force using either the primary longitudinal control alone or the primary longitudinal control and the longitudinal trim system. If the longitudinal trim is used to assist in producing the required load factor it must be shown at VDF/MDF that the longitudinal trim can be actuated in the airplane nose up direction with the primary surface loaded to correspond to the least of the following airplane nose up control forces:
(1) The maximum control forces expected in service as specified in Secs. 25.301 and 25.397.
(2) The control force required to produce 1.5g's.
(3) The control force corresponding to buffeting or other phenomena of such intensity that it is a strong deterrent to further application of primary longitudinal control force.
(f) Recovery from normal accelerations less than 1g must be accomplished without exceeding VDF/MDF.
Ref. Proposal Nos. 189, 1048, 1049; Sec. 25.331(a)(4), Sec. 25.331(c), Sec. 25.331(c)(2); Part 1 - Agenda Items B-5, B-6.

7-19. By adding a new Sec. 25.341(d) to read as follows:

Sec. 25.341 Gust loads.
* * * * *
(d) The empennage must be designed for the gust loadings and airspeeds specified in this section applied in any direction normal to the airplane flight path.

Explanation. The present regulations do not cover gusts that are not purely vertical or lateral. Design of the empennage should account for the possibility of gusts which are not purely vertical or lateral in direction.
Ref. Proposal No. 195; Sec. 25.351(c); Part 1 - Agenda Item B-10.

7-20. By deleting the words "as speed brakes" from the lead in of Sec. 25.345(c) and adding a new Sec. 25.345(d) to read as follows:

Sec. 25.345 High lift devices.
* * * * *
(d) The airplane must be designed for landing at the maximum takeoff weight with a maneuvering load factor of 1.5g and the flaps and similar high lift devices in the landing configuration.

Explanation. By deleting the qualifying phrase "as speed brakes" from paragraph (c), the proposal would require consideration of the use of flaps (and similar high lift devices) for purposes other than as speed brakes, since flaps and slats are currently also used to improve control of the airplane in en route conditions. In addition the practice of limiting flaps by airplane weight in addition to airplane speed has indicated a need to assure that adequate strength is provided for unusual landings at weights above the landing weight. The new paragraph (d) would provide an appropriate design condition for such situations.
Ref. Proposal No. 193; Sec. 25.345; Part 1 - Agenda Item B-9.

Sec. 25.351 [Amended]
7-21. By deleting the symbol "VA" in the lead in of Sec. 25.351(a) and replacing it with the symbol "VD".

Explanation. The proposal would extend the upper limit of the speed range specified in the current Sec. 25.351(a) from VA to VD. Loss of control of transport airplanes has occurred often enough to justify a requirement to design for consideration of higher speeds than are presently required.
Ref. Proposal Nos. 194, 1050; Sec. 25.351, Sec. 25.351(a); Part 1 - Agenda Item B-10.

7-22. By deleting the words "The limit engine torque" in sec. 25.361(a)(1) and replacing them with the words "A limit engine torque"; by deleting the words "The limit engine torque corresponding to maximum continuous power and propeller speed" in Sec. 25.361(a)(2) and replacing them with the words "A limit engine torque as specified in Sec. 25.361(c)"; by deleting the words "the limit engine torque" in sec. 25.361(a)(3) and replacing them with the words "a limit engine torque"; and by revising Sec. 25.361(b) and the lead in of Sec. 25.361(c) to read as follows:

Sec. 25.361 Engine torque.
* * * * *
(b) For turbine engine installations, the engine mounts and supporting structure must be designed to withstand each of the following:
(1) A limit engine torque load imposed by sudden engine stoppage due to malfunction or structural failure (such as compressor jamming).
(2) A limit engine torque load imposed by the maximum acceleration of the engine.
(c) The limit engine torque to be considered under paragraph (a)(2) of this section must be obtained by multiplying the mean torque for maximum continuous power by a factor of -
* * * * *

Explanation. Section 25.361(b) would be revised to redefine the limit engine torque load conditions to be considered for turbine engine installations. Section 25.361(c) would be revised to clarify that it only applies with respect to Sec. 25.361(a)(2). Other clarifying changes are also proposed.
Ref. Proposal No. 196; Sec. 25.361; Part 1 - Agenda Item C-11.

7-23. By revising Sec. 25.491, including its heading, to read as follows:

Sec. 25.491 Taxiing and takeoff run.
The airplane structure, including the landing gear, must be investigated for the dynamic loads resulting from the roughest runway and taxiway profiles to be expected in normal operation with the airplane in the most critical configuration.

Explanation. The proposal would clarify the present rule.
Ref. Proposal Nos. 205, 1054; Sec. 25.491; Part 1 - Agenda Item E-18.

7-24. By adding a new Sec. 25.499(e) to read as follows:

Sec. 25.499 Nose-wheel yaw.
* * * * *
(e) With the airplane at design ramp weight, and the nose gear in any steerable position, the combined application of full normal steering torque and a vertical force equal to the maximum static reaction on the nose gear must be considered in designing the nose gear, its attaching structure and the forward fuselage structure.

Explanation. This proposal would establish a needed requirement for nose gear loads due to steering.
Ref. Proposal No. 207; Sec. 25.499(e); Part 1 - Agenda Item E-21.

7-25. By adding a new Secs. 25.561(b)(3)(v) and (d) to read as follows:

Sec. 25.561 General.
* * * * *
(b) * * *
(3) * * *
(v) Rearward - 1.5g
* * * * *
(d) For airplanes with a passenger deck located below the main deck level, that may be occupied during takeoff or landing, the structure must be designed to give each lower deck occupant every reasonable chance of escaping serious injury in each of the following situations taking into account the distortion of the occupied cabin area that would occur and the dynamic loads that would be transmitted to the occupants:
(1) Landing at design landing weight on a paved runway with landing gear extended at an ultimate descent speed of 15 feet per second.
(2) Landing at design landing weight on a paved runway at an ultimate descent speed of 5 feet per second with any one or more landing gear legs not extended.
(3) Landing at nominal landing speeds and subsequent overruns and contact with an upgrade that results in -
(i) Nose and main landing gear separation; and
(ii) Settling of the airplane to the ground;
(iii) Critical airframe failure; and
(iv) Crushing of the lower fuselage structure.

Compliance with the provision of paragraphs (d)(1), (2), and (3) of this section may be shown by analysis if the analytical methods used have been shown to be reliable or the methods are sufficiently conservative to warrant their use. In addition, an upgrade/speed envelope must be established in showing compliance with paragraphs (a)(3)(iii) and (a)(3)(iv) of this section.

Explanation. This proposal is related to the proposals for Secs. 25.563, 25.807 and 25.813. The purpose of this proposal is to establish needed structural crashworthiness requirements for airplanes having a passenger deck located below the main deck level that may be occupied during takeoff and landing. It should be noted that this proposal does not include the reference to fuel system integrity which was initially suggested, since it is adequately covered under Secs. 25.721 and 25.963. The proposed amendment also would add a new rearward "g" survivability requirement to the existing upward, forward, sideward and downward requirements.
Ref. Proposal Nos. 209, 1056; Sec. 25.561, Sec. 25.561(a); Part 1 - Agenda Items F-23, L-67.

7-26. By redesignating Sec. 25.563 as Sec. 25.563(a) and by adding a new sec. 25.563(b) to read as follows:

Sec. 25.563 Structural ditching provisions.
* * * * *
(b) For airplanes with a passenger deck located below the main deck level that may be occupied during takeoff or landing, the following apply whether or not the airplane is to be approved for ditching:
(1) The strength of doors, the leakage of door seals in the lower deck, the strength of the fuselage taking into account probable pressures during ditching, and the means of evacuation of occupants from the lower deck must provide for the safety of lower deck occupants under planned and unplanned ditching conditions. Descent velocities shown to be probable for planned ditching conditions must be used in design but in no case may a planned descent velocity be less than three feet per second.
(2) Failure of doors, seals, and other structural parts of the lower fuselage under ditching conditions may not result in the occupants not having sufficient time to evacuate the lower deck compartments. Escape routes to places where occupants enter life rafts must be shown to be adequate for the occupant capacity of the lower deck.

Explanation. This proposal is related to the proposals for Secs. 25.561, 25.807 and 25.813. The purpose of this proposal is to establish needed structural ditching capability requirements of airplanes with a passenger deck located below the main deck level that may be occupied during takeoff and landing.
Ref. Proposal No. 1057; Sec. 25.563; Part 1 - Agenda item L-67.

7-27. By revising Sec. 25.571(c)(1) to read as follows:

Sec. 25.571 Fatigue evaluation of flight structure.
* * * * *
(c) * * *
(1) An ultimate maneuvering load factor equal to 80 percent of the design maneuvering load factor.
* * * * *

Explanation. The purpose of this proposal is to require that the ultimate maneuvering load factor for fail safe strength evaluation be 80 percent of the design maneuvering load factor instead of the current 2.0g at VC.
The current regulation was written with large transports in mind. The small jets which are being designed to Part 25 criteria have higher design maneuvering load factors than those of the large transports. The 80 percent factor is needed to make the regulation consistent regardless of the design maneuvering load factor used.
Ref. Proposal No. 1059; Sec. 25.571(c)(1); Part 1 - Agenda Item G-24.

7-28. By deleting the word "and" at the end of Sec. 25.603(a); by inserting a semicolon and the word "and" at the end of Sec. 25.603(b); and by adding a new Sec. 25.603(c) to read as follows:

Sec. 25.603 Materials.
* * * * *
(c) Be established to show that the materials will maintain their design properties throughout their service lives taking into consideration the environmental conditions expected in service.

Explanation. Aircraft are adversely affected by long-time exposure to the environment. The proposal would broaden Sec. 25.603 to require the applicant to show that the materials used in the structure will maintain their design properties throughout their service lives.
It should be noted that Notice No. 75-10 (40 FR 10809; March 7, 1975) contains a proposal to expand the coverage of this section.
Ref. Proposal No. 1060; Sec. 25.603; Part 1 - Agenda Item H-26.

7-29. By redesignating Sec. 25.605 as Sec. 25.605(a) and by adding a new Sec. 25.605(b) to read as follows:

Sec. 25.605 Fabrication methods.
* * * * *
(b) Each new aircraft fabrication method must be substantiated by a test program.

Explanation. This proposal would ensure that new aircraft fabrication methods are tested to determine their soundness.
Ref. Proposal Nos. 213, 1061; Sec. 25.605; Part 1 - Agenda Item H-27.

Sec. 25.613 [Amended]
7-30. By amending Sec. 25.613(e) in a manner substantively identical to that proposed for Sec. 23.613(c).

7-31. By deleting the dash at the end of Sec. 25.629(d)(1) and adding in its place the words "each of the following" followed by a colon; by deleting the semicolon and the word "and" at the end of Sec. 25.629(d)(1)(i) and adding a period in its place: and by revising Secs. 25.629(d)(1)(ii), (d)(4)(v), and (d)(4)(vi) to read as follows:

Sec. 25.629 Flutter, deformation, and failsafe criteria.
* * * * *
(d) * * *
(1) * * *
(ii) Any other combination of failures not shown to be extremely improbable.
* * * * *
(4) * * *
(v) Failure of each principal structural element selected for compliance with Sec. 25.571(c). Safety following a failure may be substantiated by showing that losses in rigidity or changes in frequency, mode shape, or damping are within the parameter variations shown to be satisfactory in the flutter and divergence investigations.
(vi) Any single failure or malfunction, or combinations thereof, in the flight control system considered under Secs. 25.671, 25.672, and 25.1309, and any single failure in any flutter damper system. Investigation of forced structural vibration other than flutter, resulting from failures, malfunctions, or adverse conditions in the automatic flight control system may be limited to airspeeds up to VC.

Explanation. The purpose of this proposal is to reflect the objectives of the system failure criteria adopted in Amendment 25-23. Service experience has indicated that the current standards relating to flutter stability are not sufficiently objective and comprehensive to cover modern complex transport airplanes. The revised wording proposed for paragraphs (d)(1)(ii), (d)(4)(v) and (d)(4)(vi) would require the designer to look at all combinations of system and structural failures which could affect flutter stability.
Ref. Proposal No. 1063; Sec. 25.629(d); Part 1 - Agenda Item H-32.

7-32. By revising Sec. 25.697(b) to read as follows:

Sec. 25.697 Lift and drug devices, controls.
* * * * *
(b) Each lift and drag device control must be designed and located to make inadvertent operation improbable. Lift and drag devices intended for ground operation only must have means to prevent the inadvertent operation of their controls in flight if that operation could be hazardous.
* * * * *

Explanation. For lift and drag devices intended to be used during ground operation only, the present requirement has been shown to be inadequate by service experience. FAA believes it necessary to require that such devices be inoperable in flight if their activation could result in a hazardous condition.
Ref. Proposal No. 144; Sec. 25.697(b); Part 1 - Agenda Item I-41.

7-33. By revising Sec 25.701(a) to read as follows:

Sec. 25.701 Flap interconnection.
(a) Unless the airplane has safe flight characteristics with the flaps retracted on one side and extended on the other, the motion of flaps on opposite sides of the plane of symmetry must be synchronized by a mechanical interconnection or equally reliable means.
* * * * *

Explanation. The proposal would revise Sec. 25.701(a) to provide for the use of means that are equally reliable to the means presently required by the section.
Ref. Proposal No. 227; Sec. 25.701(a); Part 1 - Agenda Item I-42.

7-34. By revising Sec. 25.723(a) to read as follows:

Sec. 25.723 Shock absorption tests.
(a) It must be shown by energy absorption tests or analysis based on tests conducted on a similar landing gear system that the limit load factors selected for design in accordance with Sec. 25.473 for takeoff and landing weights, respectively, will not be exceeded.
* * * * *

Explanation. The purpose of this proposal is to allow substantiation of the limit load factors for increase to the approved takeoff and landing weights to be accomplished by analysis.
Ref. Proposal No. 228, Sec. 25.723; Part 1 - Agenda Item J-43.

Sec. 25.737 [Amended]
7-35. By amending Sec. 25.737 in a manner substantively identical to that proposed for Sec. 23.737.

7-36. By adding a new Sec. 25.773(d) to read as follows:

Sec. 25.773 Pilot compartment view.
* * * * *
(d) Fixed markers or other guides must be installed at each pilot station to enable the pilots to position themselves in their seats for optimum outside visibility and instrument scan. If lighted markers or guides are used they must comply with the requirements specified in Sec. 25.1381.

Explanation. It has been observed during some training flights and en route inspections that the pilot does not have his seat in the correct position, thereby reducing his outside visibility and instrument scan. This proposal results from those observations.
Ref. Proposal No. 1071; Sec. 25.773; Part 1 - Agenda Item K-47.

Sec. 25.777 [Amended]
7-37. By deleting the measurement "6'0"" from Sec. 25.777(c) and replacing it with the measurement "6'3""; by deleting the word "belt" in Sec. 25.777(c) and replacing it with the words "belt and shoulder harness (if provided)": and by deleting the word "belts" in Sec. 25.777(f) and replacing it with the words ":belt and shoulder harness (if provided)".

Explanation. The flight stations of modern transport category airplanes have been designed for the 5th to 95th percentiles of pilot stature. Because the average human height continues to increase, the proposed change to Sec. 25.777(c) would increase the maximum flight crewmember height to be considered from 6'0" to 6'3" for the design of cockpit controls.
The proposal would also require the consideration of shoulder harnesses if provided.
Ref. Proposal No. 233; Sec. 25.777; Part 1 - Agenda Item K-48.

7-38. By amending Sec. 25.789 by inserting the words "or galley" after the words "crew compartment" and redesignating the paragraph as paragraph (a), and by revising the title and adding new paragraphs (b) and (c) to read as follows:

Sec. 25.789 Retention of items of mass in passenger and crew compartments and galleys.
* * * * *
(b) Each major galley components, including serving carts, drawers, and compartments must have a placard indicating its maximum load.
(c) Each interphone restraint system must be designed so that when subjected to the load factors specified in Sec. 25.561(b)(3), the interphone will remain in its stowed position.

Explanation. This proposed change would require placards on galley components so as to minimize their inadvertent overloading and failure. It would also require that the interphone restraint system be designed to withstand the load factors specified in Sec. 25.561(b)(3).
Ref. Proposal No. 240; Sec. 25.789; Part 1 - Agenda Item K-57.

7-39. By adding a new Sec. 25.802 to read as follows:

Sec. 25.802 Evacuation alarm systems.
Each evacuation alarm system required by the operating rules of this chapter must be installed so that -
(a) It can be activated on the flight deck and at each flight attendant's seat;
(b) It will operate, with or without utilizing the airplane's normal electrical power;
(c) It is not likely to be inadvertently activated by passengers or crewmembers; and
(d) In the event the system is activated, the alarm is perceivable by all passengers and crewmembers on the airplane, including those persons located in the galleys, lavatories, lounges or on any passenger deck level.

Explanation. The purpose of this proposal and the proposal for Sec. 121.292 is to establish standards for evacuation alarm systems and to require their installation in airplanes operated under Part 121. The FAA believes that during an emergency, an alarm system which can be perceived by all passengers and crewmembers located anywhere on the airplane is vital.
Ref. Proposal No. 139; FAR 5; Part 1 - Agenda Item L-65.

7-40. By revising Secs. 25.803(c) and (d) to read as follows:

Sec. 25.803 Emergency evacuation.
* * * * *
(c) Except as provided in paragraph (d) of this section, for airplanes having a seating capacity of more than 44 passengers, it must be shown by actual demonstration, that the maximum seating capacity, including the number of crewmembers required by the operating rules for which certification is requested, can be evacuated from the airplane to the ground within 90 seconds. The demonstration must be conducted under the following conditions:
(1) It must be conducted either during the dark of the night or during daylight with dark of the night simulated. If the demonstration is conducted indoors during daylight hours, it must be conducted with each window covered and each door closed to minimize the daylight effect. Illumination on the floor or ground may be used, but it must be kept low and shielded against shining into the airplane's windows or doors.
(2) The airplane must be in a normal attitude with landing gear extended.
(3) Stands or ramps may be used for descent from the wing to the ground, and safety equipment such as mats or inverted life rafts may be placed on the floor or ground to protect participants. No other equipment that is not part of the airplane's emergency evacuation equipment may be used to aid the participants in reaching the ground.
(4) The airplane's normal electrical power sources must be de-energized.
(5) All emergency equipment must be installed in accordance with Secs. 25.1411 and 25.1415.
(6) Each external door and exist, and each internal door or curtain, must be in the takeoff configuration.
(7) A representative passenger load of persons in normal health must be used as follows:
(i) At least 30 percent must be females.
(ii) At least 5 percent must be over 60 years of age with a proportionate number of females.
(iii) At least 5 percent, but not more than 10 percent, must be children under 12 years of age, prorated through that age group.
(iv) Three life-size dolls, not included as part of the total passenger load, must be carried by passengers to simulate live infants 2 years old or younger.
(v) Crewmembers, mechanics, and training personnel, who maintain or operate the airplane in the normal course of their duties, may not be used as passengers.
(8) No passenger may be assigned a specific seat except as the Administrator may require. Except as required by paragraph (c)(11) of this section, no employee of the applicant may be seated next to an emergency exit.
(9) Seat belts and shoulder harnesses (as required) must be fastened.
(10) Before the start of the demonstration, approximately one-half of the total average amount of carry-on baggage, blankets, pillows, and other similar articles must be distributed at several locations in the aisles and emergency exists access ways to create minor obstructions.
(11) Each crewmember must be seated in his normally assigned seat for takeoff and must remain in that seat until receiving the signal for commencement of the demonstration.
(12) No indication may be given to any crewmember or passenger of the particular exits to be used in the demonstration.
(13) The applicant may not practice, rehearse, or describe the demonstration for the participants nor may any participant have taken part in this type of demonstration within the preceding 6 months.
(14) The pretakeoff passenger briefing required by Sec. 121.571 of this chapter may be given. The passengers may also be warned to follow directions of crewmembers, but not be instructed on the procedures to be followed in the demonstration.
(15) If safety equipment as allowed by paragraph (c)(3) of this section is provided, either all passenger and cockpit windows must be blacked out or all of the emergency exists must have safety equipment in order to prevent disclosure of the available emergency exists.
(16) Not more than 50 percent of the emergency exits in the sides of the fuselage of an airplane that meet all of the requirements applicable to the required emergency exits for that airplane may be used for the demonstration. Exits that are not to be used in the demonstration must have the exit handle deactivated or must be indicated by red lights, red tape or other acceptable means, placed outside the exits to indicate fire or other reason why they are unusable. The exits to be used must be representative of all of the emergency exits on the airplane and must be designated by the applicant, subject to approval by the Administrator. At least one floor level exit must be used. Multi-deck airplanes must include inoperative exits on each deck that may be occupied during takeoff and landing.
(17) All evacuees, except those using an over-the-wing exit (must leave the airplane by a means provided as part of the airplane's equipment.
(18) The applicant's approved procedures and all of the emergency equipment that is normally available, including slides, ropes, lights, and megaphones, must be fully utilized during the demonstration.
(19) The evacuation time period is completed when the last occupant has evacuated the airplane and is on the ground. Evacuees using stands or ramps allowed by paragraph (c)(3) of this section are considered to be on the ground when they are on the stand or ramp, provided. That the passage width of the stand or ramp is no greater than the acceptance rate of the means available on the airplane for descent from the wing during an actual crash situation.
(d) Analysis or a combination of analysis and tests may be used to show that the airplane is capable of being evacuated within 90 seconds under the conditions specified in Sec. 25.803(c) of this section if the Administrator finds that the analysis or the combination of analysis and tests will provide data with respect to the emergency evacuation capability of the airplane equivalent to that which would be obtained by actual demonstration.
* * * * *

Explanation. The purpose of revising Sec. 25.803 is to allow means other than actual demonstration to be used to comply with the emergency evacuation performance requirements and to replace the present demonstration conditions with conditions which satisfy both Part 25 and Part 121, thus providing for one demonstration that serves both airworthiness and operational requirements. In addition, a condition regarding multideck airplanes, having more than one deck occupied during takeoff or landing, has been added.
Ref. Proposal Nos. 243, 244, 1079; Sec. 25.803, Sec. 25.803(c); Part 1 - Agenda Items L-62, L-63, L-64.

7-41. By revising Sec. 25.807(a)(7)(vi); by deleting the term "(6)" in Sec. 25.807(e)(1) and replacing it with the term "(7)", and by adding a new Sec. 25.807(c)(7) to read as follows:

Sec. 25.807 Passenger emergency exits.
(a) * * *
(7) * * *
(vi) There must be at least one flight attendant seat, which meets the requirements of Secs. 25.785(h) and (i), adjacent to each such exit.
* * * * *
(c) * * *
(7) For airplanes with more than one passenger deck level that may be occupied during takeoff or landing, the following apply:
(i) Each emergency exit in the side of the fuselage must be either a Type A or Type I exit.
(ii) A passenger seating configuration of 100 seats is allowed for a deck for each pair of Type A exits on that deck and a passenger seating configuration of 45 seats is allowed for a deck for each pair of Type I exits on that deck.
(iii) An emergency exit distribution must be provided that affords the most effective means of passenger evacuation, taking into account the passenger distribution on each deck and the location of the stairway to the main deck.
(iv) For airplanes with a passenger deck located below the main deck, means must be provided near the operating handle of each lower deck emergency exit to enable an occupant to determine the condition of the outside environment in the area outside that exit for which exterior emergency lighting is required by Sec. 25.812.
* * * * *

Explanation. This proposal is related to the proposal for Secs. 25.561 and 25.813. The purpose of this proposal is to establish the passenger emergency exit requirements for multi-deck airplanes with two or more decks occupiable by passengers during takeoff or landing. This proposal is based on the existing special conditions developed for the current wide body jet airplanes.
In addition, the proposal would amend Sec. 25.807(a)(7)(vi) to require that there be a flight attendant seat adjacent to each Type A emergency exit. Passenger safety often depends upon the flight attendant's ability to function quickly and decisively in an emergency. The FAA believes that the proposal would enhance the flight attendant's ability to aid in the event of emergency evacuation.
Notice No. 75-10 (40 FR 10802; March 7, 1975) contains a proposal for Sec. 25.785 which if adopted would necessitate revision of the paragraph designations reference in the proposal for Sec. 25.807(a)(7)(vi).
Ref. Proposal Nos. 246, 1083; Sec. 25.807(a), Sec. 25.807(e); Part 1 - Agenda Items K-51, L-67.

7-42. By adding a new Secs. 25.809(f)(1)(iv) and (f)(1)(v) to read as follows:

Sec. 25.809 Emergency exit arrangement.
* * * * *
(f) * * *
(1) * * *
(iv) It must have the capability after full deployment, to remain useable without outside assistance, to evacuate passengers safely to the ground in 25 knot winds directed from the most critical angle.
(v) The installed system must be shown to be 98 percent reliable in accordance with the following tests or other approved equivalent method. A series of not less than 35 consecutive deployment and inflation tests must be conducted with no failures, or 85 consecutive deployment and inflation tests must be conducted with no more than one failure. For each system installation (mockup or airplane installed) the tests must be equally divided among 5 representative samples of the device. (All possible assembly variations must be accounted for.) The sample devices must be deployed and inflated by the system's primary means after being subjected to the inertia forces specified in section 23.561(b). If any part of the system fails or does not function properly during the required tests, the cause of failure or malfunction must be corrected by positive means and retested.
* * * * *

Explanation. The purpose of this proposal is to establish wind condition criteria to be accounted for in the evaluation of evacuation slide installations and to provide for improved escape slide performance in view of recent adverse service experience.
Ref. Proposal No. 1084; Sec. 25.809(f)(1)(iv); Part 1 - Agenda Item L-68.

7-43. By revising Sec. 25.811(e) to read as follows:

Sec. 25.811 Emergency exit marking.
* * * * *
(e) The location of the operating handle and instructions for opening the exit from the inside must be shown in the following manner:
(1) Each passenger emergency exit must have, on or near the exit, a marking that is readable form a distance of 30 inches.
(2) Each Type I and Type A passenger emergency exit operating handle must -
(i) Be self-illuminated with an initial brightness of at least 160 microlamberts; or
(ii) Be conspicuously located and well illuminated by the emergency lighting even in condition of occupant crowding at the exit.
(3) Each Type III passenger emergency exit operating handle must be self-illuminated with an initial brightness of at least 160 microlamberts. If the operating handle is covered, self-illuminated cover removal instructions having an initial brightness of at least 160 microlamberts must also be provided.
(4) Each Type A, Type I and Type II passenger emergency exit with a locking mechanism released by rotary motion of the handle must be marked -
(i) With a red arrow, with a shaft at least three-fourths inch wide and a head twice the width of the shaft, extending along at least 70 of arc at a radius approximately equal to three-fourths of the handle length;
(ii) So that the centerline of the exit handle is within 0.5 inches of the projected point of the arrow when the handle has reached full travel and has released the locking mechanism; and
(iii) With the word "open" in red letters 1 inch high, placed horizontally near the head of the arrow.
* * * * *

Explanation. The first purpose of the proposal is to clarify the current rule so as to insure that the markings give a clear indication of how far the exit handle must be moved to release the locking mechanism.
The second purpose is to require that Type I and Type A emergency exit handles be self-illuminated, or conspicuously located and illuminated to the extent that they would still be easily located under conditions of occupant crowding at the exit. Experience indicates that during an emergency a passenger may become confused and, therefore, the more conspicuous the emergency exit operating handle is, the more likely that the passenger will be able to safely evacuate.
Ref. Proposal Nos. 248, 719; Sec. 25.811, Sec. 25.811(e); Part 1 - Agenda Item L-69.

7-44. By deleting the parenthetical expression in Sec. 25.812(e)(1); by revising Secs. 25.812(e)(2), (e)(3), (f)(1)(iii), (f)(2), (g)(1), and (g)(2)(ii); and by adding a new sec. 25.812(1) to read as follows:

Sec. 25.812 Emergency lighting.
* * * * *
(e) * * *
(2) There must be a flight crew warning light which illuminates when power is on in the airplane and the emergency lighting control device is not armed.
(3) The cockpit control device must have an "on", "off", and "armed" position so that when armed in the cockpit or turned on at either the cockpit or flight attendant station the lights will either light or remain lighted upon interruption (except an interruption caused by a transverse vertical separation of the fuselage during crash landing) of the airplane's normal electric power. There must be a means to safeguard against inadvertent operation of the control device form the "armed" or "on" positions.
(f) * * *
(1) * * *
(iii) Not less than 0.03 foot-candle (measured normal to the direction of the incident light) on the ground surface where an evacuee using the established escape route would normally make first contact with the ground, with the airplane in each of the following configurations:
(a) Landing gear extended.
(b) One or more of the landing gear collapsed.
(c) Landing gear retracted.
(2) At each non-overwing emergency exit not required by Sec. 25.809(f) to have descent assist means, the illumination must not be less than 0.03 foot-candle (measured normal to the direction of the incident light) on the ground surface where an evacuee would normally make first contact with the ground, with the airplane in each of the following configurations:
(i) Landing gear extended.
(ii) One or more of the landing gear collapsed.
(iii) Landing gear retracted.
(g) * * *
(1) If the assist means is illuminated by exterior emergency lighting, it must provide illumination of not less than 0.03 foot-candle (measured normal to the direction of the incident light) at the ground end of the erected assist means where an evacuee using the established escape route would normally make first contact with the ground, with the airplane in each of the following configurations:
(i) Landing gear extended.
(ii) One or more of the landing gear collapsed.
(iii) Landing gear retracted.
(2) * * *
(ii) Must provide illumination of not less than 0.03 foot-candle (measured normal to the direction of incident light) at the ground end of the erected assist means where an evacuee would normally make first contact with the ground, with the airplane in each of the following configurations:
(a) Landing gear extended.
(b) One or more of the landing gear collapsed.
(c) Landing gear retracted.
* * * * *
(1) Portable, self-powered high intensity lights must be installed so that at least one readily is accessible from each flight attendant seat.

Explanation. One purpose of this proposal is to establish a requirement for all Part 25 airplanes that the emergency lighting system be operable from a point in the passenger compartment that is readily accessible to a flight attendant seat. This amendment is necessary since numerous large transports are being operated under Part 91 carrying non-fee paying passengers and "flight attendants".
Section 25.812(e)(2) would be revised by replacing the words "neither armed nor turned on with not armed", thereby eliminating the possibility of discharged batteries in some designs.
Section 25.812(e)(3) would be revised to expand the existing rule with respect to the function of the control device for the emergency lighting system.
Another purpose of this proposal is to extend the ground surface illumination requirements in Secs. 25.812(f) and (g) to provide coverage with an airplane in abnormal attitudes. Abnormal attitudes can reasonably be expected during situations which necessitate emergency evacuation and should therefore be provided for in design requirements.
The last purpose of this proposal is to add a new paragraph (1) to require a portable, self-powered high intensity light at each flight attendant seat for use during emergencies. Recent accident investigations have indicated that the absence of adequate emergency lighting seriously hampered the passengers' ability to orient themselves and prevented them from searching for, or assisting, other injured passengers. Additionally, the absence of sufficient light prevented the flight attendants from effectively coordinating evacuation and aid efforts.
Ref. Proposal Nos. 249, 720, 721, 722: Sec. 25.812, Sec. 25.812(e), Sec. 25.812(e)(2); Part 1 - Agenda Items L-70, L-71, L-72.

7-45. By revising Sec. 25.813(c)(1) and adding a new Secs. 25.813(g), (h), and() to read as follows:

Sec. 25.813 Emergency exit access.
* * * * *
(c) * * *
(1) For airplanes that have a passenger seating configuration, excluding pilot's seats, of 20 or more, the projected opening of the exit provided must not be obstructed and there must be no interference in opening the exit by seats, berths, or other protrusions (including seatbacks in any position, for a distance from that exit not less than the width of the narrowest passenger seat installed on the airplane.
* * * * *
(g) Each passageway of a ventral or tall cone exit that may be used during an emergency evacuation, and any passageway leading through a cargo or baggage compartment to an emergency exit, must be completely enclosed on the sides, floor, and ceiling, with materials which meet the applicable requirements of Secs. 25.8653(a) and (b). No flammable fluid source or source of ignition, except the normal and emergency lighting systems, may be in the passageway.
(h) For airplanes with more than one passenger deck level that may be occupied during takeoff or landing, each passageway between decks must be a stairway, or its equivalent. In addition the following apply:
(1) The stairway must -
(i) Have essentially straight route segments with a landing at each significant change in segment direction;
(ii) Have rectangular treads;
(iii) Have entrance, exit, and gradient characteristics that would allow, with the airplane in level attitude and in each attitude resulting from the collapse of any one or more legs of the landing gear, the passengers of each deck without assistance of a crewmember, to commingle with passengers of any other deck during an emergency evacuation and leave the airplane through the exits of that deck. This must be shown by demonstration, test, analysis, or any combination thereof except that a demonstration in level attitude is required for at least one stairway during which a representative passenger capacity of one deck commingles with a representative passenger capacity of the other decks and this combination of passengers leaves the airplane through the exits of that deck;
(iv) Accommodate the carriage of an incapacitated person from one deck to another. The crewmember procedures for such carriage must be established;
(v) Be located to provide evacuees an adequate ascent and descent rate under probable emergency conditions, including the condition in which a person falls or is incapacitated while on it; and
(vi) Be designed and located to minimize damage to it during an emergency landing or ditching.
(2) General illumination must be provided so that, when measured along the center lines of each tread and landing of the stairway, the illumination is not less than 0.05 foot-candle.
(3) Means must be provided at the stairway to retard the propagation of fire and the transmission of smoke between the passenger decks. The means must be located to be readily available for placement.
(4) Means must be provided to assist the occupants in locating the stairway in conditions of dense smoke.
(5) Stairway location must be indicated by a passenger stairway sign above each stairway entrance visible to passengers approaching along the main passenger aisle. There must be a sign on each bulkhead or divider to indicate stairways beyond the bulkhead or divider if the bulkhead or divider prevents fore and aft vision of the passenger stairway along the passenger cabin except that, if this is not possible, the sign may be placed in another appropriate location. These signs must meet the applicable requirements specified in Sec. 25.812(b)(1)(ii).
(6) The adequacy of the number and distribution of stairways must be established to provide evacuees from one deck a sufficient egress rate to the adjacent deck under probable emergency conditions, including the condition in which a person falls or is incapacitated while on the stairs. At least one stairway must be provided for each pair of Type I exits, and at least two stairways must be provided for each pair of Type A exits (based on the deck to be connected by the stairway with the smallest seating capacity).
(i) For airplanes with more than one passenger deck level that may be occupied during takeoff or landing, each deck must have a sign legible to each person on that deck under all probable conditions of cabin illumination, which indicates that additional exits are located on the other decks.

Explanation. Proposed Sec. 25.813(c)(1) would clarify the rule with respect to whether the projected opening is the opening in the aircraft fuselage or in the space through which the exit door passes in removing the door from the exit. As an example, Type IV exists usually require some clearance in addition to the projected opening in the fuselage to clear the seatback located just forward of the exit. This proposal would eliminate the need for future interpretation of this rule by adding the words "and there must be no interference in opening the exit."
Proposed Sec. 25.813(g) would establish the material and systems requirements for any passageway located in the ventral or tail cone area that may be used during an emergency evacuation and any passageway leading through a cargo or baggage compartment to an emergency exit.
Proposed Secs. 25.813(h) and (i) would establish needed passageway design requirements for airplane with more than one passenger deck level that may be occupied during takeoff or landing. This addition is related to the proposal for Secs. 25.561(a) and 25.807(e).
It should be noted that this proposal would prohibit the installation of spiral stairways on future multideck passenger airplanes even though these stairways have been approved for use in the past. The FAA believes that a stairway, with essentially straight route segments and with a landing at each significant change in segment direction, is easier to traverse and therefore provides better evacuation characteristics than does a spiral stairway.
Ref. Proposal Nos. 725, 726, 1082; Sec. 25.807(c), Sec. 25.813(c)(1), Sec. 25.813(g) and (h); Part 1 - Agenda Items L-66, L-67, L-73.

7-46. By adding a new Sec. 25.831(g) to read as follows:

Sec. 25.831 Ventilation.
* * * * *
(g) Each galley and passenger service area must meet the requirements specified in paragraphs (a) and (b) of this section.

Explanation. This proposal would amend the existing rule to extend the requirements of Secs. 25.831(a) and (b) to galley and passenger service areas, including those on a lower deck, if applicable.
Ref. Proposal No. 240; Sec. 25.789; Part 1 - Agenda Item K-57.

Sec. 25.863 [Amended]
7-47. By revising Sec. 25.863(a) to be substantively identical to proposed Sec. 23.863(a) and by adding a new Sec. 25.863(d) that would be substantively identical to the proposed new Sec. 23.863(d).

Sec. 25.1307 [Amended]
7-48. By deleting the words "and safety belts," from Sec. 25.1307(a).
Explanation. The purpose of this proposal is to eliminate duplication. Section 25.785 requires a safety belt.
Ref. Proposal No. 949; Sec. 29.1307(b); Part 2 - Agenda Item B-11.

7-49. By revising Sec. 25.1411(a) and (d), deleting the word "and" form the end of Sec. 25.1411(b)(1), adding a semicolon and the word "and" at the end of Sec. 25.1411(b)(2), and adding a new sec. 25.1411(b)(3) and (h) to read as follows:

Sec. 25.1411 General.
(a) Accessibility.
(1) Required safety equipment to be used by the crew in an emergency, such as automatic liferaft releases, must be readily accessible.
(2) Each public address system microphone intended for flight attendant use and each required item of emergency equipment such as fire extinguishers, portable oxygen bottles, and first-aid kits, must be positioned adjacent to each flight attendant seat and be readily accessible to the seated flight attendant. No equipment may be located so as to adversely-affect the safety of the flight attendant under any condition.
(b) * * *
(3) Be placarded to indicate the contents of each stowage compartment and container.
* * * * *
(d) Liferafts.
(1) The stowage provisions for the liferafts described in Sec. 25.1415 must accommodate enough rafts for the maximum number of occupants for which certification for ditching is requested.
(2) Liferafts must be stowed near exits through which the rafts can be launched during an unplanned ditching.
(3) Rafts automatically or remotely released outside the airplane must be attached to the airplane by means of the static line prescribed in Sec. 25.1415.
(4) The stowage provisions for each portable liferaft must allow rapid detachment and removal of the raft for use at other than the intended exists.
* * * * *
(h) Equipment marking. Required safety equipment must be clearly identified, and if its mode of operation would not be obvious to airplane passengers it must be clearly marked with operating instructions located on the equipment.

Explanation. Section 25.1411(a) would be revised to require that standard emergency equipment be readily accessible to the seated flight attendant. The change is necessary to enable the flight attendant to render rapid assistance in emergency situations.
Section 25.1411(b)(3) would be added to require that permanent placards on all compartments and containers to provide information of their contents.
Section 25.1411(d) would be revised to require portable liferaft stowage provisions be designed to allow use of the raft at other than the intended exit. This change is necessitated by development of slide/raft systems to handle large numbers of occupants. It is necessary that the existing level of safety be maintained relative to accessibility, portability and deployment of such devices. Consequently, as raft size and packaged weight increases, provisions must be made to assure portability when applicable. The revision to Sec. 25.1411(d) is related to the proposal for Sec. 25.1415(b).
Section 25.1411(h) would be added to require that emergency equipment be clearly marked to indicate its method of operation. The FAA believes that if emergency equipment is to serve its function it must be clearly marked so that its mode of operation is obvious to the intended user.
Ref. Proposal Nos. 314, 803; Secs. 25.1411, 25.1411(d); Part 1 - Agenda Items O-84, O-85.

Sec. 25.1413 [Amended]
7-50. By amending Sec. 25.1413(b) in a manner substantively identical to that proposed for Sec. 23.1413(a).

7-51. By deleting from Sec. 25.1415(b)(1) the word "and" following the semicolon, inserting at the end of Sec. 251415(b)(2) a semicolon, and adding Sec. 25.1415(b)(3), (4), and (5) to read as follows:

Sec. 25.1415 Ditching equipment.
* * * * *
(b) * * *
(3) Each portable raft must be readily movable within the airplane cabin by not more than two persons to other exit locations which are likely to be usable under the expected water conditions and airplane ditching characteristics established in accordance with Sec. 25.801:
(4) If any of the rafts installed in the airplane are not portable the rafts installed must provide flotation at rated capacity for all occupants of the airplane with one-half of the non-portable rafts not used; and
(5) There must be means to assist the occupants in boarding each raft from the airplane without entering the water, and it must be demonstrated that this means is functional for the rated capacity of the raft, under expected water conditions and airplane ditching characteristics established in accordance with Sec. 25.801.
* * * * *

Explanation. This proposal is related to the proposal for -25.1411(d). It would require that rafts either be portable, a condition that now exists throughout the industry, or non-portable in which case additional rafts must be provided. Portable rafts would be required to be readily movable to all exits which are likely to remain usable after the airplane has been ditched in the water. In addition, this proposal would require that a means be provided to assist the airplane occupants into the rafts.
Ref. Proposal No. 804; Sec. 25.1415(b); Agenda Item O-85.

Sec. 25.1416 [New]
7-52. By adding a new Sec. 25.1416 that would be substantively identical to the proposed new Sec. 23.1416.

7-53. By adding a new Sec. 25.1423 to read as follows:

Sec. 25.1423 Intercommunication equipment.
For airplanes with adjacent passenger decks, an intercom and a two-way alerting means between passenger decks and between each passenger deck and the flight deck must be provided that meet the following requirements:
(a) They must remain operable in the event of the loss of the main power supply.
(b) they must be capable of providing crewmembers on all decks an immediate indication of an emergency situation on any deck.

Explanation. The proposal for Sec. 25.1423 would establish the needed intercommunication equipment requirements for multi-deck airplanes. This proposal is related to the proposal for Sec. 25.813.
Ref. Proposal No. 726; Secs. 25.813(g) and (h); Part 1 - Agenda Item L-67.

Sec. 25.1561 [Amended]
7-54. By inserting the words "the easy" between the words "facilitate" and "removal" in Sec. 25.1561(c).
Explanation. See the proposal for Sec. 25.1411.
Ref. Proposal No. 329; Sec. 25.1561(c); Part 10 - Agenda Item O-89.

7-55. By adding a new Appendix G to Part 25 to read as follows:

APPENDIX G
CONTINUOUS GUST DESIGN CRITERIA

The continuous gust design criteria in this appendix must be used in establishing the dynamic response of the airplane to vertical and lateral continuous turbulence unless a more rational criteria is used. The following gust load requirements apply to mission analysis and design envelope analysis:
(a) The limit gust loads utilizing the continuous turbulence concept must be determined in according with the provisions of either paragraph (b) or paragraphs (c) and (d) of this appendix. For components stressed by both vertical and lateral components of turbulence, the resultant combined stress must be considered. The combined stress may be determined on the assumption that vertical and lateral components are independent.
(b) Design envelope analysis. The limit loads must be determined in accordance with the following:
(1) All critical altitudes, weights, and weight distributions, as specified in Sec. 25.321(b), and all critical speeds within the ranges indicated in paragraph (b)(3) of this appendix must be considered.
(2) Values of (ratio of root-mean-square incremental load to root-mean-square gust velocity) must be determined by dynamic analysis. The power-spectral density of the atmospheric turbulence must be as given by the equation -



where:
= power-spectral density (ft/sec.)2/rad./ft.
= root-mean-square gust velocity, ft./sec.
= reduced frequency, radians per foot.
L=2,500 ft.

(3) The limit loads must be obtained by multiplying the values determined by the dynamic analysis by the following values of :
(i) At speed VC: = 85 ft./sec., true gust velocity on the interval 0 to 30,000 ft. altitude and is linearly decreased to 30 ft./sec., true at 80,000 ft. altitude.
(ii) At speed VB: is equal to 1.32 times the values obtained under paragraph (b)(3)(i) of this appendix.
(iii) At speed VD: is equal to the values obtained under paragraph (b)(3)(i) of this appendix.
(iv) At speeds between VB and VC and between VC and VD: is equal to a value obtained by linear interpolation.
(4) When a stability augmentation system is included in the analysis, the effect of system nonlinearities on loads at the limit load level must be realistically or conservatively accounted for.
(c) Mission analysis. Limit loads must be determined in accordance with the following:
(1) The expected utilization of the airplane must be represented by one or more flight profiles in which the load distribution and the variation with time of speed, altitude, gross weight, and center of gravity position are defined. These profiles must be divided into mission segments, or blocks, for analysis, and average or effective values of the pertinent parameters defined for each segment.
(2) For each of the mission segments defined under paragraph (c)(1) of this appendix, values of and Ne must be determined by analysis. is defined as the ratio of root-mean-square incremental load to root-mean-square gust velocity and Ne as the radius of gyration of the load power-spectral density function about zero frequency. The power-spectral density of the atmospheric turbulence must be given by the equation set forth in paragraph (b)(2) of this appendix.
(3) For each of the load and stress quantities selected, the frequency of exceedance must be determined as a function of load level by means of the equation -



where:
t = selected time interval.
y = net value of the load or stress.
= value of the load or stress in one-g level flight
N(y) = average number of exceedances of the indicated value of the load or stress in unit time.
= symbol denoting summation over all mission segments.
No, = parameters determined by dynamic analysis as defined in paragraph (c)(2) of this appendix.
P1, P2, b1, b2 = parameters defining the probability distributions of root-mean-square gust velocity, to be read from Figures 1 and 2 of this appendix.

The limit gust loads must be read from the frequency of exceedance curves at a frequency of exceedance of 2X10-5 exceedances per hour. Both positive and negative load directions must be considered in the determining of the limit loads.
(4) If a stability augmentation system is utilized to reduce the gust loads, consideration must be given to the fraction of flight time that the system may be inoperative. The flight profiles of paragraph (c)(1) of this appendix must include flight with the system inoperative for this fraction of the flight time. When a stability augmentation system is included in the analysis, the effect of system nonlinearities on loads at the limit load level must be conservatively accounted for.
(d) Supplementary design envelope analysis. In addition to the limit and fail-safe loads defined by paragraph (c) of this appendix, limit and fail-safe loads must also be determined in accordance with paragraph (b) of this appendix, except that -

Figure 1 - P1 and P2 Values



Figure 2 - b1 and b2 Values

(1) In paragraph (b)(3)(i) of this appendix, the value of = 85 ft./sec., true is replaced by = 60 ft./sec., true on the interval 0 to 30,000 ft. altitude, and is linearly decreased to 25 ft./sec., true and 30,000 ft. altitude; and
(2) In paragraph (b) of this appendix, the reference to paragraphs (b)(3)(i) through (b)(3)(iii) of this appendix is to be understood as referring to the paragraph as modified by paragraph (d)(1).
(e) Response to turbulence at pilot's station. The vertical and lateral acceleration environment at the pilot's station must be established for response to continuous turbulence at intensity levels encountered in normal operations. Adequacy of levels of turbulence encountered in normal operations may be shown by analysis based on a comparison with airplanes which have acceptable service experience.

Explanation. The proposal provides continuous gust design criteria for establishing the dynamic response of the airplane to vertical and lateral continuous turbulence.
Ref. Proposal No. 837; Part 25 - Appendix G; Part 1 - Agenda Item A-2.

PART 27 - AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT

Sec. 27.603 [Amended]
7-56. By adding a new Sec. 27.603(c) that would be substantively identical to the proposed new Sec. 25.603(c).

Sec. 27.605 [Amended]
7-57. By redesignating Sec. 27.605 as Sec. 27.605(a) and adding a new Sec. 27.605(b) that would be substantively identical to the proposed new Sec. 25.605(b).

Sec. 27.613 [Amended]
7-58. By amending Sec. 27.613(d) in a manner substantively identical to that proposed for Sec. 23.613(c).

7-59. By adding new Sec. 27.671(c), (d), (e), and (f) to read as follows:

Sec. 27.671 General.
* * * * *
(c) It must be shown by analysis, test or both, that the rotorcraft can be operated safely in flight and landed without necessitating exceptional piloting skill or strength after each of the following failures in the flight control system;
(1) Any single failure in the power portion of the control system, including a crack in a hydraulic housing or a jammed control valve. The power portion includes the power source (such as a hydraulic pump), valves, lines, actuators, and other power operated devices but excludes purely structural elements such as actuator lugs and piston rods.
(2) The jamming of power cylinders unless their failure is shown to be extremely improbable.
(d) It must be shown by analysis, test or both, that the probability of the rotorcraft becoming incapable of continued safe flight and landing (without requiring exceptional piloting skill or strength) following a failure of any single element in a movable joint or in any fatigue critical area has been minimized.
(e) Probable malfunctions must have only minor effects of control system operation and must be capable of being readily counteracted by the pilot.
(f) The rotorcraft must be capable of continued safe flight and landing if all engines fail.

Explanation. This proposal is related to the proposal for Sec. 27.695. Existing regulations require the capability of safe flight and landing of rotorcraft after any single failure in the power portion of the control system except that jamming of power cylinders need not be considered if that is shown to be extremely improbable. The existing regulations require extensive redundancy in the power portion but not in the mechanical portion of the control system. The FAA believes that these requirements should be extended to cover the entire control system insofar as practicable. In addition, the proposed paragraph (d) would require an evaluation to show that the probability of the rotorcraft becoming incapable of continued flight and landing following failure of any single element in a movable joint or in any fatigue critical area has been minimized.
Ref. Proposal Nos. 846, 902; Sec. 27.671, Sec. 29.671; Part 2 - Agenda Item B-6.

7-60 By revising Sec. 27.674(d)(1) to read as follows:

Sec. 27.675 Stops.
* * * * *
(d) * * *
(1) Stops that are appropriate to the blade design must be provided to limit travel of the blade about its hinge points; and
* * * * *

Explanation. The present wording of Sec. 27.675(d)(1) implies that stops must be located at (and act on) the blade. The proposed wording would make it clear that other locations may be used.
Ref. Proposal No. 359, 393; Sec. 27.675(d), Sec. 29.675; Part 2 - Agenda Item B-7.

Sec. 27.695 [Deleted]
7-61. By deleting Sec. 27.695.
Explanation. This proposal is related to the proposal for Sec. 27.671. The purpose of these proposals is to relocate the requirements of Sec. 27.695 in sec. 27.671.
Ref. Proposal No. 847; Sec. 27.695; Part 2 - Agenda Item B-6.

Sec. 27.737 [Amended]
7-62. By amending Sec. 27.737 in a manner substantively identical to that proposed for Sec. 23.737.

Sec. 27.853 [Amended]
7-63. By amending Sec. 27.853 in a manner substantively identical to that proposed for Sec. 29.853.

Sec. 27.863 [New]
7-64. By adding a new Sec. 27.863 that would be substantively identical to the proposed new Sec. 23.863.

Sec. 27.1413 [Amended]
7-65. By amending Sec. 27.1413(a) in a manner substantively identical to that proposed for Sec. 23.1413(a).

7-66. By adding a new Sec 27.1463 to read as follows:

Sec. 27.1463 Tail rotor safety devices.
There must a means to prevent persons from inadvertently contacting the tail rotor of the rotorcraft.

Explanation. There continues to be a significant number of fatalities due to persons inadvertently walking into the tail rotor. The purpose of this proposal is to require a means to prevent this type of accident.
Ref. Proposal Nos. 876, 961; Sec. 27.1463, Sec. 29.1463; Part 2 - Agenda Item B-12.

PART 29 - AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT

Sec. 29.603 [Amended]
7-67. By adding a new Sec. 29.l603(c) that would be substantively identical to the proposed new Sec. 25.603(c).

Sec. 29.605 [Amended]
7-68 By redesignating Sec. 29.605 as Sec. 29.605(a) and adding a new Sec. 29.605(b) that would be substantively identical to the proposed new Sec. 25.605(b).

Sec. 29.613 [Amended]
7-69. By amending Sec. 9.613(d) in a manner substantively identical to that proposed for Sec. 23.613(c).

Sec. 29.671 [Amended]
7-70. By amending Sec. 29.671 in a manner substantively identical to that proposed for Sec. 27.671.

Sec. 29.675 [Amended]
7-71. By amending Sec. 29.675(d)(1) in a manner substantively identical to that proposed for Sec. 27.675(d)(1).

Sec. 29.695 [Deleted]
7-72. By deleting Sec. 29.695.
Explanation. This proposal is related to the proposal for Sec. 29.671. The purpose of these proposals is to relocate the requirements of Sec. 29.695 in Sec. 29.671.
Ref. Proposal No. 903; Sec. 29.695; Part 2 - Agenda Item B-6.

Sec. 29.737 [Amended]
7-73. By amending Sec. 29.737(a) in a manner substantively identical to that proposed for Sec. 23.737.

7-74. By deleting Sec. 29.853(b); by and marking "[Reserved]" it and revising Sec. 29.853(a) to read as follows:

Sec. 29.853 Compartment interiors.
* * * * *
(a) The materials must meet the requirements of Secs. 25.853(a) and 25.853(b) of this chapter.
* * * * *

Explanation. This proposal would significantly upgrade the flammability requirements for compartment interior materials for rotorcraft. Recent investigations of fires in rotorcraft have indicated that this upgrading is necessary.
Ref. Proposal No. 910; Sec. 29.853(a); Part 2 - Agenda Item B-9.

Sec. 29.863 [Amended]
7-75. By amending Sec. 29.863 amending to be substantively identical to the proposed new Sec. 23.863.

Sec. 29.1413 [amended]
7-76. By redesignating Sec. 29.1413 as Sec. 29.1413(a), adding a new sec. 29.1413(b) that would be substantively identical to the proposed Sec. 23.1413(a), and the section heading to read - "Sec. 29.1413 Safety belt and safety belt warning signs."

Sec. 29.1463 [New]
7-71. By adding a new Sec. 29.1463 that would be substantively identical to the proposed new Sec. 27.1463.

PART 121 - CERTIFICATION AND OPERATIONS: DOMESTIC, FLAG, AND SUPPLEMENTAL AIR CARRIERS AND COMMERCIAL OPERATORS OF LARGE AIRCRAFT

7-78. By Sec. 121.1291(a) inserting at the beginning of a phrase that reads - "Except for airplanes that were shown to be in compliance with Sec. 25.803(c) in effect on (the effective data of this amendment) during type certification," and adding a new Sec. 121.291(c) to read as follows:

Sec. 121.291 Demonstration of emergency evacuation procedures.
* * * * *
(c) For airplanes that where shown to be in compliance with Sec. 25.803(c) of this chapter in effect on (the effective date of this amendment) during type certification, the operator must show that its emergency evacuation procedures and the training provided its crewmembers with respect to those procedures will provide emergency evacuation results equivalent to those obtained under Sec. 25.803(c) of this chapter during airplane type certification.
* * * * *

Explanation. This proposal is related to the proposal for Sec. 25.803 and Appendix D to Part 121. See the explanation for these two proposals.
Ref. Proposal No. 524; Sec. 121.29, FAR 121 Appendix D(a); Part 1 - Agenda Item L-63.

7-79. By adding a new Sec. 121.292 to read as follows:

Sec. 121.292 Evacuation alarm system.
After (a date one year after the effective date of this amendment), no person may operate a passenger-carrying airplane unless it is equipped with an evacuation alarm system that meets the requirements of Sec. 25.802.

Explanation. See the explanation for Sec. 25.802.
Ref. Proposal No. 510; FAR 121; Part 1 - Agenda Item L-65.

7-80. By revising Sec. 121.309(a) and (b)(3) to read as follows:

Sec. 121.309 Emergency equipment.
(a) General.
(1) No person may operate an airplane unless it is equipped with the emergency equipment listed in this section and in Sec. 121.310.
(2) After (a date one year from the effective date of this amendment) each public address system microphone intended for flight attendant use and each required item of emergency equipment such as fire extinguishers, portable oxygen bottles, and first-aid kits must be positioned adjacent to each flight attendant seat and be readily accessible to the seated flight attendant. No equipment may be located so as to adversely affect the safety of the flight attendant under any condition.
(3) All stowage compartments and containers must be placarded to indicate their contents.
(b) * * *
(3) Must be clearly identified and, when its mode of operation would not be obvious to each adult airplane occupant, it must be clearly marked with operating instructions located on or near the equipment; and
* * * * *

Explanation. See the proposal for Sec. 25.1411. This proposal would require Part 121 operators to comply with the requirements specified in the proposed revision to Sec. 25.1411(a), (b) and (h).
Ref. Proposal No. 525; Sec. 121.309(b); Part 1 - Agenda Item O-97.

7-78. By revising Sec. 121.310(a) and adding new Secs. 121.310(d)(4) and (l) to read as follows:

Sec. 121.310 Additional emergency equipment.
(a) Means for emergency evacuation. Except as provided in paragraph (a)(6) of this section, each passenger carrying landplane emergency exit (other than over-the-wing) that is more than six feet from the ground with the airplane on the ground and the landing gear extended, must have an approved means to assist the occupants in descending to the ground. In addition, the following apply:
(1) For any airplane for which the application for the type certificate as filed on or before April 30, 1972, the assisting means for the floor-level emergency exit must meet the requirements of Sec. 25.809)(f)(1) of this chapter in effect on April 30, 1972.
(2) For any airplane for which the application for type certificate was filed after April 30, 1972, but before (a date one day before two years after the effective date of this amendment), the assisting means must meet the requirements under which the airplane was type certificated.
(3) After (a date two years after the effective date of this amendment) the assisting means must meet the requirements of Sec. 25.809(f)(12) of this chapter in effect on (the effective date of this amendment).
(4) All assisting means that deploy automatically must be armed during taxiing, takeoffs, and landings.
(5) With respect to paragraph (a)(1) of this section, if the Administrator finds that the design of the exit makes compliance with Sec. 25.809(f)(1) impractical, he may grant a deviation from the requirement of automatic deployment if the assisting means automatically erects upon deployment and, with respect to required emergency exits, if an emergency evacuation demonstration is conducted in accordance with Sec. 121.291(a).
(6) Paragraph (a) of this section does not apply to the rear window emergency exit for DC-3 airplanes operated with less than 36 occupants, including crewmembers and less than five exits authorized for passenger use.
* * * * *
(d) * * *
(4) In addition to showing compliance with paragraph (d)(2) of this section, after (a date one year after the effective date of this amendment) each light must have a cockpit control device that has an "on", "off", and "armed" position.
* * * * *
(1) Portable lights. After (a date one year after the effective date of this amendment) no person may operate a passenger-carrying airplane unless it is equipped with portable self-powered high intensity emergency lights, installed so that at least one light is readily accessible from each flight attendant seat.

Explanation. The proposal for Sec. 121.310(a) would make the emergency evacuation slide requirements of the new proposed Sec. 25.809(f)(1) effective, for existing aircraft, two years after the date of this amendment. The addition of Sec. 121.310(d)(4) would expand the existing rule with respect to the function of the control device for the emergency lighting system. This may require retrofit of aircraft within one year from the effective date of this amendment.
See the proposal to add a new Sec. 25.812(1) for the proposed addition of a new Sec. 121.310(1).
Ref. Proposal Nos. 526, 1090; Sec. 121.310, Sec. 121.310(d)(2)(iii); Part 1 - Agenda Item L-71, L-72.

7-82. By revising Sec. 121.319(b)(1) to read as follows:

Sec. 121.319 Crewmember interphone system.
* * * * *
(b) * * *
(1) It must provide a means of two-way communication between the pilot compartment and all the galleys and other flight attendants stations;
* * * * *

Explanation. This proposal clarifies the present rule by specifically requiring interphone terminals in all the galleys and at all other flight attendant stations.
Ref. Proposal No. 240; Sec. 25.789; Part 1 - Agenda Item K-57.

7-33. By adding a sentence to Sec. 121.339(a)(2) to read as follows:

Sec. 121.339 Emergency equipment for extended overwater operation.
(a) * * *
(2) * * *. The liferafts provided must have sufficient seating capacity and buoyancy to accommodate the occupants of the airplane after the loss of one raft of the largest rated capacity or excess rafts must be provided for that purpose.
* * * * *

Explanation. The life raft requirements of Sec. 25.1415(b)(1) provide for the loss of one raft of the largest rated capacity whereas the current Sec. 121.339(a)(2) only requires rafts of rated capacities to accommodate all occupants of the airplane. This proposal would update the requirements of Part 121.
Ref. Proposal No. 1094; Sec. 121.339(a)(2); Part 1 - Agenda Item O-85.

APPENDIX D. [AMENDED]

7-84. By deleting paragraph (a) of Appendix D to Part 121 and marking it "[Reserved]".
Explanation. This proposal is related to the proposal for Sec. 121.291. The purpose is to relocate the evacuation performance requirements of that paragraph into Sec. 25.803(c). This would require the manufacturer to demonstrate the design in accordance with the similar evacuation conditions as the aircraft operators must now demonstrate their emergency procedures.
Ref. Proposal Nos. 523, 1096; Sec. 121.291, FAR 121; Appendix D; Part 1 - Agenda Items LP-62, L-64.

APPENDIX I COMMITTEE III (AIRFRAME) PROPOSALS DEFERRED - GROUP I

Based upon the discussions at the Airworthiness Review Conference, the FAA has determined that the proposals listed below appear to have sufficient merit to warrant further consideration but for various reasons should be deferred for consideration at the next Airworthiness Review or Operations Review as appropriate. Included in the reasons for deferral are the following:
1. The proposal is so complex or extensive that more time is required than is available within the 1974-75 Airworthiness Review to give it full consideration.
2. More data is needed to supplement or support the proposal, before a decision can be reached.
3. The proposal would be more appropriately considered during an operations review.
The deferral of these proposals does not foreclose the FAA from taking earlier separate rulemaking action on the deferred proposals if a need for such action should arise.

14 CFR (FAR Sec.)
Proposal No.
Comm. III
Agenda Item
Proponent
23.781
93
Part 2
G-28
General Aviation Manufacturers Association.
23.1419
126
do
H-35
Do.
Part 25
342
Part 1
G-25
National Aeronautics and Space Administration.
Part 25
147
do
K-61
Air Line Pilots Association.
Part 25
148
do
K-61
Air Line Pilots Association, Steward and Stewardesses.
Part 25
343
do
O-88
General Aviation Manufacturers Association.
Appendix C.
25.301
184
do
C-11
Joint Airworthiness Requirements Committee.
25.303
185
do
A-1
Aerospace Industries Association.
25.337
191
do
B-8
Joint Airworthiness Requirements Committee.
25.479
202
do
E-16
Do.
25.483
204
do
E-17
Do.
25.511
208
do
E-22
Do.
25.571
210
do
G-24
Do.
25.677
222
do
I-38
Do.
25.683
223
do
I-39
Do.
25.683
224
do
I-39
Aerospace Industries Association.
25.697
226
do
I-41
Joint Airworthiness Requirements Committee.
25.733
230
do
J-45
Do.
25.735
231
do
J-46
Do.
25.781
234
do
K-48
Do.
27.501
354
Part 2
A-2
Aerospace Industries Association.
27.571
357
do
A-4
Department of Transportation - Australia.
29.501
388
do
A-2
Aerospace Industries Association.
29.571
391
do
A-4
Department of Transportation - Australia.
29.811
396
do
B-8
Aerospace Industries Association.
135.151
551
do
G-30
Air Line Pilots Association.

GROUP 2

The following proposals are being deferred to be dealt with in a later notice as a part of this Airworthiness Review Program:

14 CFR (FAR Sec.)
Proposal No.
Comm. III
Agenda Item
Proponent
23.347
81
Part 2
C-15
General Aviation Manufacturers Association.
23.361
616
do
C-16
Federal Aviation Administration.
23.371
617
do
C-17
Do.
23.621
622
do
D-20
Do.
23.621
84
do
D-20
General Aviation Manufacturers Association.
23.625
85
do
D-18
Department of Transportation - Australia.
23.629
87
do
D-21
General Aviation Manufacturers Association.
23.677
88
do
E-22
Do.
23.679
626
do
E-23
Federal Aviation Administration.
23.729
90
do
F-24
National Transportation Safety Board.
23.729
627
do
F-24
Federal Aviation Administration.
23.735
630
do
F-25
Do.
23.735
629
do
F-25
Do.
23.773
632
do
G-27
Do.
23.773
92
do
G-27
General Aviation Manufacturers Association.
23.783
633
do
G-29
Federal Aviation Administration.
23.841
636
do
H-31
Do.
Part 25
146
Part 1
K-60
National Transportation Safety Board.
25.305
187
do
A-3
Aerospace Industries Association.
25.307
188
do
A-4
Joint Airworthiness Requirements Committee.
25.307
1047
do
A-4
Federal Aviation Administration.
25.335
190
do
B-7
Joint Airworthiness Requirements Committee.
25.341
192
do
A-2
Do.
25.365
197
do
C-12
Do.
25.365
198
do
C-12
Air Line Pilots Association.
25.365
1051
do
C-12
Federal Aviation Administration.
25.365
1051-1
do
C-12
Aerospace Industries Association.
25.427
199
do
D-13
Joint Airworthiness Requirements Committee.
25.445
200
do
D-14
Do.
25.473
201
do
E-15
Do.
25.479
1053
do
E-16
Federal Aviation Administration.
25.492
1055
do
E-19
Federal Aviation Administration.
25.493
206
do
E-20
Joint Airworthiness Requirements Committee.
25.571
211
do
G-24
Aerospace Industries Association.
25.571
1058
do
G-24
Federal Aviation Administration.
25.619
216
do
H-30
Joint Airworthiness Requirements Committee.
25.621
217
do
H-31
Do.
25.621
1062
do
H-31
Federal Aviation Administration.
25.631
218
do
H-33
General Aviation Manufacturers Association.
25.631
219
do
H-33
Joint Airworthiness Requirements Committee.
25.633
1665
do
H-34
Federal Aviation Administration.
25.671
559
do
I-35
Joint Airworthiness Requirements Committee.
25.672
221
do
I-36
Do.
25.677
1067
do
I-38
Federal Aviation Administration.
25.685
1068
do
I-40
Do.
25.729
229
do
J-44
Joint Airworthiness Requirements Committee.
25.783
1074
do
K-49
Federal Aviation Administration.
25.785
235
do
K-50
Joint Airworthiness Requirements Committee.
25.785
236
do
K-51
Air Line Pilots Association, Steward and Stewardesses.
25.785
237
do
K-52
National Transportation Safety Board.
25.785
238
do
K-51
Air Line Pilots Association, Steward and Stewardesses.
25.785
1077
do
K-50
Federal Aviation Administration.
25.787
239
do
K-56
Joint Airworthiness Requirements Committee.
25.787
1078
do
K-56
Federal Aviation Administration.
25.791
241
do
K-58
Joint Airworthiness Requirements Committee.
25.799
242
do
K-59
Do.
25.807
247
do
L-66
Do.
25.819
728
do
L-74
Federal Aviation Administration.
25.843
255
do
M-75
Joint Airworthiness Requirements Committee.
25.851
256
do
Not in agenda
Aerospace Industries Association.
25.853
257
Part 1
N-76
Rijksluchtvaartdienst, Netherlands.
25.853
731
do
N-77
Federal Aviation Administration.
25.853
145
do
N-77
National Transportation Safety Board.
25.853
259
do
N-76
Aerospace Industries Association.
25.855
260
do
N-78
Air Line Pilots Association, Steward and Stewardesses.
25.857
261
do
N-79
Joint Airworthiness Requirements Committee.
25.857
733
do
N-79
Federal Aviation Administration.
25.863
262
do
N-80
Joint Airworthiness Requirements Committee.
25.1415
315
do
O-86
Air Transport Association.
25.1421
807
do
N-81
Federal Aviation Administration.
27.521
355
Part 2
A-3
Aerospace Industries Association.
27.621
358
do
B-5
Do.
27.621
845
do
B-5
Federal Aviation Administration.
29.351
387
do
Not in agenda
Aerospace Industries Association.
29.521
389
Part 2
A-3
Do.
29.621
392
do
B-5
Do.
29.621
901
do
B-5
Federal Aviation Administration.
37.175
1002
Part 1
O-85
Do.
Part 91
482
do
K-53
National Transportation Safety Board.
91.193
1017
do
N-82
Federal Aviation Administration.
91.197
1018
do
K-58
Do.
Part 121
512
do
N-77
National Transportation Safety Board.
Part 121
513
do
K-54
Do.
121.198
520
do
O-91
Consulting Aerospace Engineers, Inc.
121.215
522
do
N-76
Air Transport Association.
121.312
1091
do
N-76
Federal Aviation Administration.
121.321
529
do
K-52
National Transportation Safety Board.
121.321
1092
do
K-55
Federal Aviation Administration.
121.339
533
do
O-86
Air Transport Association.

APPENDIX II COMMITTEE III (AIRFRAME) PROPOSALS WITHDRAWN BY PROPONENT
The proposals listed below were withdrawn by their proponents. The proponents or other interested persons may submit similar proposals in the future. The withdrawal of FAA proposals does not commit the FAA to any future course of action.

14 CFR (FAR Sec.)
Proposal No.
Comm. III
Agenda Item
Proponent
25.613
214
Part 1
H-28
Joint Airworthiness Requirements Committee.
25.615
215
do
H-29
Do.
25.675
1066
do
I-37
Federal Aviation Administration.
25.735
1070
do
J-46
Do.
25.773
1073
do
K-47
Do.
25.783
1075
do
K-49
Do.
25.813
724
do
L-73
Do.
25.1307
786
do
O-83
Do.
27.1419
875
Part 2
B-13
Do.
29.365
896
do
A-1
Do.
29.841
908
do
A-1
Do.
29.843
909
do
A-1
Do.
29.1419
959
do
B-13
Do.



Hide details for Footer InformationFooter Information
Issued in Washington, DC, on June 9, 1975.
[FR Doc. 75-14883 Filed 6-9-75; 8:45 am]

Hide details for CommentsComments
This NPRM did not show an "Issued Date" in the Federal Register. The AIR National Librarian used the filed date from the Federal Register in the "Issued Date" field.

Hide details for Document HistoryDocument History

Other Notice of Proposed Rulemaking Actions:

Notice of Invitation to Submit Proposals; Notice No. 74-5; Issued on 2/14/74.
Notice of Compilation of Proposals; Notice No. 74-5A; Issued on 5/22/74.
Notice of Availability of Agenda; Notice No. 74-5B; Issued on 10/3/74.
Notice of Clarifying Revisions; Notice No. 74-33; Issued on 10/3/74.
Notice of Conference; Notice No. 74-5C; Issued on 11/25/74.
Notice of Availability of Conference Summary; Notice No. 74-5D; Issued on 2/4/75.
Notice of Airworthiness Review Program No. 2; Notice No. 75-10; Issued on 2/27/75.
Notice of Airworthiness Review Program No. 3; Notice No. 75-19; Issued on 5/13/75.
Notice of Airworthiness Review Program No. 4; Notice No. 75-20; Issued on 5/13/75.
Notice of Airworthiness Review Program No. 5; Notice No. 75-23; Issued on 5/19/75.
Notice of Airworthiness Review Program No. 6; Notice No. 75-25; Issued on 5/29/75.
Notice of Airworthiness Review Program No. 8; Notice No. 75-31; Issued on 6/30/75.

Final Rule Actions:

Final Rule. Docket No. 14324; Issued on 12/13/76.
Final Rule. Docket No. 14625; Issued on 07/11/77.
Final Rule. Docket No. 14324, 14606, 14625, 14685, 14779; Issued on 10/20/78.
Final Rule. Docket No 14779, 14324; Issued on 8/27/80.