02-1003. Proposed Revisions to Advisory Circular-Flight Test Guide for Certification of Transport Category Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed advisory circular revision and request for comments.

SUMMARY:

This notice requests comments regarding proposed revisions to Advisory Circular (AC) 25-7A, “Flight Test Guide for Certification of Transport Category Airplanes.” This AC provides guidance on acceptable means, but not the only means, of demonstrating compliance with certain airworthiness standards for transport category airplanes. The proposed revisions to the AC complement proposed revisions to the airworthiness standards for transport category airplanes, published by separate document in the Federal Register on January 14, 2002 (67 FR 1846). This notice provides interested persons an opportunity to comment on the proposed revisions to the AC concurrently with the proposed rulemaking. Like all ACs, it is not mandatory, but is to provide guidance for applicants in demonstrating compliance with the objective safety standards set forth in the related rule.

DATES:

Comments must be received by April 1, 2002.

ADDRESSES:

Send all comments on the proposed AC revisions to the Federal Aviation Administration, Attention: Don Stimson, Airplane and Flight Crew Interface Branch, ANM-111, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Ave. SW., Renton, WA 98055-4056. Comments may be examined at the above address between 7:30 a.m. and 4 p.m. weekdays, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Susan Boylon, Program Management Branch, ANM-114, at the above address, telephone [phone], or facsimile [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to comment on the proposed revisions to the AC by submitting such written data, views, or arguments, as they may desire. Commenters must identify the title of the AC and submit comments in duplicate to the address specified above. All comments received on or before the closing date for comments will be considered by the Transport Airplane Directorate before issuing the revised AC.

Discussion

In a separate document published in the Federal Register on January 14, 2002 (67 FR 1846), the FAA proposes to amend the airworthiness standards for transport category airplanes concerning miscellaneous flight requirements. We initiated the proposal under the “Fast Track Harmonization Program” November 26, 1999 (64 FR 66522). Adopting that proposal would eliminate regulatory differences between the airworthiness standards of the U.S. and the Joint Aviation Requirements of Europe, without affecting current industry design practices.

In addition to the amendments proposed in Notice 02-01, the FAA also proposes to revise Advisory Circular (AC) 25-7A, “Flight Test Guide for Certification of Transport Category Airplanes,” to provide additional guidance concerning takeoff path, lateral control, trim (longitudinal), trim (airplanes with four or more engines), and demonstration of static longitudinal stability. This proposed revision to AC 25-7A should not be confused with other proposed revisions of AC 25-7A on which the FAA is currently seeking comments. This revision only addresses guidance material associated with these specific airworthiness requirements. Issuance of a revised AC based on this proposal is contingent on adoption of the revisions to part 25 in Notice 02-01.

Proposed Revisions to AC 25-7A

1. Add a new paragraph, 12a(1)(iii) to read as follows:

(iii) The height references in § 25.111 should be interpreted as geometrical heights.

2. Revise paragraph 12e(2) to read as follows:

(2) Procedures. The time between liftoff and the initiation of gear retraction during takeoff distance demonstrations should not be less than that necessary to establish an indicated positive rate of climb plus one second. For the purposes of flight manual expansion, the average demonstrated time delay between liftoff and initiation of gear retraction may be assumed; however, this value should not be less than 3 seconds.

3. Revise paragraph 22a(2) to read as follows:

(2) Sections 25.147(c) and (e) require an airplane to be easily controllable with the critical engine(s) inoperative. Section 25.147(d) further requires that lateral control be sufficient to provide a roll rate necessary for safety, without excessive control forces or travel, at the speeds likely to be used with one engine inoperative. Compliance can normally be demonstrated in the takeoff configuration at V₂ speed, because this condition is usually the most critical. Normal operation of a yaw stability augmentation system (SAS) should be considered in accordance with normal operating procedures. Roll response, § 25.147(e), should be satisfactory for takeoff, approach, landing, and high speed configurations. Any permissible configuration that could affect roll response should be evaluated.

4. Revise paragraph 22b as follows:

b. Procedures. The following test procedures outline an acceptable means for demonstrating compliance with § 25.147.

5. Revise paragraph 22b(4) to read as follows:

(4) Lateral Control—Roll Capability, § 25.147(d).

(i) Configuration:

(A) Maximum takeoff weight.

(B) Most aft c.g. position.

(C) Wing flaps in the most critical takeoff position.

(D) Landing gear retracted.

(E) Yaw SAS on, and off, if applicable.

(F) Operating engine(s) at maximum takeoff power.

(G) The inoperative engine that would be most critical for controllability, with the propeller feathered, if applicable.

(ii) Test Procedure: With the airplane in trim, or as nearly as possible in trim, for straight flight at V2, establish a steady 30 degree banked turn. It should be demonstrated that the airplane can be rolled to a 30 degree bank angle in the other direction in not more than 11 seconds. In this demonstration, the rudder may be used to the extent necessary to minimize sideslip. The demonstration should be made in the most adverse direction. The maneuver may be unchecked. Care should be taken to prevent excessive sideslip and bank angle during the recovery.

6. Revise paragraph 22b(4) by renumbering it as paragraph 22b(5) as follows:

(5) Lateral Control—Four or More Engines, § 25.147(e).

7. Revise paragraph 22b(5) by renumbering it as paragraph 22b(6) as follows:

(6) Lateral Control—All Engines Operating, § 25.147(f).

Issued in Renton, Washington, on December 19, 2001.

Ali Bahrami,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.