[Federal Register Volume 62, Number 116 (Tuesday, June 17, 1997)]
[Notices]
[Pages 32852-32854]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-15860]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration


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 and request for comments.

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SUMMARY: This notice requests comments regarding proposed revisions to 
Advisory Circular (AC) 25-7, ``Flight Test Guide for Certification of 
Transport Category Airplanes.'' AC 25-7 provides guidance on acceptable 
means, but not the only means, of demonstrating compliance with the 
airworthiness standards for transport category airplanes. The proposed 
revisions complement revisions to the airworthiness standards for 
transport category airplanes that were proposed recently by separate 
notice in the Federal Register. This notice provides interested persons 
an opportunity to comment on the proposed revisions to the AC 
concurrently with the proposed rulemaking.

DATES: Comments must be received on or before September 8, 1997.

ADDRESSES: Send all comments on the proposed AC revisions to the 
Federal Aviation Administration, Attention: Don Stimson, Flight Test 
and Systems 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 
4:00 p.m. weekdays, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Patricia Siegrist, Regulations Branch, 
ANM-114, at the above address, telephone (425) 227-2126, or facsimile 
(425) 227-1320.

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.

[[Page 32853]]

Discussion

    On June 9, 1997, the Federal Aviation Administration (FAA) 
published a proposal (Notice 97-9, 62 FR 31482) to amend 14 CFR part 25 
to revise the requirements regarding gated positions on the control 
used by the pilot to select the position of an airplane's high-lift 
devices. The proposed amendment would update the current standards to 
take into account the multiple configurations of the high-lift devices 
provided on current airplanes to perform landings and go-around 
maneuvers. The proposed amendment would also harmonize these standards 
with those being proposed for the European Joint Aviation Requirements 
(JAR-25).
    The FAA also proposes to revise Advisory Circular (AC) 25-7, 
``Flight Test Guide for Certification of Transport Category 
Airplanes,'' to provide additional guidance and criteria for locating 
the gate when the airplane has multiple go-around configurations. This 
proposed revision to AC 25-7 should not be confused with other proposed 
revisions of AC 25-7 for which the FAA is currently seeking comments. 
This revision only addresses guidance material associated with gated 
positions on the control used by the pilot to select the position of an 
airplane's high-lift devices. Issuance of a revised AC based on this 
proposal is contingent on adoption of the revisions to part 25 proposed 
in Notice 97-9.
    Through an inadvertent publication error, this AC notice was not 
published in the same issue of the Federal Register as Notice 97-9 and 
is therefore being published at this time to allow the public the 
opportunity to comment on the AC concurrently with the rulemaking 
proposed in Notice 97-9.

Revisions to AC 25-7 Which Accompany Notice 97-9

    1. Revise paragraph 21a(2) as follows:
    (2) Section 25.145(b) requires changes to be made in flap position, 
power, and speed without undue effort when retrimming is impractical. 
The purpose is to ensure that any of these changes are possible 
assuming that the pilot finds it necessary to devote at least one hand 
to the initiation of the desired operation without being overpowered by 
the primary airplane controls. The objective is to show that an 
excessive change in trim does not result from the application of power 
or the extension or retraction of wing flaps. The presence of gated 
positions on the flap control does not affect the requirement to 
demonstrate full flap extensions and retractions without changing the 
trim control. Compliance with Sec. 25.145(b) also requires that the 
relation of control force to speed be such that reasonable changes in 
speed may be made without encountering very high control forces.
    2. Revise paragraphs 21a(3) as follows:
    (3) Section 25.145(c) contains requirements associated primarily 
with attempting a go-around maneuver from the landing configuration. 
Retraction of the high-lift devices from the landing configuration 
should not result in a loss of altitude if the power or thrust controls 
are moved to the go-around setting at the same time that flap/slat 
retraction is begun. The design features involved with this requirement 
are the rate of flap/slat retraction, the presence of any flap gates, 
and the go-around power or thrust setting. The go-around power or 
thrust setting should be the same as is used to comply with the 
approach and landing climb performance requirements Secs. 25.121(d) and 
25.119, and the controllability requirements of Secs. 25.145(b)(3), 
25.145(b)(4), 25.145(b)(5), 25.149(f), and 25.149(g). The 
controllability requirements may limit the go-around power or thrust 
setting.
    4. Add a new paragraph 21a(4) to read as follows:
    (4) Section 25.145(d)  provides requirements for demonstrating 
compliance with Sec. 25.145(c) when gates are installed ion the flap 
selector. Section 25.145(d) also specifies gate design requirements. 
Flap gates, which prevent the pilot from moving the flap selector 
through the gated position without a separate and distinct movement of 
the selector, allow compliance with these requirements to be 
demonstrated in segments. High lift device retraction must be 
demonstrated beginning from the maximum landing position to the first 
gated position, between gated positions, and from the last gated 
position to the fully retracted position.
    (i) If gates are provided, Sec. 25.145(d) requires the first gate 
from the maximum landing position to be located at a position 
corresponding to a go-around configuration. If there are multiple go-
around configurations, the following criteria should be considered when 
selecting the location of the gate:
    (A) The expected relative frequency of use of the available go-
around configurations.
    (B) The effects of selecting the incorrect high-lift device control 
position.
    (C) The potential for the pilot to select the incorrect control 
position, considering the likely situations for use of the different 
go-around positions.
    (D) The extent to which the gate(s) aid the pilot in quickly and 
accurately selecting the correct position of the high-lift devices.
    (ii) Regardless of the location of any gates, initiating a go-
around from any of the approved landing positions should not result in 
a loss of altitude. Therefore, Sec. 25.145(d) requires that compliance 
with Sec. 25.145(c) be demonstrated for retraction of the high-lift 
devices from each approved landing position to the control position(s) 
associated with the high-lift device configuration(s) used to establish 
the go-around procedure(s) from that landing position. A separate 
demonstration of compliance with this requirement should only be 
necessary if there is a gate between an approved landing position and 
its associated go-around position(s). If there is more than one 
associated go-around position, conducting this test using the go-around 
configuration with the most retracted high-lift device position should 
suffice, unless there is a more critical case. If there are no gates 
between any of the landing flap positions and their associated go-
around positions, the demonstrations discussed in paragraph 21a(4) 
above should be sufficient to show compliance with this provision of 
Sec. 25.145(d).
    5. Revise paragraph 21c(6) as follows:
    (6) Longitudinal control, flap retraction and power application, 
Secs. 25.145(c) and (d).
    6. Revise paragraph 21c(6)(ii) as follows:
    (ii) With the airplane stable in level flight at a speed of 1.1 
VS for propeller driven airplanes, or 1.2 VS for 
turbojet powered airplanes, retract the flaps to the full up position, 
or the next gated position, while simultaneously setting go-around 
power. Use the same power or thrust as is used to comply with the 
performance requirement of Sec. 25.121(d), as limited by the applicable 
controllability requirements. It must be possible, without requiring 
exceptional piloting skill, to prevent losing altitude during the 
maneuver. Trimming is permissible at any time during the maneuver. If 
gates are provided, conduct this test from the maximum landing flap 
position to the first gate, from gate to gate, and from the last gate 
to the fully retracted position. If there is a gate between any landing 
position and its associated go-around position(s), this test should 
also be conducted from that landing position through the gate to the 
associated go-around position. If there is more than one associated go-
around position, this additional test should be conducted using the go-
around position corresponding to the most retracted flap

[[Page 32854]]

position, unless another position is more critical. Keep the landing 
gear extended throughout the test.

    Issued in Renton, Washington, on June 10, 1997.
Stewart R. Miller,
Manager, Transport Standards Staff, Transport Airplane Directorate, 
Aircraft Certification Service, ANM-100.
[FR Doc. 97-15860 Filed 6-16-97; 8:45 am]
BILLING CODE 4910-13-M