[Federal Register Volume 59, Number 91 (Thursday, May 12, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-11526]


[[Page Unknown]]

[Federal Register: May 12, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-61-AD]

 

Airworthiness Directives; Boeing Model 747-400 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-400 
series airplanes. This proposal would require a revision to the Flap 
Control Unit input wiring. This proposal is prompted by reports of 
disconnection of the Landing Gear Module electrical connectors, which 
can result in the loss of the primary, secondary, and alternate control 
of the flaps. The actions specified by the proposed AD are intended to 
prevent the possibility of an all-flaps-up landing due to the loss of 
control of all flap operations.

DATES: Comments must be received by June 13, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 94-NM-61-AD, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056. Comments may be inspected at this location 
between 9 a.m. and 3 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Kathi Ishimaru, Aerospace Engineer, 
Systems & Equipment Branch, ANM-130S, Seattle Aircraft Certification 
Office, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056; telephone (206) 227-2674; fax (206) 227-
1181.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-NM-61-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 94-NM-61-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    Boeing Commercial Airplanes has advised the FAA of an unsafe 
condition that may exist in certain Boeing Model 747-400 series 
airplanes. Boeing advises that, if the Landing Gear Module connectors 
become disconnected, all Flap Control Unit (FCU) modes of flap 
operation (primary, secondary, and alternate control of flaps) could be 
lost. There has been one occurrence of a partial disconnection of these 
connectors during a flight test of one airplane, which resulted in some 
of the flaps failing to extend. In another incident, there was a 
partial disconnection of these connectors on one in-service airplane 
that occurred while the airplane was on the ground; this situation 
prevented the airplane from being dispatched.
    Disconnection of the subject connectors could result in the loss of 
all three modes of flap operation. If this were to occur, the pilot 
would be unable to change the position of the leading and trailing edge 
flaps. This condition, if not corrected, could result in an all-flaps-
up (flaps retracted) landing and consequent high landing speeds that 
could cause the airplane to run off the runway before being able to 
stop.
    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-27A2346, dated April 28, 1994, that describes procedures for 
revising the FCU input wiring by moving two of the three FCU inputs 
from the ``Alt-Arm'' switch to the Alternate Flap relays. This will 
keep the FCU's in the Primary Hydraulic/Pneumatic operation mode if the 
Landing Gear Module connectors become disconnected, and would allow the 
pilot to maintain primary and secondary control of the flaps.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require revising the FCU input wiring. The actions 
would be required to be accomplished in accordance with the service 
bulletin described previously.
    There are approximately 300 Model 747-400 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 34 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately 10 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $55 per work 
hour. Required parts would cost approximately $200 per airplane. Based 
on these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $25,500, or $750 per airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the proposed 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The regulations proposed herein would not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, will not have a significant economic impact, 
positive or negative, on a substantial number of small entities under 
the criteria of the Regulatory Flexibility Act. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 14 
CFR part 39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

Boeing: Docket 94-NM-61-AD.

    Applicability: Model 747-400 airplanes having line numbers 696 
through 1019, inclusive, and 1021 through 1026, inclusive; 
certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the possibility of an all-flaps-up landing due to the 
loss of control of flap operations, accomplish the following:
    (a) Within 30 days after the effective date of this AD, revise 
the Flap Control Unit (FCU) input wiring in accordance with Boeing 
Alert Service Bulletin 747-27A2346, dated April 28, 1994.
    (b) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Seattle Aircraft Certification 
Office (ACO), FAA, Transport Airplane Directorate. Operators shall 
submit their requests through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Seattle ACO.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

    Issued in Renton, Washington, on May 6, 1994.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-11526 Filed 5-11-94; 8:45 am]
BILLING CODE 4910-13-U