[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
