[Federal Register Volume 60, Number 31 (Wednesday, February 15, 1995)]
[Proposed Rules]
[Pages 8591-8593]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-3752]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-NM-251-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 supersedure of an existing 
airworthiness directive (AD), applicable to certain Boeing Model 747-
400 series airplanes, that currently requires a revision to the input 
wiring for the flap control unit. This action would require a new 
systems test for the wiring of the trailing edge flap. The proposal 
would also expand the applicability of the existing AD to include 
additional airplanes. This proposal is prompted by a report indicating 
that a wiring error was not detected by the system test required by the 
existing AD. 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 April 10, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
[[Page 8592]] Attention: Rules Docket No. 94-NM-251-AD, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected 
at this location between 9:00 a.m. and 3:00 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: Kristin Larson, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, Seattle Aircraft Certification 
Office, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056; telephone (206) 227-1760; 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-251-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-251-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On July 1, 1994, the FAA issued AD 94-14-21, amendment 39-8970 (59 
FR 35240, July 11, 1994), applicable to certain Boeing Model 747-400 
series airplanes, to require a revision to the input wiring for the 
flap control unit (FCU). That action was 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 requirements of that AD are intended to prevent the 
possibility of an all-flaps-up landing due to the loss of control of 
all flap operations.
    Since issuance of that AD, an operator has reported a wiring error 
of the Landing Gear Module that was not detected by the system test 
(Work Package I) required by AD 94-14-21, and described in Boeing 
Service Bulletin 747-27A2346, Revision 1, dated May 19, 1994. This 
wiring error could allow the connectors to become disconnected, and all 
FCU modes of flap operation (primary, secondary, and alternate control 
of flaps) could be lost. This condition, if not corrected, could result 
in all-flaps-up landing due to the loss of control of all flap 
operations.
    The FAA has reviewed and approved Boeing Service Bulletin 747-
27A2346, Revision 2, dated January 12, 1995, which provides procedures 
for a systems test (Work Package II) of the trailing edge flap to 
detect incorrect wiring. It also expands the effectivity listing to 
include additional affected airplanes.
    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 supersede AD 94-14-21 to continue to require revision 
of the input wiring for the flap control unit, but would include the 
addition of a new systems test for the wiring of the trailing edge 
flap. The proposed AD also would expand the applicability of the 
existing AD to include additional airplanes. The actions would be 
required to be accomplished in accordance with the service bulletin 
described previously.
    As a result of recent communications with the Air Transport 
Association (ATA) of America, the FAA has learned that, in general, 
some operators may misunderstand the legal effect of AD's on airplanes 
that are identified in the applicability provision of the AD, but that 
have been altered or repaired in the area addressed by the AD. The FAA 
points out that all airplanes identified in the applicability provision 
of an AD are legally subject to the AD. If an airplane has been altered 
or repaired in the affected area in such a way as to affect compliance 
with the AD, the owner or operator is required to obtain FAA approval 
for an alternative method of compliance with the AD, in accordance with 
the paragraph of each AD that provides for such approvals. A note has 
been included in this notice to clarify this requirement.
    There are approximately 310 Model 747-400 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 36 
airplanes of U.S. registry would be affected by this proposed AD, that 
it would take approximately .5 work hours per airplane to accomplish 
the proposed actions, and that the average labor rate is $60 per work 
hour. Based on these figures, the total cost impact of the proposed AD 
on U.S. operators is estimated to be $1,080, or $30 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. 
[[Page 8593]] 

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) 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.


39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-8970 (59 FR 
35240, July 11, 1994), and by adding a new airworthiness directive 
(AD), to read as follows:

Boeing: Docket 94-NM-251-AD. Supersedes AD 94-14-21, Amendment 39-
8970.

    Applicability: Model 747-400 series airplanes having line 
numbers 696 through 1036 inclusive; certificated in any category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must use the authority 
provided in paragraph (d) to request approval from the FAA. This 
approval may address either no action, if the current configuration 
eliminates the unsafe condition; or different actions necessary to 
address the unsafe condition described in this AD. Such a request 
should include an assessment of the effect of the changed 
configuration on the unsafe condition addressed by this AD. In no 
case does the presence of any modification, alteration, or repair 
remove any airplane from the applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.

    Note 2: Paragraph (a) of this AD merely restates the 
requirements of paragraph (a) of AD 94-14-21, amendment 39-8970. As 
allowed by the phrase, ``unless accomplished previously,'' if those 
requirements of AD 94-14-21 have already been accomplished, this AD 
does not require that those actions be repeated.

    To prevent the possibility of an all-flaps-up landing due to the 
loss of control of flap operations, accomplish the following:
    (a) For airplanes having serial numbers 696 through 1019 
inclusive, and 1021 through 1026 inclusive: Within 30 days after 
August 10, 1994 (the effective date of AD 94-14-21, amendment 39-
8970), revise the input wiring for the flap control unit (FCU) in 
accordance with Boeing Service Bulletin 747-27A2346, Revision 1, 
dated May 19, 1994, or Revision 2, dated January 12, 1995.
    (b) For airplanes having serial numbers 1020, and 1027 through 
1036 inclusive: Within 30 days after the effective date of this AD, 
revise the input wiring for the FCU in accordance with Boeing 
Service Bulletin 747-27A2346, Revision 2, dated January 12, 1995.
    (c) For airplanes having serial numbers 696 through 1036 
inclusive: Within 120 days after the effective date of this AD, 
perform the additional systems test for the wiring of the trailing 
edge flap in accordance with Boeing Service Bulletin 747-27A2346, 
Revision 2, dated January 12, 1995.
    (d) 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 Aircraft 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (e) 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 February 9, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-3752 Filed 2-14-95; 8:45 am]
BILLING CODE 4910-13-U