[Federal Register Volume 59, Number 131 (Monday, July 11, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-16535]


[[Page Unknown]]

[Federal Register: July 11, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-61-AD; Amendment 39-8970; AD 94-14-21]

 

Airworthiness Directives; Boeing Model 747-400 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747-400 series airplanes, that 
requires a revision to the Flap Control Unit input wiring. This 
amendment 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 this AD are intended to prevent the possibility of an all-
flaps-up landing due to the loss of control of all flap operations.

DATES: Effective August 10, 1994. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of August 10, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. This information may be examined at the Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of 
the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain Boeing Model 747-400 
series airplanes was published in the Federal Register on May 12, 1994 
(59 FR 24671). That action proposed to require a revision to the Flap 
Control Unit (FCU) input wiring.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter, Boeing, requests that the discussion of the 
addressed unsafe condition that appeared in the preamble to the notice 
be clarified. In that preamble, the FAA stated that, if the landing 
gear module connectors become disconnected, all FCU modes of flap 
operation (primary, secondary, and alternate control of flaps) could be 
lost. The commenter suggests that the discussion would have been more 
precise if it had contained information to indicate that the landing 
gear module includes the ALTN ARM FLAPS switch and the ALTN FLAPS 
position selector used to control the leading and trailing edge flaps 
in the alternate mode. The FAA acknowledges this information.
    This same commenter requests that the proposal be revised to cite 
the latest revision of Boeing Service Bulletin 747-27A2346 as the 
source for modification procedures. The FAA concurs. Since issuance of 
the notice, the FAA has reviewed and approved Revision 1 of Boeing 
Service Bulletin 747-27A2346, dated May 19, 1994. This revision 
contains a correction to a type of wire that had been called out in the 
original version of the service bulletin; this correction ensures that 
the wire and its associated solder sleeve are metalurgically 
compatible. In order to ensure that the correct wiring modification 
assembly is installed on the affected airplanes, the FAA has determined 
that the revised service bulletin should be cited as the appropriate 
source of service information for complying with the requirements of 
this rule. The final rule has been revised accordingly. The FAA has 
confirmed that no U.S. operators have yet modified any affected 
airplane in accordance with the original service bulletin; therefore, 
by citing the revised service bulletin, the final rule will impose no 
additional economic burden on any U.S. operator.
    One commenter requests that the compliance time be extended from 
the proposed 30 days to 90 days, due to a possible parts availability 
problem. This commenter states that it does not normally stock the 
required parts and materials to accomplish the proposed requirements of 
the rule. This commenter has ordered these parts from a supplier and is 
currently waiting to obtain them. Additionally, this commenter points 
out that the manufacturer's service bulletin, referenced in the 
proposal, recommends 60 days for modification. The FAA does not concur 
with the commenter's request. In developing an appropriate compliance 
time for this action, the FAA considered not only the degree of urgency 
associated with addressing the subject unsafe condition, but the 
manufacturer's recommendation as to an appropriate compliance time, the 
availability of required parts, and the practical aspect of installing 
the required modification within a maximum interval of time allowable 
for all affected airplanes to continue to operate without compromising 
safety. The FAA points out that the parts required for the wiring 
modification are readily available; therefore, obtaining them within 
the proposed compliance time should not pose a problem for any affected 
operator. Further, the FAA took into account the 60-day compliance time 
recommended by the manufacturer, as well as the number of days required 
for the rulemaking process; in consideration of these factors, the FAA 
finds that 30 days after the effective date of this final rule will 
fall approximately at the same time for compliance as recommended by 
the manufacturer. However, under the provisions of paragraph (b) of the 
final rule, the FAA may approve requests for adjustments to the 
compliance time if data are submitted to substantiate that such an 
adjustment would provide an acceptable level of safety.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    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 will be affected by this AD, that it will 
take approximately 10 work hours per airplane to accomplish the 
required actions, and that the average labor rate is $55 per work hour. 
Required parts will cost approximately $200 per airplane. Based on 
these figures, the total cost impact of the 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 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action: (1) Is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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.


Sec. 39.13  [Amended]

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

94-14-21  Boeing: Amendment 39-8970. 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, Revision 1, dated May 19, 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.
    (d) The wiring revision shall be done in accordance with Boeing 
Alert Service Bulletin 747-27A2346, Revision 1, dated May 19, 1994. 
This incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Boeing Commercial Airplane Group, 
P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be 
inspected at the FAA, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington; or at the Office of the Federal 
Register, 800 North Capitol Street NW., suite 700, Washington, DC.
    (e) This amendment becomes effective on August 10, 1994.

    Issued in Renton, Washington, on July 1, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-16535 Filed 7-8-94; 8:45 am]
BILLING CODE 4910-13-U