AD Amdt-39-11051

[Federal Register Volume 64, Number 39 (Monday, March 1, 1999)]
[Rules and Regulations]
[Pages 9906-9908]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 99-4630]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-254-AD; Amendment 39-11051; AD 99-05-02]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 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 series airplanes, that requires 
a one-time detailed visual inspection of the outboard sequence carriage 
attachment fitting for the presence and condition of a shim and any 
loose fastener, and follow-on corrective actions, if necessary. This 
amendment is prompted by a report that a piece of the left wing inboard 
foreflap came off during a landing approach and struck and penetrated 
the airplane fuselage. The actions specified by this AD are intended to 
prevent the failure of the outboard sequence carriage fitting, which 
could allow the wing inboard foreflap to separate and penetrate the 
fuselage, possibly injuring passengers and crewmembers.

DATES: Effective April 5, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of April 5, 1999.

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

[[Page 9907]]

the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: Tamara L. Anderson, Aerospace 
Engineer, Airframe Branch, ANM-120S, FAA, Transport Airplane 
Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, 
SW., Renton, Washington 98055-4056; telephone (425) 227-2771; fax (425) 
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 series 
airplanes was published in the Federal Register on April 15, 1998 (63 
FR 18341). That action proposed to require a one-time detailed visual 
inspection of the outboard sequence carriage attachment fitting for the 
presence and condition of a shim, and follow-on corrective actions, if 
necessary.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Issuance of Proposed Rule Is Unwarranted

    One commenter considers that issuance of the proposed rule is 
unwarranted. The commenter states that the reason for the inspection of 
the outboard foreflap fitting is because an overhauled flap did not 
have a shim installed, which caused the foreflap to break apart during 
landing approach. The commenter also states that this condition caused 
damage to the aircraft fuselage, and a slight roll during flight, but 
no noticeable changes to the flight characteristics. The commenter 
points out that, although it is performing the inspections in 
accordance with Boeing Alert Service Bulletin 747-57A2302, dated April 
10, 1997, it does not agree that the inspection should be mandated for 
several reasons.
    First, the 747 Component Maintenance Manual (CMM) 57-52-31 clearly 
includes procedures for installation of the shim, which specify that 
the gap is not to exceed 0.003 inch. Second, although it appears that 
CMM procedures were not followed by the overhaul facility during 
overhaul of the foreflap that broke apart in flight, this is no reason 
to require all operators to perform the inspection. The commenter adds 
that, although individual operators occasionally make errors in 
approved maintenance procedures that require an operator to inspect its 
fleet for conformity to type certification, the FAA does not then 
require all operators to accomplish the same inspections as those of 
one errant operator. In addition, neither the alert service bulletin 
nor the NPRM provides any reason to believe that another operator or 
overhaul facility would have made the same error.
    The FAA does not concur that issuance of the proposed rule is 
unwarranted. The FAA has considered not only that the condition 
(excessive gap) may exist on other airplanes of the same type design, 
but also the consequences of this type of maintenance error. In 
addition, the FAA has determined that exceeding the specified gap 
(0.003 inch) on an installed fitting could result in puncturing the 
fuselage skin (adjacent to passenger seats) and injuring passengers and 
crewmembers. In light of this, the FAA considers that the actions 
required by this AD are necessary and that issuance of this final rule 
will ensure an adequate level of safety for the affected fleet.

Request To Correct the Applicability

    One commenter [the Civil Aviation Authority (CAA), which is the 
airworthiness authority for the United Kingdom], points out a 
contradiction in the proposed AD regarding the number of airplanes 
affected. The CAA states that the cost impact information of the 
proposal indicates that approximately 1,147 airplanes are affected, 
whereas the applicability of the proposal refers to line numbers 1 
through 1,122 inclusive.
    Another commenter states that the line number effectivity should be 
1 through 1,116, and that this change is included in Boeing Service 
Bulletin 747-57A2302, Revision 1, dated June 18, 1998. The commenter 
also reports that line numbers 1,117 through 1,122 were inspected at 
the manufacturer's facility prior to delivery.
    The FAA concurs with the commenters' requests to correct the 
applicability of this AD. The FAA has determined that it is appropriate 
to exclude those airplanes (line numbers 1,117 through 1,122) that have 
been inspected prior to delivery, and has confirmed that the 
effectivity of Revision 1 of the service bulletin includes line numbers 
1 through 1,116. The FAA has determined that there are 991 airplanes of 
the affected design in the worldwide fleet and 213 airplanes of U.S. 
registry that are affected by this AD. The cost impact information, 
below, has been revised accordingly. In addition, the FAA has revised 
the applicability of the final rule to indicate line numbers 1 through 
1,116 inclusive, instead of 1 through 1,122 inclusive.

Request To Correct a Typographical Error

    The CAA points out that, in the applicability of the proposed AD, 
the reference to ``47-100B'' should be ``747-100B.'' The FAA concurs. 
The final rule has been changed accordingly.

New Service Information

    Since issuance of the proposed AD, the FAA has reviewed and 
approved Boeing Service Bulletin 747-57A2302, Revision 1, dated June 
18, 1998. This new revision is essentially the same as the original 
issue of this service bulletin, which was cited in the proposed AD as 
the appropriate source of service information for accomplishment of the 
actions required. However, Revision 1 reduces the number of airplanes 
included in the service bulletin effectivity (as stated previously), 
adds a supplemental fastener kit and optional fasteners, clarifies 
certain procedures, and adds additional references.
    The FAA has determined that the inspection and follow-on corrective 
actions required by paragraph (a) of the final rule may be accomplished 
in accordance with either of those service bulletins. The final rule 
has been revised accordingly.

Editorial Changes to the Final Rule

    The FAA has determined that it is necessary to clarify what 
prompted this amendment in the Summary section of the AD by adding a 
more detailed description of the damage that occurred. The text now 
reads that a piece of the left wing inboard foreflap came off during a 
landing approach ``and struck and penetrated the airplane fuselage.'' 
The final rule has been changed accordingly.
    The FAA also has determined that it is necessary to clarify the 
intent of the final rule by specifying the types of discrepancies 
(missing, loose, or migrated shim; and loose fasteners) to be 
identified during the inspection required by paragraph (a) of this AD. 
Paragraph (a) and the Summary section of the final rule has been 
revised accordingly.
    The FAA also has determined that it is necessary to further clarify 
paragraph (a) of this AD. The FAA has added that follow-on corrective 
actions are required ``if any discrepancy is detected,'' and that the 
corrective actions are to be accomplished in accordance with the 
applicable chapter of the Boeing Airplane Maintenance Manual specified 
in either the previously referenced alert service bulletin or Revision 
1. Paragraph (a) of this AD has been revised accordingly.

[[Page 9908]]

Conclusion

    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 changes previously 
described. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Cost Impact

    There are approximately 991 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 213 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 1 work 
hour per airplane to accomplish the required inspection, and that the 
average labor rate is $60 per work hour. Based on these figures, the 
cost impact of the AD on U.S. operators is estimated to be $12,780, or 
$60 per airplane.
    The 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.

Regulatory Impact

    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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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

99-05-02 Boeing: Amendment 39-11051. Docket 97-NM-254-AD.

    Applicability: Model 747-100, 747-200B, 747-200F, 747-200C, 
747SR, 747-100B, 747-300, 747-100B SUD, 747-400, 747-400D, and 747-
400F series airplanes; having line numbers 1 through 1,116 
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 request approval for an 
alternative method of compliance in accordance with paragraph (b) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the failure of the outboard sequence carriage 
fitting, which could allow the wing inboard foreflap to separate and 
penetrate the fuselage, possibly injuring passengers and 
crewmembers, accomplish the following:
    (a) Within 1,500 landings or 18 months after the effective date 
of this AD, whichever occurs first, perform a one-time detailed 
visual inspection of the outboard sequence carriage attachment 
fitting to detect any discrepancy (missing, loose, or migrated shim; 
and loose fasteners) in accordance with Boeing Alert Service 
Bulletin 747-57A2302, dated April 10, 1997, or Boeing Service 
Bulletin 747-57A2302, Revision 1, dated June 18, 1998. If any 
discrepancy is detected, accomplish follow-on corrective actions in 
accordance with the applicable chapter of the Boeing Airplane 
Maintenance Manual specified in either of the service bulletins.
    (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 2: 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 actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-57A2302, dated April 10, 1997, or Boeing 
Service Bulletin 747-57A2302, Revision 1, dated June 18, 1998. 
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 April 5, 1999.

    Issued in Renton, Washington, on February 18, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-4630 Filed 2-26-99; 8:45 am]
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