AD 2000-25-12

[Federal Register Volume 65, Number 248 (Tuesday, December 26, 2000)]
[Rules and Regulations]
[Pages 81331-81333]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-32407]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NM-134-AD; Amendment 39-12047; AD 2000-25-12]
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 
inspections to detect cracking of the front spar web of the wing, and 
corrective action, if necessary. The actions specified by this AD are 
necessary to detect and correct fatigue cracking of the front spar web, 
which could result in fuel leaking onto an engine and a consequent 
fire. This action is intended to address the identified unsafe 
condition.

DATES: Effective January 30, 2001.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 30, 2001.

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: Tamara Anderson, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, 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 July 31, 2000 (65 FR 
46672). That action proposed to require inspections to detect cracking 
of the front spar web of the wing, and corrective action, if necessary.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Provide for Airplanes With Replaced Front Spar Web

    One commenter states that the airplane manufacturer informed it 
that inspections by Boeing Alert Service Bulletin 747-57A2311, dated 
January 27, 2000, are not necessary at this time for airplanes modified 
by Boeing Service Bulletin 747-57A2303. (In a separate comment, 
addressed below, the airplane manufacturer notes that the original 
issue of Boeing Alert Service Bulletin 747-57A2311 will be revised to, 
among other things, extend the compliance threshold for inspection of 
certain airplanes modified by Boeing Service Bulletin 747-57A2303.)
    The commenter makes no specific request for a change to the 
proposed rule. The FAA infers that the commenter is requesting that the 
FAA revise the proposed rule to extend the compliance time for the 
inspections required by paragraph (a) of this AD for airplanes that 
have been modified by Boeing Service Bulletin 747-57A2303, Revision 1, 
dated September 25, 1997. The FAA concurs with this request. The 
modification to which the commenter refers involves replacement of the 
front spar web of the wing with a new shot-peened front spar web, and 
it is provided as an optional terminating action in paragraph (c) of AD 
99-10-09, amendment 39-11162 (64 FR 25194, May 11, 1999). The FAA finds 
that, if this optional terminating action has been done, operators are 
not required to inspect the new section of the front spar web that 
overlaps with the inspection area specified in this AD (the area 
between FSSI 668 and FSSI 684) until 13,000 flight cycles or 30,000 
flight hours after the accomplishment of the replacement. A new 
paragraph (b) has been added to this AD to specify this, and subsequent 
paragraphs have been reordered accordingly.

Request To Specify Method of Compliance for Modified Airplanes

    One commenter requests that the FAA revise the proposed rule to 
provide special inspection instructions for airplanes modified in 
accordance with Boeing Service Bulletin 747-57A2303. The commenter 
points out that if the modification in that service bulletin is 
installed, it is not possible to accomplish the ``Part 2 optional web 
inspection'' given as one option for

[[Page 81332]]

compliance with paragraph (a) of the proposed AD, due to the proximity 
of a new web splice on the aft face of the front spar web. Thus, 
airplanes modified per Boeing Service Bulletin 747-57A2303 can only be 
inspected using the ``Part 1 external web inspection'' in paragraph (a) 
of this AD.
    The FAA partially concurs with the commenter's request. The FAA 
does not find it necessary to revise this AD to include special 
instructions for airplanes modified with another AD. Operators should 
note that most AD actions address modifications affecting the subject 
area of the AD using the note that appears as Note 1 of this AD, which 
states, ``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 (d) of this AD.'' However, to 
be clear, the FAA finds that it is appropriate in this case to clarify 
that operators of airplanes modified by Boeing Service Bulletin 747-
57A2303, Revision 1, must apply for an alternative method of 
compliance, in accordance with paragraph (d) of this AD, if they choose 
to comply with this AD using the Part 2 optional web inspection. Note 3 
has been added to this AD accordingly.

Request to Delay Issuance of Final Rule

    One commenter, the airplane manufacturer, requests that the FAA 
delay issuance of the proposed AD until a new revision of Boeing Alert 
Service Bulletin 747-57A2311 is issued. The commenter describes several 
changes that will be made to this service bulletin, which is referenced 
as the appropriate source of service information in the proposed rule. 
These changes include:
    <bullet> For certain airplanes modified by Boeing Service Bulletin 
747-57A2303, the compliance threshold for inspecting certain areas will 
be extended. (See ``Request to Provide for Airplanes With Replaced 
Front Spar Web,'' above.)
    <bullet> The type of inspection will be revised for certain 
airplanes on which web splice plates have been installed by Boeing 
Service Bulletin 747-57A2303. (See ``Request to Specify Method of 
Compliance for Modified Airplanes,'' above.)
    <bullet> The inspection area will be expanded.
    <bullet> Instructions for terminating action and post-modification 
inspections will be included.
    The FAA does not concur with the commenter's request to delay the 
issuance of this final rule. The FAA finds that, in view of the 
criticality of the unsafe condition addressed in this AD, it would be 
inappropriate to delay issuance of this AD pending receipt of a new 
service bulletin. Once the new service bulletin has been approved, the 
FAA may consider further rulemaking to mandate the actions in that 
bulletin. However, note that, based on the requests of another 
commenter, changes have been made to this AD related to the first two 
items listed by the commenter. See ``Request to Provide for Airplanes 
With Replaced Front Spar Web'' and ``Request to Specify Method of 
Compliance for Modified Airplanes,'' above, for more information on 
these changes.

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 478 Model 747 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 97 
airplanes of U.S. registry will be affected by this AD.
    The external inspections that are one option for compliance with 
this AD will take approximately 48 work hours per airplane (not 
including access and close-up), at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the external 
inspections on U.S. operators is estimated to be $2,880 per airplane, 
per inspection cycle.
    In lieu of accomplishment of the external inspections, this AD 
provides an optional web inspection that takes approximately 50 work 
hours per airplane, at an average labor rate of $60 per work hour. 
Based on these figures, the cost impact of the optional web inspection 
on U.S. operators is estimated to be $3,000 per airplane, per 
inspection cycle.
    The cost impact figures discussed above are 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 cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

Regulatory Impact

    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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:

2000-25-12  Boeing: Amendment 39-12047. Docket 2000-NM-134-AD.

    Applicability: Model 747 series airplanes, as listed in Boeing 
Alert Service Bulletin 747-57A2311, dated January 27, 2000; 
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

[[Page 81333]]

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 (d) 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 detect and correct fatigue cracking of the front spar web of 
the wing, which could result in fuel leaking onto an engine and a 
consequent fire, accomplish the following:

Repetitive Inspections

    (a) At the later of the times specified in paragraphs (a)(1) and 
(a)(2) of this AD, except as provided by paragraph (b) of this AD, 
perform the Part 1 external web inspection--including detailed 
visual, ultrasonic, and high frequency eddy current (HFEC) 
inspections--to detect cracking of the front spar web of the wing, 
in accordance with Boeing Alert Service Bulletin 747-57A2311, dated 
January 27, 2000. In lieu of the Part 1 external web inspection, 
accomplishment of the Part 2 optional web inspection to detect 
cracking--which also includes detailed visual, ultrasonic, and HFEC 
inspections--in accordance with Boeing Alert Service Bulletin 747-
57A2311, dated January 27, 2000, is acceptable for compliance with 
this paragraph. Repeat the inspections thereafter at intervals not 
to exceed 2,000 flight cycles.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (1) Prior to the accumulation of 13,000 total flight cycles or 
30,000 total flight hours, whichever occurs first.
    (2) Within 18 months after the effective date of this AD.

    Note 3: Operators of airplanes modified by Boeing Service 
Bulletin 747-57A2303, Revision 1, dated September 25, 1997; as 
allowed by paragraph (c) of AD 99-10-09, amendment 39-11162; must 
apply for an alternative method of compliance, in accordance with 
paragraph (d) of this AD, if they choose to use the Part 2 optional 
web inspection to comply with paragraph (a) of this AD.

Exception for Modified Airplanes

    (b) For airplanes on which the front spar web between front spar 
station inboard (FSSI) 668 and FSSI 692 has been replaced with a 
shot-peened front spar web in accordance with AD 99-10-09, amendment 
39-11162: Within 13,000 flight cycles or 30,000 flight hours after 
the replacement, whichever occurs first, inspect the new section of 
the front spar web that overlaps with the inspection area specified 
in Boeing Alert Service Bulletin 747-57A2311 (the area between front 
spar station inboard (FSSI) 668 and FSSI 684), dated January 27, 
2000, and repeat the inspections thereafter, in accordance with 
paragraph (a) of this AD.

Repair

    (c) If any cracking is detected during any inspection required 
by paragraph (a) or (b) of this AD, prior to further flight, repair 
in accordance with a method approved by the Manager, Seattle 
Aircraft Certification Office (ACO), FAA; or in accordance with data 
meeting the type certification basis of the airplane approved by a 
Boeing Company Designated Engineering Representative who has been 
authorized by the Manager, Seattle ACO, to make such findings. For a 
repair method to be approved by the Manager, Seattle ACO, as 
required by this paragraph, the approval letter must specifically 
reference this AD.

Alternative Methods of Compliance

    (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 ACO. 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 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

Special Flight Permits

    (e) Special flight permits may be issued in accordance with 
Secs. 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.

Incorporation by Reference

    (f) Except as provided by paragraph (c) of this AD, the actions 
shall be done in accordance with Boeing Alert Service Bulletin 747-
57A2311, dated January 27, 2000. 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.

Effective Date

    (g) This amendment becomes effective on January 30, 2001.

    Issued in Renton, Washington, on December 14, 2000.
Dorenda D. Baker,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-32407 Filed 12-22-00; 8:45 am]
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