AD 2000-11-07

[Federal Register Volume 65, Number 106 (Thursday, June 1, 2000)]
[Rules and Regulations]
[Pages 34932-34935]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-13448]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-30-AD; Amendment 39-11755; AD 2000-11-07]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-200, -300, and -400 
Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain Boeing Model 747-200, -300, and -400 series 
airplanes, that currently requires repetitive high frequency eddy 
current (HFEC) inspections to detect cracking of the front spar web of 
the center section of the wing, and repair, if necessary. This 
amendment requires that the existing inspection be accomplished at a 
reduced threshold, and adds a requirement that the existing HFEC 
inspection be accomplished on repaired areas. This amendment is 
prompted by reports of cracking in repaired areas of the front spar web 
and cracking of the front spar web on an airplane that had accumulated 
fewer flight cycles than the inspection threshold of the existing AD. 
The actions specified by this AD are intended to prevent the leakage of 
fuel into the forward cargo bay, as a result of fatigue cracking in the 
front spar web, which could result in a potential fire hazard.

DATES: Effective July 6, 2000.
    The incorporation by reference of Boeing Service Bulletin 747-
57A2298, Revision 2, dated October 2, 1997, and Boeing Alert Service 
Bulletin 747-57A2298, Revision 3, dated January 7, 1999, as listed in 
the regulations, is approved by the Director of the Federal Register as 
of July 6, 2000.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-57A2298, Revision 1, dated September 12, 1996, as listed in the 
regulations, was approved previously by the Director of the Federal 
Register as of April 2, 1997 (62 FR 8613, February 26, 1997).

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; 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) by superseding AD 97-05-01, 
amendment 39-9945 (62 FR 8613, February 26, 1997), which is applicable 
to certain Boeing Model 747-200, -300, and -400 series airplanes, was 
published in the Federal Register on December 21, 1999 (64 FR 71336). 
The action proposed to require that the repetitive high frequency eddy 
current (HFEC) inspections to detect cracking of the front spar web of 
the center section of the wing required by the existing AD be 
accomplished at a reduced threshold. The action also proposed to 
require that

[[Page 34933]]

the HFEC inspection be accomplished on repaired areas.

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.

Support for the Proposal

    One commenter supports the proposed rule.

Request To Reference Additional Source of Service Information

    One commenter requests that the FAA revise paragraph (b) of the 
proposed rule to allow the HFEC inspection described in that paragraph 
to be accomplished in accordance with Boeing Alert Service Bulletin 
747-57A2298, Revision 1, dated September 12, 1996. [The proposed rule 
references Boeing Service Bulletin 747-57A2298, Revision 2, dated 
October 2, 1997, and Revision 3, dated January 7, 1999, as appropriate 
sources of service information for accomplishment of the actions 
required by paragraph (b).] The commenter states that the inspection 
method to detect cracking of the forward side of the front spar web in 
Revision 1 of the alert service bulletin is identical to the method 
described in Revisions 2 and 3. The commenter also states that 
operators who have accomplished the HFEC inspection in accordance with 
paragraph (a)(1) of AD 97-05-01 [which is restated as paragraph (a)(1) 
of this AD] should be given credit for performing the inspection. To 
this end, the commenter requests that the compliance time of paragraph 
(b) of this AD be revised from ``Prior to accumulation of 12,000 total 
landings, or within 12 months after the effective date of this AD, 
whichever occurs later,'' to incorporate an option for the inspection 
to be accomplished ``within 1,400 landings after the previous HFEC 
inspection.''
    The FAA partially concurs with the commenter's request. Although 
the inspection method is identical in Revisions 1, 2, and 3 of the 
service bulletin, as explained in the preamble of the proposed rule, 
Revisions 2 and 3 of the service bulletin describe an inspection of the 
aft side of the front spar web for areas where a repair is located on 
the forward side. For this reason, paragraph (b) of the proposed rule 
requires inspection in accordance with Revision 2 or 3 of the service 
bulletin. However, because the inspection is the same for airplanes 
without repairs in the area of the inspection, the FAA finds that 
inspections accomplished prior to the effective date of this AD in 
accordance with Revision 1 of the alert service bulletin are acceptable 
for compliance with the initial inspection required by paragraph (b) of 
this AD, provided that the airplane does not have a repair installed in 
the inspection area. A new ``Note 2'' has been added to this final rule 
accordingly. However, the FAA has determined that the accomplishment 
instructions in Revisions 2 and 3 of the service bulletin are clearer 
than those in Revision 1 of the alert service bulletin; therefore, 
inspections in accordance with paragraph (b) of this AD accomplished 
after the effective date of this AD are required to be accomplished in 
accordance with Revision 2 or 3 of the service bulletin.
    With regard to the commenter's request to revise the compliance 
time for the actions required by paragraph (b) of this AD, the FAA 
finds that no change to the final rule is required beyond the inclusion 
of the new ``Note 2,'' as described above. Credit is always given for 
actions accomplished prior to the effective date of an AD by means of 
the phrase, ``Compliance: Required as indicated, unless accomplished 
previously.''

Request To Revise Cost Impact Information

    One commenter requests that the FAA revise the estimated number of 
work hours stated in the cost impact section of the preamble of the 
proposed rule from 8 work hours to 48 work hours per airplane. The 
commenter points out that the manufacturer estimates 48 work hours per 
airplane in Boeing Alert Service Bulletin 747-57A2298, Revision 3, 
dated January 7, 1999. The commenter states that, based on its 
experience, the proposed actions take approximately 48 work hours.
    The FAA does not concur with the commenter's request. The estimate 
of 48 work hours given in the service bulletin includes time for 
gaining access and closing up. The cost analysis in AD rulemaking 
actions, however, typically does not include incidental costs, such as 
the time required to gain access and close up, planning time, or time 
necessitated by other administrative actions. Because incidental costs 
may vary significantly from operator to operator, they are almost 
impossible to calculate. The number of work hours necessary to 
accomplish the required actions, specified as 8 in the cost impact 
information in the proposal and restated below, represents the time 
necessary to perform only the actions actually required by this AD 
(that is, the inspection). No change to the final rule is necessary in 
this regard.

Request To Clarify ``Terminating Action'' Statement in Paragraph 
(b)

    One commenter, the airplane manufacturer, states that one operator 
was confused by the statement in paragraph (b) of the proposed rule 
that, ``Accomplishment of the HFEC inspection constitutes terminating 
action for the repetitive inspection requirements of paragraph (a) of 
this AD.'' The operator was confused because paragraph (a) of the 
proposed rule specifies repetitive inspections at intervals not to 
exceed 1,400 landings. The operator found these statements 
contradictory.
    The commenter makes no specific request for a change to the 
proposed rule. The FAA infers that the operator to whom the commenter 
refers does not understand the meaning of ``terminating action.'' 
Paragraph (a) of this AD states that the inspection in that paragraph 
is to be performed ``at the time specified in paragraph (a)(1) or 
(a)(2) of this AD, * * * until accomplishment of the requirements of 
paragraph (b) of this AD.'' As stated previously, paragraph (b) of this 
AD states that ``Accomplishment of the HFEC inspection constitutes 
terminating action for the repetitive inspection requirements of 
paragraph (a) of this AD.'' Once the initial inspection in accordance 
with paragraph (b) of this Ad has been accomplished, the repetitive 
inspections in paragraph (a) of this Ad are no longer necessary and 
need not be accomplished. The repetitive inspections specified in 
paragraph (b) of this AD must be accomplished at intervals not to 
exceed 1,400 landings (as stated in that paragraph). The FAA finds that 
no further clarification is necessary, and no change to the final rule 
is necessary in this regard.

Request To Revise AD Referencing Supplemental Structural Inspection 
Items

    One commenter requests that the FAA revise AD 94-15-18, amendment 
39-8989 (59 FR 41233, August 11, 1994), to exclude Supplemental 
Structural Inspection Document (SSID) Items W-3A and W-3B on SSID-
candidate airplanes that are included in the effectivity listing of 
Boeing Service Bulletin 747-57A2298. The commenter states that the SSID 
inspections allow detailed visual and surveillance inspections of the 
front spar web at ``D''-check intervals using sampling methods. This AD 
requires HFEC inspections of the front spar web at intervals not to 
exceed 1,400 landings

[[Page 34934]]

for all airplanes included in the applicability of this AD.
    The FAA does not concur with the commenter's request. The 
commenter's request is not relevant to this proposed rule. In the 
future, should the FAA consider further rulemaking to revise AD 94-15-
18, the issue raised by the commenter would be appropriate to address. 
No change to the final rule is necessary in this regard.

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 485 Model 747-200, -300, and -400 series 
airplanes of the affected design in the worldwide fleet. The FAA 
estimates that 105 airplanes of U.S. registry will be affected by this 
AD.
    The inspections that are currently required by AD 97-05-01 and 
retained in this AD, take approximately 8 work hours per airplane to 
accomplish, at an average labor rate of $60 per work hour. Based on 
these figures, the cost impact of the currently required actions on 
U.S. operators is estimated to be $50,400, or $480 per airplane, per 
inspection cycle.
    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 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 removing amendment 39-9945 (62 FR 
8613, February 26, 1997), and by adding a new airworthiness directive 
(AD), amendment 39-11755, to read as follows:

2000-11-07 Boeing: Amendment 39-11755. Docket 99-NM-30-AD. 
Supersedes AD 97-05-01, Amendment 39-9945.

    Applicability: Model 747-200, -300, and -400 series airplanes; 
up to and including line number 744; 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 (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 prevent the leakage of fuel into the forward cargo bay, as a 
result of fatigue cracking in the front spar web, which could result 
in a potential fire hazard, accomplish the following:

Restatement of Requirement of AD 97-05-01

Repetitive Inspections

    (a) Perform a high frequency eddy current (HFEC) inspection to 
detect cracking of the front spar web of the center section of the 
wing, in accordance with Boeing Alert Service Bulletin 747-57A2298, 
Revision 1, dated September 12, 1996; Boeing Service Bulletin 747-
57A2298, Revision 2, dated October 2, 1997; or Boeing Alert Service 
Bulletin 747-57A2298, Revision 3, dated January 7, 1999; at the time 
specified in paragraph (a)(1) or (a)(2) of this AD, as applicable, 
until accomplishment of the requirements of paragraph (b) of this 
AD.
    (1) For airplanes that have accumulated 12,000 to 17,999 total 
landings as of April 2, 1997 (the effective date of AD 97-05-01, 
amendment 39-9945): Perform the initial inspection within 12 months 
after April 2, 1997, unless previously accomplished within the last 
12 months prior to April 2, 1997. Perform this inspection again 
prior to the accumulation of 18,000 total landings or within 1,400 
landings, whichever occurs later; after accomplishing the initial 
inspection, and thereafter at intervals not to exceed 1,400 
landings.
    (2) For all other airplanes: Perform the initial inspection 
prior to the accumulation of 18,000 total landings or within 12 
months after April 2, 1997, whichever occurs later. Repeat this 
inspection thereafter at intervals not to exceed 1,400 landings.

New Requirements of This AD

Repetitive Inspections

    (b) Prior to accumulation of 12,000 total landings, or within 12 
months after the effective date of this AD, whichever occurs later, 
perform an HFEC inspection to detect cracking of the front spar web 
of the center section of the wing, in accordance with Boeing Service 
Bulletin 747-57A2298, Revision 2, dated October 2, 1997; or Boeing 
Alert Service Bulletin 747-57A2298, Revision 3, dated January 7, 
1999. Repeat the HFEC inspection thereafter at intervals not to 
exceed 1,400 landings. Accomplishment of the HFEC inspection 
constitutes terminating action for the repetitive inspection 
requirements of paragraph (a) of this AD.

    Note 2: Inspections accomplished prior to the effective date of 
this AD in accordance with Boeing Alert Service Bulletin 747-
57A2298, Revision 1, dated September 12, 1996, are acceptable for 
compliance with the initial inspection required by paragraph (b) of 
this AD, provided that the airplane does not have a repair installed 
in the inspection area.

Repair

    (c) If any cracking is detected during any inspection required 
by paragraph (a) or (b) of this AD, prior to further flight, confirm 
the cracking with secondary procedures in accordance with Boeing 
Service Bulletin 747-57A2298, Revision 2, dated October 2, 1997, or 
Boeing Alert Service Bulletin 747-57A2298, Revision 3, dated January 
7, 1999. Thereafter repeat the HFEC inspection required by paragraph 
(a) or (b) of this AD at intervals not to exceed 1,400 landings.
    (1) If any vertical crack is found that is less than 10 inches 
in length and has not extended in a diagonal direction, prior to 
further flight, repair in accordance with the service bulletin.
    (2) If any vertical crack is found that is 10 inches or greater 
in length; or if any crack is

[[Page 34935]]

found that has extended in a diagonal direction (regardless of the 
length); or if any crack is found that would affect an existing 
repair, prior to further flight, repair in accordance with a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA, Transport Airplane Directorate; or in accordance with 
data meeting the type certification basis of the airplane approved 
by a Boeing Designated Engineering Representative who has been 
authorized by the FAA 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 3: 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 
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.

Incorporation by Reference

    (f) Except as provided by paragraph (c)(2) of this AD, the 
actions shall be done in accordance with Boeing Alert Service 
Bulletin 747-57A2298, Revision 1, dated September 12, 1996; Boeing 
Service Bulletin 747-57A2298, Revision 2, dated October 2, 1997; or 
Boeing Alert Service Bulletin 747-57A2298, Revision 3, dated January 
7, 1999; as applicable. 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.
    (1) The incorporation by reference of Boeing Service Bulletin 
747-57A2298, Revision 2, dated October 2, 1997; and Boeing Alert 
Service Bulletin 747-57A2298, Revision 3, dated January 7, 1999; is 
approved by the Director of the Federal Register in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51.
    (2) The incorporation by reference of Boeing Alert Service 
Bulletin 747-57A2298, Revision 1, dated September 12, 1996; was 
approved previously by the Director of the Federal Register as of 
April 2, 1997 (62 FR 8613, February 26, 1997).
    (3) 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 July 6, 2000.

    Issued in Renton, Washington, on May 23, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-13448 Filed 5-31-00; 8:45 am]
BILLING CODE 4910-13-U