[Federal Register Volume 64, Number 90 (Tuesday, May 11, 1999)]
[Rules and Regulations]
[Pages 25194-25197]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-11618]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-100-AD; Amendment 39-11162; AD 99-10-09]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-200, and 747-
SP Series Airplanes and Military Type E-4B Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain Boeing Model 747-100, -200, and 747-SP series 
airplanes and military type E-4B airplanes, that requires repetitive 
inspections to detect cracking of the wing front spar web, and repair 
of cracked structure. This amendment also provides for optional 
terminating action for the repetitive inspection requirements. This 
amendment is prompted by reports indicating that fatigue cracks were 
found on the aft surface of the wing front spar web. The actions 
specified by this AD are intended to detect and correct such fatigue 
cracking, which could result in a fuel leak, and consequent increased 
risk of a fire.

DATES: Effective June 15, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 15, 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 
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

[[Page 25195]]

Model 747-100, -200, and 747-SP series airplanes and military type E-4B 
airplanes was published in the Federal Register on May 28, 1998 (63 FR 
29151). That action proposed to require repetitive inspections to 
detect cracking of the wing front spar web, and repair of cracked 
structure. That proposal also provided for optional terminating action 
for the repetitive inspection requirements.

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.
    One commenter supports the proposed rule, and one commenter has no 
objection to the proposed rule.

Request to Allow Use of Additional Service Information

    Two commenters request that the proposed rule be revised to allow 
inspection and modification of the wing front spar web to be 
accomplished in accordance with the original issue of Boeing Alert 
Service Bulletin 747-57A2303, dated December 19, 1996. The notice of 
proposed rulemaking (NPRM) proposed to require inspection and 
modification of the wing front spar web in accordance with only Boeing 
Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997. The 
commenters point out that Boeing Service Bulletin 747-57A2303, Revision 
1, states that no more work is necessary for airplanes inspected or 
modified in accordance with the original issue of the service bulletin. 
One of the commenters states that revising the final rule to allow 
inspection and modification of the wing front spar web in accordance 
with the original issue of the service bulletin would preclude the need 
for affected operators to obtain approval for an alternative method of 
compliance.
    The FAA concurs with the commenters' request to allow inspection 
and modification of the wing front spar web in accordance with the 
original issue of Boeing Alert Service Bulletin 747-57A2303. The FAA 
has reviewed the original issue of the service bulletin and determined 
that the procedures in the original issue are substantially similar to 
those described in Revision 1. Therefore, ``NOTE 2'' has been added to 
this final rule to specify that inspections and modifications 
accomplished prior to the effective date of this AD in accordance with 
the original issue of Boeing Alert Service Bulletin 747-57A2303 are 
considered acceptable for compliance with this AD.

Request to Terminate Repetitive Inspections Required by AD 95-02-15

    One commenter requests that the proposal (Docket number 97-NM-100-
AD) be revised to state that, if the terminating action proposed in the 
NPRM (replacement of the wing front spar web with a new shot-peened 
wing front spar web) is accomplished, certain inspections outboard of 
front spar station inboard (FSSI) 669 that are currently required by AD 
95-02-15, amendment 39-9134 (60 FR 9613, March 21, 1995), are no longer 
necessary. The commenter points out that the subject area in the 
proposal overlaps considerably with the subject area of AD 95-02-15. 
The commenter also states that a similar revision should be made to the 
NPRM for docket number 97-NM-82-AD, which proposed the supersedure of 
AD 95-02-15, to state that certain inspections outboard of FSSI 669 are 
no longer necessary if the replacement of the wing front spar web with 
a new shot-peened wing front spar web is accomplished in accordance 
with this AD. The commenter states that addressing the area of overlap 
in the final rule would preclude the need for affected operators to 
obtain FAA approval for an alternative method of compliance for the 
inspections of the subject area of AD 95-02-15.
    The FAA partially concurs with the commenter's request to revise 
the NPRM's for docket numbers 97-NM-82-AD and 97-NM-100-AD. On July 15, 
1998, the FAA issued AD 98-15-21, amendment 39-10672 (63 FR 39487, 
dated July 23, 1998), which supersedes AD 95-02-15. Because that AD has 
already been issued, no revision to that final rule will be made at 
this time. However, the FAA concurs that accomplishment of the optional 
terminating action specified in this final rule would eliminate the 
need for inspections in accordance with AD 98-15-21 for the modified 
area only (i.e., FSSI 669 to FSSI 697 inclusive). Therefore, paragraph 
(c) of this final rule has been revised to state that replacement of 
the affected wing front spar web with a new shot-peened wing front spar 
web in accordance with Boeing Service Bulletin 747-57A2303, Revision 1, 
constitutes terminating action for repetitive inspections in accordance 
with AD 98-15-21 for the modified area only. In addition, ``NOTE 3'' 
has been added to this final rule to clarify that the area subject to 
the optional terminating action specified in paragraph (c) of this 
final rule overlaps with part of the wing front spar that is the 
subject of AD 98-15-21.

Request to Approve Alternative Method of Compliance for Terminating 
Action

    One commenter requests that the proposed rule be revised to allow 
modifications of the wing front spar web accomplished previously in 
accordance with Boeing Service Letter 747-SL-57-084-C, dated October 
12, 1996, and Boeing Repair Drawing 112U8040, to be considered 
terminating action for the requirements of this AD. The commenter 
states that such a modification was coordinated through the 
manufacturer, and the commenter has accomplished the modification on 
several of its airplanes.
    The FAA does not concur with the commenter's request to approve an 
alternative method of compliance for the terminating action. The 
service letter and repair drawing referenced by the commenter are not 
approved by the FAA. Therefore, the FAA finds that modifications 
accomplished in accordance with these data may not be adequate to 
ensure that the unsafe condition is adequately addressed. In addition, 
the FAA finds that adding such an alternative method of compliance for 
the terminating action to the final rule would unduly complicate this 
AD action and may be confusing to some operators. However, the operator 
may request approval of an alternative method of compliance in 
accordance with paragraph (d) of the final rule. No change to the final 
rule is necessary in this regard.

Explanation of Changes Made to the Proposal

    The FAA has revised paragraph (b)(2) of the final rule to add a 
provision that allows repair of any crack in the subject area to be 
accomplished 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 FAA to make 
such findings.

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 described 
previously. 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 190 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 95 airplanes of U.S. registry 
will be

[[Page 25196]]

affected by this AD, that it will take approximately 64 work hours per 
airplane to accomplish the required inspection, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
the inspection required by this AD on U.S. operators is estimated to be 
$364,800, or $3,840 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.
    Should an operator elect to accomplish the optional terminating 
modification, it would take approximately 518 work hours per airplane 
to accomplish the modification, at an average labor rate of $60 per 
work hour. Required parts would cost approximately $17,000 per 
airplane. Based on these figures, the cost impact of the optional 
terminating modification is estimated to be $48,080 per airplane.

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:

99-10-09 Boeing: Amendment 39-11162. Docket 97-NM-100-AD.
    Applicability: Model 747-100, 747-200, and 747-SP series 
airplanes and military type E-4B airplanes; as listed in Boeing 
Service Bulletin 747-57A2303, Revision 1, dated September 25, 1997; 
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.
    Note 2: Inspections and modifications accomplished prior to the 
effective date of this AD in accordance with Boeing Alert Service 
Bulletin 747-57A2303, dated December 19, 1996, are considered 
acceptable for compliance with the applicable action specified in 
this amendment.
    To detect and correct fatigue cracking of the wing front spar 
web, which could result in a fuel leak, and consequent increased 
risk of a fire, accomplish the following:

Initial and Repetitive Inspections

    (a) Perform an ultrasonic inspection to detect cracking of the 
wing front spar web at the fastener rows behind and between the 
upper link fittings for the number 2 and 3 engine struts, in 
accordance with the Accomplishment Instructions of Boeing Service 
Bulletin 747-57A2303, Revision 1, dated September 25, 1997, at the 
time specified in paragraph (a)(1) or (a)(2) of this AD, as 
applicable.
    (1) For airplanes identified as Group 1, 2, 3, or 5 in the alert 
service bulletin: Inspect prior to the accumulation of 12,500 total 
flight cycles, or within 15 months after the effective date of this 
AD, whichever occurs later. Repeat the inspection thereafter at 
intervals not to exceed 2,200 flight cycles.
    (2) For airplanes identified as Group 4, 6, 7, 8, 9, or 10 in 
the alert service bulletin: Inspect prior to the accumulation of 
18,000 total flight cycles, or within 15 months after the effective 
date of this AD, whichever occurs later. Repeat the inspection 
thereafter at intervals not to exceed 3,000 flight cycles.

Corrective Actions

    (b) If any crack is found during any inspection required by 
paragraph (a) of this AD, prior to further flight, accomplish either 
paragraph (b)(1) or (b)(2) of this AD.
    (1) Accomplish the terminating action in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 747-57A2303, 
Revision 1, dated September 25, 1997. Accomplishment of this action 
constitutes terminating action for the repetitive inspection 
requirements of this AD; or
    (2) 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 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 Manager's approval letter must specifically reference 
this AD.

Optional Terminating Action

    (c) Replacement of the affected wing front spar web with a new 
shot-peened wing front spar web in accordance with the 
Accomplishment Instructions of Boeing Service Bulletin 747-57A2303, 
Revision 1, dated September 25, 1997, constitutes terminating action 
for the repetitive inspection requirements of this AD, and, for the 
modified area only, for the repetitive inspection requirements of AD 
98-15-21, amendment 39-10672.

    Note 3: The area subject to the optional terminating action 
specified in paragraph (c) of this AD overlaps with part of the wing 
front spar that is the subject of AD 98-15-21.

Alternative Method 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 
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) The inspections and replacement shall be done in accordance 
with Boeing Service Bulletin 747-57A2303, Revision 1, dated

[[Page 25197]]

September 25, 1997. 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 June 15, 1999.

    Issued in Renton, Washington, on May 3, 1999.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-11618 Filed 5-10-99; 8:45 am]
BILLING CODE 4910-13-P