[Federal Register Volume 63, Number 197 (Tuesday, October 13, 1998)]
[Rules and Regulations]
[Pages 54569-54570]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26966]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-185-AD; Amendment 39-10826; AD 98-21-17]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes 
Equipped with Pratt & Whitney Model JT9D-70 Engines

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 series airplanes, that 
currently requires repetitive inspections to detect fatigue cracking of 
the spring beams on the outboard struts; replacement of cracked spring 
beams with new or serviceable spring beams; and follow-on actions. That 
action also provides an optional terminating action for the repetitive 
inspections. This amendment removes that optional terminating action, 
and requires a new terminating action. This amendment is prompted by 
the development of an improved process for manufacturing titanium 
spring beams that will eliminate the embedded porosity flaws in the 
existing spring beams from which fatigue cracking can originate. The 
actions specified by this AD are intended to prevent fatigue cracking 
of the spring beam, which could result in loss of an outboard strut.

DATES: Effective November 17, 1998.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2171, Revision 1, dated June 27, 1996; and Boeing Service 
Bulletin 747-54-2177, dated June 27, 1996; as listed in the 
regulations; is approved by the Director of the Federal Register as of 
November 17, 1998.
    The incorporation by reference of Boeing Alert Service Bulletin 
747-54A2171, dated October 31, 1994, was approved previously by the 
Director of the Federal Register as of December 22, 1994 (59 FR 63003, 
December 7, 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: 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) by superseding AD 94-25-01, 
amendment 39-9085 (59 FR 63003, December 7, 1994), which is applicable 
to certain Boeing Model 747 series airplanes, was published in the 
Federal Register on July 7, 1998 (63 FR 36628). The action continues to 
require repetitive inspections to detect fatigue cracking of the spring 
beams on the outboard struts; replacement of cracked spring beams with 
new or serviceable spring beams; and follow-on actions. The action also 
proposed to remove the previously optional terminating action, and 
require a new terminating action.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the single comment received.
    The commenter supports the proposed rule.

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 as proposed.

Cost Impact

    There are approximately 7 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 5 airplanes of U.S. registry 
will be affected by this AD.
    The inspections that are currently required by AD 94-25-01, and 
retained in this AD, take approximately 40 work hours per airplane, per 
inspection cycle, to accomplish, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the currently 
required inspections on U.S. operators is estimated to be $12,000, or 
$2,400 per airplane, per inspection cycle.
    The new replacement required by this AD will take approximately 376 
work hours per airplane to accomplish, at an average labor rate of $60 
per work hour. Required parts will cost approximately $105,000 per 
airplane. Based on these figures, the cost impact of the replacement 
required by this AD on U.S. operators is estimated to be $637,800, or 
$127,560 per airplane.
    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.

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.

[[Page 54570]]

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-9085 (59 FR 
63003, December 7, 1994), and by adding a new airworthiness directive 
(AD), amendment 39-10826, to read as follows:

98-21-17  Boeing: Amendment 39-10826. Docket 97-NM-185-AD. 
Supersedes AD 94-25-01, Amendment 39-9085.

    Applicability: Model 747 series airplanes, line numbers 202 
through 396 inclusive, equipped with Pratt & Whitney Model JT9D-70 
engines; 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 (f) 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 fatigue cracking of the spring beam, which could 
result in loss of an outboard strut, accomplish the following:
    (a) Prior to the accumulation of 10,000 total flight cycles, or 
within 30 days after December 22, 1994 (the effective date of AD 94-
25-01), whichever occurs later, perform a detailed visual inspection 
to detect fatigue cracking of the spring beams on the outboard 
struts, in accordance with Boeing Alert Service Bulletin 747-
54A2171, dated October 31, 1994, or Revision 1, dated June 27, 1996. 
(Remove the gap covers and fairing access panels to perform this 
inspection.)
    (1) If no cracking is detected, repeat the visual inspection 
thereafter at intervals not to exceed 300 flight cycles until the 
requirements of paragraph (d) of this AD have been accomplished.
    (2) If any cracking is detected, prior to further flight, 
accomplish the replacement actions specified in paragraph (d) of 
this AD.

    Note 2: Accomplishment of the optional terminating action 
specified in paragraph (b) of AD 94-25-01 does not constitute 
terminating action for the requirements of this AD.

    (b) For airplanes that have accomplished terminating action in 
accordance with paragraph (b) of AD 94-25-01: Within 1,000 flight 
cycles after accomplishment of the terminating action specified by 
AD 94-25-01, or within 90 days after the effective date of this AD, 
whichever occurs later, perform a detailed visual inspection to 
detect fatigue cracking of the spring beams on the outboard struts, 
in accordance with Boeing Alert Service Bulletin 747-54A2171, dated 
October 31, 1994, or Revision 1, dated June 27, 1996.
    (1) If no cracking is detected, repeat the detailed visual 
inspection thereafter at intervals not to exceed 300 flight cycles 
until the requirements of paragraph (d) of this AD have been 
accomplished.
    (2) If any cracking is detected, prior to further flight, 
accomplish the replacement actions specified in paragraph (d) of 
this AD.
    (c) For airplanes that have accomplished installation of the 
Boeing-inspected spare titanium spring beams in accordance with 
Boeing Service Bulletin 747-54A2171, Revision 1, dated June 27, 
1996: Within 3,000 flight cycles after accomplishment of the 
installation of the spare spring beams, or within 90 days after the 
effective date of this AD, whichever occurs later, perform a 
detailed visual inspection to detect fatigue cracking of the spring 
beams on the outboard struts, in accordance with Boeing Alert 
Service Bulletin 747-54A2171, dated October 31, 1994, or Revision 1, 
dated June 27, 1996.
    (1) If no cracking is detected, repeat the detailed visual 
inspection thereafter at intervals not to exceed 300 flight cycles 
until the requirements of paragraph (d) of this AD have been 
accomplished.
    (2) If any cracking is detected, prior to further flight, 
accomplish the replacement actions specified in paragraph (d) of 
this AD.
    (d) For all airplanes: Prior to the accumulation of 10,000 total 
flight cycles, or within 18 months after the effective date of this 
AD, whichever occurs later, replace the spring beams on the outboard 
struts with new, improved spring beams, in accordance with Boeing 
Service Bulletin 747-54-2177, dated June 27, 1996. Accomplishment of 
this replacement constitutes terminating action for the repetitive 
inspection requirements of this AD.
    (e) As of the effective date of this AD, no person shall install 
a spring beam assembly, part numbers 65B89175-5, -6, -9, -10, -13, -
14, -19, and -20, on any airplane.
    (f) 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (g) 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.
    (h) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-54A2171, dated October 31, 1994, or Boeing 
Alert Service Bulletin 747-54A2171, Revision 1, dated June 27, 1996; 
and Boeing Service Bulletin 747-54-2177, dated June 27, 1996.
    (1) The incorporation by reference of Boeing Alert Service 
Bulletin 747-54A2171, Revision 1, dated June 27, 1996, and Boeing 
Service Bulletin 747-54-2177, dated June 27, 1996, 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 747-54A2171, dated October 31, 1994, was approved 
previously by the Director of the Federal Register as of December 
22, 1994 (59 FR 63003, December 7, 1994).
    (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.
    (i) This amendment becomes effective on Novmeber 17, 1998.

    Issued in Renton, Washington, on October 1, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-26966 Filed 10-9-98; 8:45 am]
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