AD Amdt-39-11431

[Federal Register Volume 64, Number 227 (Friday, November 26, 1999)]
[Rules and Regulations]
[Pages 66370-66372]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 99-30518]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-125-AD; Amendment 39-11431; AD 99-24-07]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 757 Series Airplanes 
Equipped With Rolls Royce Engines

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 757 series airplanes equipped with 
Rolls Royce RB211 engines, that requires modification of the nacelle 
strut and wing structure. This amendment is prompted by reports 
indicating that the actual operational loads applied to the nacelle are 
higher than the analytical loads that were used during the initial 
design. Such an increase in loading can lead to fatigue cracking in 
primary strut structure prior to an airplane's reaching its design 
service objective. The actions specified by this AD are intended to 
prevent fatigue cracking in primary strut structure and consequent 
reduced structural integrity of the strut.

DATES: Effective January 3, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 3, 2000.

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.


[[Page 66371]]


FOR FURTHER INFORMATION CONTACT: Rick Kawaguchi, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Transport Airplane Directorate, Seattle 
Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, 
Washington 98055-4056; telephone (425) 227-1153; 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 757 series 
airplanes was published in the Federal Register on August 20, 1999 (64 
FR 45483). That action proposed to require modification of the nacelle 
strut and wing structure of certain Boeing Model 757 series airplanes 
equipped with Rolls Royce RB211 engines.

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 indicates that it is not affected by the proposed 
rule.
    One commenter states that it plans to accomplish the requirements 
of 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 394 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 176 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 1,049 work 
hours per airplane to accomplish the required modification, and that 
the average labor rate is $60 per work hour. This work hour figure 
includes the time it will take to remove and reinstall the struts from 
the airplane as well as the time to gain and close access to the 
adjacent wing structure. Based on these figures, the cost impact of the 
modification required by this AD on U.S. operators is estimated to be 
$11,077,440, or $62,940 per airplane.
    This cost impact figure does not reflect the cost of the 
terminating actions described in the service bulletins listed in 
paragraph I.C., Table I, ``Strut Improvement Bulletins,'' on page 6 of 
Boeing Service Bulletin 757-54-0035, that are required to be 
accomplished prior to, or concurrently with, the modification of the 
nacelle strut and wing structure. Since some operators may have 
accomplished certain modifications on some or all of the airplanes in 
its fleet, while other operators may not have accomplished any of the 
modifications on any of the airplanes in its fleet, the FAA is unable 
to provide a reasonable estimate of the cost of accomplishing the 
terminating actions described in the service bulletins listed in Table 
I of the service bulletin.
    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. However, the FAA has been advised 
that manufacturer warranty remedies are available for part costs 
associated with accomplishing the actions required by this proposed AD. 
Therefore, the future economic cost impact of this rule on U.S. 
operators may be less than the cost impact figure indicated above.

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:

99-24-07 Boeing: Amendment 39-11431. Docket 99-NM-125-AD.

    Applicability: Model 757 series airplanes equipped with Rolls 
Royce engines, line numbers 1 through 735 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 fatigue cracking in primary strut structure and 
consequent reduced structural integrity of the strut, accomplish the 
following:
    (a) Modify the nacelle strut and wing structure in accordance 
with Boeing Service Bulletin 757-54-0035, dated July 17, 1997, at 
the later of the times specified in paragraph (a)(1) or (a)(2). All 
of the terminating actions described in the service bulletins listed 
in paragraph I.C., Table I, ``Strut Improvement Bulletins,'' on page 
6 of Boeing Service Bulletin 757-54-0035, must be accomplished in 
accordance with those service bulletins prior to, or concurrently 
with, the accomplishment of the modification of the nacelle strut 
and wing structure required by this paragraph.
    (1) Prior to the accumulation of 37,500 total flight cycles, or 
prior to 20 years since the date of manufacture of the airplane, 
whichever occurs first.
    (2) Within 3,000 flight cycles after the effective date of this 
AD.

Alternative Methods of Compliance

    (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.


[[Page 66372]]


    Note 2: 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

    (c) 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

    (d) The modification shall be done in accordance with Boeing 
Service Bulletin 757-54-0035, dated July 17, 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.
    (e) This amendment becomes effective on January 3, 2000.

    Issued in Renton, Washington, on November 17, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-30518 Filed 11-24-99; 8:45 am]
BILLING CODE 4910-13-P