[Federal Register Volume 62, Number 248 (Monday, December 29, 1997)]
[Rules and Regulations]
[Pages 67550-67551]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-33668]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-294-AD; Amendment 39-10264; AD 97-26-21]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, 747-200, 747-300, 
747SR, and 747SP Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to certain Boeing Model 747-100, 747-200, 747-300, 747SR, 
and 747SP series airplanes. This action requires a one-time inspection 
to detect cracking of the longeron splice fittings at stringer 11, on 
the left and right sides at body station 2598, and replacement of any 
cracked fitting with a new fitting. This amendment is prompted by 
reports that fatigue cracking was found on longeron splice fittings. 
The actions specified in this AD are intended to detect and correct 
such fatigue cracking, which could result in reduced controllability of 
the horizontal stabilizer.

DATES: Effective January 13, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of January 13, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before February 27, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-294-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    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 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.

FOR FURTHER INFORMATION CONTACT: Bob Breneman, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington; telephone (425) 227-2776; 
fax (425) 227-1181.

SUPPLEMENTARY INFORMATION: The FAA has received three reports 
indicating that fatigue cracking was found on the longeron splice 
fittings at stringer 11 on Boeing Model 747SR and 747-200 series 
airplanes. The most recent cracking was detected on an airplane that 
had accumulated 62,783 total flight hours and 16,867 total flight 
cycles. Such fatigue cracking, if not detected and corrected in a 
timely manner, could result in reduced controllability of the 
horizontal stabilizer.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Boeing Alert Service Bulletin 
747-53A2410, Revision 2, dated October 30, 1997, including Addendum, 
which describes procedures for repetitive detailed inspections to 
detect cracking of the longeron splice fittings at stringer 11, on the 
left and right sides at body station 2598, and replacement of any 
cracked fitting with a new fitting. The alert service bulletin 
specifies various compliance times for groups of airplanes having 
different flight hour and flight cycle thresholds.

Explanation of the Requirements of the Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Boeing Model 747-100, 747-200, 747-300, 
747SR, and 747SP series airplanes of the same type design, this AD 
requires a one-time detailed inspection to detect cracking of the 
longeron splice fittings at stringer 11, on the left and right sides at 
body station 2598, and replacement of any cracked fitting with a new 
fitting. The actions are required to be accomplished in accordance with 
the alert service bulletin described previously.

Differences Between the AD and the Alert Service Bulletin

    The AD differs from the previously described alert service bulletin 
in that the AD requires a one-time inspection and shortened compliance 
time, rather than the repetitive inspections and multiple compliance 
times specified in the referenced alert service bulletin. The recent 
report of cracking detected on a Boeing Model 747-200 series airplane 
at a relatively low threshold has indicated the need for interim action 
requiring inspection at an early date, directed to those airplanes that 
have accumulated the highest number of flight hours or flight cycles 
(i.e., 78,000 total flight hours or 22,000 total flight cycles).
    In addition, the AD differs from the alert service bulletin by 
providing a compliance period in terms of calendar time, rather than 
flight cycles/hours, for those airplanes that have exceeded the 
threshold. Due to the limited availability of replacement fittings, a 
90-day compliance period is provided by this AD. This compliance period 
will allow the operators of affected airplanes an opportunity to 
schedule the inspection and have necessary replacement fittings 
available if cracks are found during the inspection.

Interim Action

    This AD is considered to be interim action. The FAA is considering 
separate rulemaking action that would propose similar inspections at 
repetitive intervals for all airplanes affected by the previously 
described alert service bulletin.

[[Page 67551]]

Determination of Rule's Effective Date

    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications shall identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-NM-294-AD.'' The postcard will be date stamped and 
returned to the commenter.

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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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:

97-26-21  Boeing: Amendment 39-10264. Docket 97-NM-294-AD.

    Applicability: Model 747-100, 747-200, 747-300, 747SR, and 747SP 
series airplanes having line positions 201 through 886 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 
otherwise 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 detect and correct fatigue cracking of the longeron splice 
fittings at stringer 11, which could result in reduced 
controllability of the horizontal stabilizer, accomplish the 
following:
    (a) Perform a one-time detailed visual inspection to detect 
cracking of the longeron fittings at stringer 11, on the left and 
right sides at body station 2598, at the later of the times 
specified in paragraphs (a)(1) and (a)(2) of this AD, in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin 747-53A2410, Revision 2, dated October 30, 1997, including 
Addendum. If any crack is detected, prior to further flight, replace 
the cracked fitting with a new fitting, in accordance with the alert 
service bulletin.
    (1) Inspect prior to the accumulation of 22,000 total flight 
cycles or 78,000 total flight hours, whichever occurs first; or
    (2) Inspect within 90 days after the effective date of this AD.

    Note 2: Where there are differences between the AD and the alert 
service bulletin, the AD prevails.

    (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.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Seattle ACO.

    (c) 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.
    (d) The actions shall be done in accordance with Boeing Alert 
Service Bulletin 747-53A2410, Revision 2, dated October 30, 1997, 
including Addendum. 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 13, 1998.

    Issued in Renton, Washington, on December 19, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-33668 Filed 12-24-97; 8:45 am]
BILLING CODE 4910-13-U