[Federal Register Volume 65, Number 122 (Friday, June 23, 2000)]
[Rules and Regulations]
[Pages 39076-39077]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-15308]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-330-AD; Amendment 39-11797; AD 2000-12-19]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747 Series Airplanes

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 747 series airplanes, that requires 
repetitive inspections of the aft pressure bulkhead to detect cracking, 
and repair, if necessary. This amendment is prompted by a report of 
fatigue cracking found in the upper half of the aft pressure bulkhead. 
The actions specified by this AD are intended to detect and correct 
cracking in the aft pressure bulkhead, which could result in rapid 
decompression of the fuselage or overpressurization of the tail 
section.

DATES: Effective July 28, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 28, 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.

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 Model 747 series 
airplanes was published in the Federal Register on February 2, 2000 (65 
FR 4900). That action proposed to require repetitive inspections of the 
aft pressure bulkhead to detect cracking, and repair, if necessary.

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 comment 
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 552 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 84 airplanes of U.S. registry 
will be affected by this AD.
    It will take approximately 7 work hours per airplane to accomplish 
the required detailed visual inspection, at the average labor rate of 
$60 per work hour. Based on these figures, the cost impact of the 
required detailed visual inspection on U.S. operators is estimated to 
be $35,280, or $420 per airplane, per inspection cycle.
    It will take approximately 7 work hours per airplane to accomplish 
the required HFEC inspections, at the average labor rate of $60 per 
work hour. Based on these figures, the cost impact of the required HFEC 
inspections on U.S. operators is estimated to be $35,280, or $420 per 
airplane, per inspection cycle.
    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 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 adding the following new 
airworthiness directive:

2000-12-19  Boeing: Amendment 39-11797. Docket 99-NM-330-AD.

    Applicability: Model 747 series airplanes, as listed in Boeing 
Alert Service Bulletin 747-53A2425, dated October 29, 1998; 
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

[[Page 39077]]

accordance with paragraph (g) 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 cracking in the aft pressure bulkhead, 
which could result in rapid decompression of the fuselage or 
overpressurization of the tail section, accomplish the following:

Initial and Repetitive Inspections

    (a) Except as provided by paragraph (f) of this AD, prior to the 
accumulation of 20,000 total flight cycles, or within 12 months 
after the effective date of this AD, whichever occurs later, perform 
a detailed visual inspection of the upper half of the aft pressure 
bulkhead to detect cracking, in accordance with Figure 6 or 7, as 
applicable, of Boeing Alert Service Bulletin 747-53A2425, dated 
October 29, 1998. Repeat the detailed visual inspection thereafter 
at intervals not to exceed 1,500 flight cycles. For areas of the 
upper half of the aft pressure bulkhead that have been repaired 
previously, this detailed visual inspection may be deferred for up 
to 15,000 flight cycles after accomplishment of the repair, as 
described in the NOTE in paragraph 3.D. of the Accomplishment 
Instructions of the alert service bulletin.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

    (b) Except as provided by paragraph (f) of this AD, if no 
cracking is detected during the initial detailed visual inspection 
required by paragraph (a) of this AD: Within 1,500 flight cycles 
after accomplishment of that inspection, perform a high frequency 
eddy current (HFEC) inspection of the upper and lower halves of the 
aft pressure bulkhead to detect cracking, in accordance with Figure 
8 of Boeing Alert Service Bulletin 747-53A2425, dated October 29, 
1998. Repeat the HFEC inspection thereafter at intervals not to 
exceed 3,000 flight cycles.
    (c) Except as provided by paragraph (f) of this AD, if any 
cracking is detected during any inspection required by paragraph (a) 
of this AD: Prior to further flight, perform an HFEC inspection of 
the upper and lower halves of the aft pressure bulkhead to detect 
cracking, in accordance with Figure 8 or 9, as applicable, of Boeing 
Alert Service Bulletin 747-53A2425, dated October 29, 1998. Repeat 
the HFEC inspection thereafter at intervals not to exceed 3,000 
flight cycles.

Repair

    (d) Except as provided by paragraphs (e) and (f) of this AD, if 
any cracking is detected during any inspection required by paragraph 
(a), (b), or (c) of this AD: Prior to further flight, repair in 
accordance with Boeing Alert Service Bulletin 747-53A2425, dated 
October 29, 1998.
    (e) If any cracking is detected during any inspection required 
by paragraph (a), (b), or (c) of this AD, and Boeing Alert Service 
Bulletin 747-53A2425, dated October 29, 1998, specifies to contact 
Boeing for repair instructions: Repair any cracking, prior to 
further flight, 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 (DER) 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 approval letter must specifically reference this 
AD.

Operator's ``Equivalent Procedure''

    (f) Where Boeing Alert Service Bulletin 747-53A2425, dated 
October 29, 1998, specifies that an inspection or a repair, as 
applicable, may be accomplished in accordance with an operator's 
``equivalent procedure'': The inspection or repair, as applicable, 
must be accomplished in accordance with the applicable chapter of 
the Boeing 747 Maintenance Manual or the Boeing 747 Structural 
Repair Manual specified in the alert service bulletin.

Alternative Methods of Compliance

    (g) 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

    (h) 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

    (i) Except as provided by paragraphs (e) and (f) of this AD, the 
actions shall be done in accordance with Boeing Alert Service 
Bulletin 747-53A2425, dated October 29, 1998. 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.
    (j) This amendment becomes effective on July 28, 2000.

    Issued in Renton, Washington, on June 12, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-15308 Filed 6-22-00; 8:45 am]
BILLING CODE 4910-13-P