[Federal Register Volume 65, Number 21 (Tuesday, February 1, 2000)]
[Rules and Regulations]
[Pages 4757-4759]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-1765]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-282-AD; Amendment 39-11529; AD 2000-02-10]
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 to detect broken fasteners and cracking of the 
forward edge frame for main entry door number 3, and repair, if 
necessary. This amendment is prompted by reports of fatigue cracks at 
the inner chord and web of the body station 1265 edge frame between 
stringers 23 and 27. The actions specified by this AD are intended to 
detect and correct such cracking, which could result in rapid 
depressurization of the airplane.

DATES:  Effective March 7, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 7, 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) 227-2771.

[[Page 4758]]


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 August 20, 1999 (64 
FR 45466). That action proposed to require repetitive inspections to 
detect broken fasteners and cracking of the forward edge frame for main 
entry door number 3, and repair, if necessary.

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Request To Clarify Inspection Requirements for Group 2 Airplanes

    One commenter states that the proposed AD should clarify that 
previous accomplishment of the inspections required for Group 2 
airplanes, in accordance with Boeing Alert Service Bulletin 747-
53A2416, dated April 23, 1998, is adequate for meeting the inspection 
requirements of the proposed rule. (Group 2 airplanes are identified in 
Revision 1, dated May 6, 1999, of the alert service bulletin.) The 
commenter advises that all of its airplanes were included in the 
effectivity of the original release of the alert service bulletin and 
that the inspection requirements of the proposed AD, in accordance with 
the original release, have been accomplished. The commenter adds that 
no additional inspection requirements were added in Revision 1 of the 
alert service bulletin. For those reasons, the commenter requests 
changing the proposed AD to allow accomplishment of the flight safety 
inspections in accordance with the original release of the Boeing alert 
service bulletin instead of Revision 1 for Group 2 airplanes.
    The FAA does not concur that it is necessary to change the proposed 
AD to cite the original release of the alert service bulletin rather 
than Revision 1 with regard to the inspections required for Group 2 
airplanes. The FAA points out that the procedures in both of the alert 
service bulletins are identical for Group 2 airplanes. Therefore, the 
FAA agrees that inspections accomplished in accordance with the 
original release of the alert service bulletin meet the requirements of 
paragraph (a) of the proposed AD for Group 2 airplanes only. To clarify 
this, a note has been added to the final rule following paragraph (a).

Request To Clarify Certain Terminology in the Proposed Rule

    One commenter requests minor editorial changes and clarification of 
certain terminology used in the proposed AD, as follows:
     In the second sentence of the ``Explanation of Relevant 
Service Information,'' section and in Note 3 following paragraph (a) of 
the proposed AD, the commenter requests changing ``inspection of 
certain fasteners'' to ``inspection of certain fastener holes.'' 
Although the ``Explanation'' section is not included in the final rule, 
the FAA concurs that such a change adds clarity to the inspection 
requirements, and has changed this phrase accordingly in Note 4 of the 
final rule. (Note 3 of the proposed rule is renumbered as Note 4 in the 
final rule.)
     In the first sentence of paragraph (c) of the proposed AD, 
the commenter requests changing ``If any broken fastener or cracking'' 
to ``If any broken fasteners or cracking of structure.'' The FAA 
concurs with this request and has clarified this phrase accordingly in 
paragraphs (a), (b), and (c), and in Note 4, of the final rule.
     The commenter recommends that the heading preceding 
paragraph (c) of the proposed AD be called ``Repair'' or ``Correction'' 
rather than just ``Repair.'' The commenter contends that ``Correction'' 
should be added to the heading because the statement of the unsafe 
condition specified that the action required is to detect and 
``correct'' cracking. The FAA does not concur and considers that 
``Repair'' is adequate for describing the action required to address 
the unsafe condition. For that reason, no change to the final rule is 
necessary in this regard.

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 previously 
described. 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 1,182 Model 747 series airplanes of the 
affected design in the worldwide fleet. The FAA estimates that 251 
airplanes of U.S. registry will be affected by this AD.
    The FAA estimates that it will take approximately 1 work hour per 
airplane to accomplish the inspection of the frames at the floor 
intercostal, and that the average labor rate is $60 per work hour. 
Based on these figures, the cost impact of the AD on U.S. operators is 
estimated to be $15,060, or $60 per airplane, per inspection cycle.
    The FAA also estimates that the inspection of the frames at the top 
of the inner chord reinforcement strap is required to be accomplished 
on 103 U.S.-registered airplanes. It is estimated that it will take 
approximately 1 work hour per airplane to accomplish the inspection, 
and that the average labor rate is $60 per work hour. Based on these 
figures, the cost impact of the AD on U.S. operators is estimated to be 
$6,180, or $60 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:

[[Page 4759]]

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:

2000-02-10  Boeing:

    Amendment 39-11529. Docket 98-NM-282-AD.
    Applicability: Model 747 series airplanes, as listed in Boeing 
Alert Service Bulletin 747-53A2416, Revision 1, dated May 6, 1999; 
certificated in any category.

    Note 1:  This AD also applies to airplanes that have been 
converted from a passenger configuration to a special freighter 
configuration.


    Note 2:  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.

    To detect and correct cracking of the inner chord and web of the 
body station 1265 edge frame between stringers 23 and 27, which 
could result in rapid depressurization of the airplane, accomplish 
the following:

Inspections

    (a) Accomplish the flight safety inspections of the frames at 
the floor intercostal to detect any broken fasteners and cracking of 
structure, in accordance with Figure 5 of Boeing Alert Service 
Bulletin 747-53A2416, Revision 1, dated May 6, 1999, at the 
applicable time specified in paragraph (a)(1), (a)(2), or (a)(3) of 
this AD. Repeat the inspection thereafter at intervals not to exceed 
3,000 flight cycles.

    Note 3:  Accomplishment of the flight safety inspections of the 
frames at the floor intercostal on Group 2 airplanes prior to the 
effective date of this AD, in accordance with Boeing Alert Service 
Bulletin 747-53A2416, dated April 23, 1998, is considered acceptable 
for compliance with the actions required by paragraph (a) of this 
AD. However, Group 1 airplanes, as specified by paragraph (b) of 
this AD, that were inspected in accordance with the original release 
of the alert service bulletin are not exempt from the requirements 
of paragraph (b) of this AD.


    Note 4:  Figure 5 of the alert service bulletin includes a 
detailed visual inspection for broken fasteners, an open hole high 
frequency eddy current (HFEC) inspection of certain fastener holes 
in the frame inner chord to detect any cracking of structure, and a 
surface HFEC inspection of the frame web to detect any cracking.


    Note 5:  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.''


    Note 6:  The alert service bulletin gives instructions to 
perform an open hole inspection, but does not give instructions to 
oversize the fastener hole after the inspection. This will keep 
sufficient material to oversize the hole at a later date when the 
modification work is accomplished.

    (1) For airplanes that have accumulated fewer than 10,000 total 
flight cycles as of the effective date of this AD: Inspect prior to 
the accumulation of 10,000 total flight cycles, or within 1,000 
flight cycles after the effective date of this AD, whichever occurs 
later.
    (2) For airplanes that have accumulated between 10,000 and 
20,000 total flight cycles as of the effective date of this AD: 
Inspect prior to the accumulation of 11,000 total flight cycles, or 
within 750 flight cycles after the effective date of this AD, 
whichever occurs later.
    (3) For airplanes that have accumulated more than 20,000 total 
flight cycles as of the effective date of this AD: Inspect prior to 
the accumulation of 20,750 total flight cycles, or within 500 flight 
cycles after the effective date of this AD, whichever occurs later.
    (b) For Group 1 airplanes, as identified in Boeing Alert Service 
Bulletin 747-53A2416, Revision 1, dated May 6, 1999, on which the 
extended chord reinforcement strap modification specified in Boeing 
Service Bulletin 747-53-2066, dated June 28, 1972, has not been 
accomplished or on which the extended chord reinforcement strap 
modification was accomplished after the accumulation of 10,000 total 
flight cycles: Accomplish the surface HFEC inspection and the open 
hole HFEC inspection, as applicable, of the frames at the top of the 
inner chord reinforcement strap to detect any cracking of structure, 
in accordance with Figure 6 of the alert service bulletin at the 
applicable time specified in either paragraph (b)(1) or (b)(2) of 
this AD. Repeat the inspections thereafter at intervals not to 
exceed 800 flight cycles.
    (1) For airplanes that have accumulated 20,000 total flight 
cycles or fewer as of the effective date of this AD: Inspect prior 
to the accumulation of 16,000 total flight cycles, or within 500 
flight cycles after the effective date of this AD, whichever occurs 
later.
    (2) For airplanes that have accumulated more than 20,000 total 
flight cycles as of the effective date of this AD: Inspect prior to 
the accumulation of 20,500 total flight cycles, or within 250 flight 
cycles after the effective date of this AD, whichever occurs later.

Repair

    (c) If any broken fastener or cracking of structure is detected 
during the inspections required by paragraph (a) or (b) of this AD, 
prior to further flight, 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.

Alternative Methods 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 7:  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 shall be done in accordance with Boeing 
Alert Service Bulletin 747-53A2416, Revision 1, dated May 6, 1999. 
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.
    (g) This amendment becomes effective on March 7, 2000.

    Issued in Renton, Washington, on January 20, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-1765 Filed 1-31-00; 8:45 am]
BILLING CODE 4910-13-U