[Federal Register Volume 65, Number 84 (Monday, May 1, 2000)]
[Rules and Regulations]
[Pages 25281-25284]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-10285]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-231-AD; Amendment 39-11707; AD 2000-08-21]
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 all Boeing Model 747 series airplanes, that requires 
repetitive inspections to detect cracking of the forward and aft inner 
chords and the splice fitting of the forward inner chord of the station 
2598 bulkhead, and repair, if necessary. This amendment is prompted by 
reports of fatigue cracking found in those areas. The actions specified 
by this AD are intended to detect and correct such cracking, which 
could result in reduced structural capability of the bulkhead and the 
inability of the structure to carry horizontal stabilizer flight loads.

DATES: Effective June 5, 2000.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 5, 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

[[Page 25282]]

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 all Boeing Model 747 series 
airplanes was published in the Federal Register on November 5, 1999 (64 
FR 60386). That action proposed to require repetitive inspections to 
detect cracking of the forward and aft inner chords and the splice 
fitting of the forward inner chord of the station 2598 bulkhead, 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 comments received.

Request to Reference New Service Information

    One commenter requests that the proposed AD be revised to reference 
Boeing Alert Service Bulletin 747-53A2427, Revision 1, dated October 
28, 1999. (The original issue of Boeing Alert Service Bulletin 747-
53A2427, dated December 17, 1998, was referenced in the proposal as the 
appropriate source of service information for the proposed actions.)
    The FAA concurs with the commenter's request. Since the issuance of 
the proposed rule, the FAA has reviewed and approved Boeing Alert 
Service Bulletin 747-53A2427, Revision 1. Revision 1 of the alert 
service bulletin is substantially similar to the original issue. 
However, Revision 1 includes instructions for a one-time high frequency 
eddy current (HFEC) and repetitive detailed visual inspections to 
detect cracking of the splice fitting of the forward inner chord of the 
station 2598 bulkhead. Though not described in the original issue of 
the alert service bulletin, such inspections of the splice fitting were 
described in the proposed rule, so adding references to Revision 1 of 
the alert service bulletin to this final rule would not add any 
additional requirements beyond those that were proposed. Thus, 
paragraphs (a), (b), and (c) of this final rule have been revised to 
reference both the original issue and Revision 1 of the alert service 
bulletin as appropriate sources of service information for the 
requirements of this AD.
    In addition, the same commenter requests that the FAA make several 
specific changes to paragraphs (a) and (b) of the proposed rule:
    <bullet> Revise paragraph (a)(1) to refer to Figure 2, Steps 1 and 
2, of Boeing Alert Service Bulletin 747-53A2427, Revision 1;
    <bullet> Revise paragraph (a)(2) to refer to Figure 2, View C and 
View A, of Boeing Alert Service Bulletin 747-53A2427, Revision 1;
    <bullet> Revise paragraph (b)(1) to refer to Figure 3, Steps 1 and 
2, of Boeing Alert Service Bulletin 747-53A2427, Revision 1; and
    <bullet> Revise paragraph (b)(2) to refer to Figure 2, View C and 
View A, of Boeing Alert Service Bulletin 747-53A2427, Revision 1.

    The commenter states that these changes will make inspection 
instructions more explicit.
    The FAA concurs with the commenter's request, and references to 
specific figures and steps contained in Revision 1 of the alert service 
bulletin have been included in paragraphs (a) and (b) of this final 
rule accordingly. However, for consistency, where the commenter 
recommends ``View C and View A'' in its suggested revisions to 
paragraphs (a)(2) and (b)(2) of the proposed AD, the FAA instead has 
revised those paragraphs to refer to ``Step 3'' of the figures.

Request to Delete Notes

    The same commenter that requests that the FAA revise the proposed 
rule to reference new service information also requests that the FAA 
delete ``NOTE 2'' and ``NOTE 4'' of the proposed rule. These notes 
explain that inspection areas specified in paragraphs (a)(2) and (b)(2) 
of the proposed rule are not highlighted in certain figures in the 
original issue of the alert service bulletin. In Revision 1 of the 
alert service bulletin, the figures to which these notes refer have 
been updated to show the subject inspection areas. The commenter cites 
no justification for this request, but the FAA infers that the 
commenter considers ``NOTE 2'' and ``NOTE 4'' no longer necessary.
    The FAA does not concur with the commenter's request. As stated 
previously, this final rule has been revised to reference both the 
original issue and Revision 1 of the alert service bulletin as 
appropriate sources of service information. The information in ``NOTE 
2'' and ``NOTE 4'' is still correct for the original issue of the alert 
service bulletin. No change to the final rule is necessary in this 
regard.

Request to Clarify Repair Method

    One commenter requests that the FAA revise paragraph (d) of the 
proposed rule to allow repairs of cracking of the aft inner chord to be 
accomplished in accordance with the applicable chapters of the Boeing 
747 Structural Repair Manual (SRM) referenced in Boeing Alert Service 
Bulletin 747-53A2427. The commenter states that, without clarification, 
paragraph (d) of the proposal may be interpreted to require approval by 
the Manager of the FAA's Seattle Aircraft Certification Office (ACO) 
for repairs of cracking of the aft inner chord because the alert 
service bulletin provides the option to contact Boeing for repair data 
instead of using the SRM.
    The FAA does not concur with the commenter that any change is 
necessary. Paragraph (c) of the proposed rule (and this final rule) 
states that any cracking detected during the inspections required by 
paragraph (a)(1) or (b)(1) of this AD must be repaired in accordance 
with the alert service bulletin, except as provided by paragraph (d) of 
this AD. The FAA considers paragraph (d) of this AD to apply to cracks 
on the aft inner chord only if those cracks cannot be repaired in 
accordance with the chapters of the SRM listed in the alert service 
bulletin. 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.

Interim Action

    This is considered to be interim action. The manufacturer has 
advised that it currently is developing a modification that will 
positively address the unsafe condition addressed by this AD. Once this 
modification is developed, approved, and available, the FAA may 
consider additional rulemaking.

Cost Impact

    There are approximately 1,301 Model 747 series airplanes of the 
affected

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design in the worldwide fleet. The FAA estimates that 260 airplanes of 
U.S. registry will be affected by this AD.
    It will take approximately 2 work hours per airplane to accomplish 
the required HFEC inspection, at an average labor rate of $60 per work 
hour. Based on these figures, the cost impact of this inspection on 
U.S. operators is estimated to be $31,200, or $120 per airplane.
    It will take approximately 2 work hours per airplane to accomplish 
the required detailed visual inspections, at an average labor rate of 
$60 per work hour. Based on these figures, the cost impact of this 
inspection on U.S. operators is estimated to be $31,200, or $120 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:

2000-08-21  Boeing: Amendment 39-11707. Docket 99-NM-231-AD.

    Applicability: All Model 747 series airplanes, 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 (e) 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 forward and aft inner 
chords and the splice fitting of the forward inner chord of the 
station 2598 bulkhead, which could result in reduced structural 
capability of the bulkhead and the inability of the structure to 
carry horizontal stabilizer flight loads, accomplish the following:

Initial Inspection

    (a) Prior to the accumulation of 13,000 total flight cycles, or 
within 1,000 flight cycles after the effective date of this AD, 
whichever occurs later: Accomplish the requirements specified in 
paragraphs (a)(1) and (a)(2) of this AD.
    (1) Perform a high frequency eddy current inspection (HFEC) to 
detect cracking of the forward and aft inner chords of the station 
2598 bulkhead, in accordance with Boeing Alert Service Bulletin 747-
53A2427, dated December 17, 1998; or in accordance with Figure 2, 
Steps 1 and 2, of Boeing Alert Service Bulletin 747-53A2427, 
Revision 1, dated October 28, 1999.
    (2) Perform an HFEC inspection to detect cracking of the splice 
fitting along the upper and lower attachment to the forward inner 
chord of the station 2598 bulkhead, as shown in Figure 2, Detail A, 
of Boeing Alert Service Bulletin 747-53A2427, dated December 17, 
1998; or in accordance with Figure 2, Step 3, of Boeing Alert 
Service Bulletin 747-53A2427, Revision 1, dated October 28, 1999.

    Note 2: Operators should note that although the splice fitting 
is NOT highlighted in Figure 2, Detail A, of Boeing Alert Service 
Bulletin 747-53A2427, datedDecember 17, 1998, as it is in Figure 2 
of Boeing Alert Service Bulletin 747-53A2427, Revision 1, dated 
October 28, 1999, the inspection required by paragraph (a)(2) of 
this AD must still be accomplished.

Repetitive Inspections

    (b) Within 3,000 flight cycles after accomplishment of the 
inspections required by paragraph (a) of this AD: Accomplish the 
inspections specified in paragraphs (b)(1) and (b)(2) of this AD. 
Repeat the inspection thereafter at intervals not to exceed 3,000 
flight cycles.
    (1) Perform a detailed visual inspection to detect cracking of 
the forward and aft inner chords of the station 2598 bulkhead, in 
accordance with Boeing Alert Service Bulletin 747-53A2427, dated 
December 17, 1998; or in accordance with Figure 3, Steps 1 and 2, of 
Boeing Alert Service Bulletin 747-53A2427, Revision 1, dated October 
28, 1999.

    Note 3: 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.''

    (2) Perform a detailed visual inspection to detect cracking of 
the splice fitting along the upper and lower attachment to the 
forward inner chord of the station 2598 bulkhead, as shown in Figure 
3, Detail A, of Boeing Alert Service Bulletin 747-53A2427, dated 
December 17, 1998; or in accordance with Figure 3, Step 3, of Boeing 
Alert Service Bulletin 747-53A2427, Revision 1, dated October 28, 
1999.

    Note 4: Operators should note that although the splice fitting 
is NOT highlighted in Figure 3, Detail A, of Boeing Alert Service 
Bulletin 747-53A2427, dated December 17, 1998, as it is in Figure 3 
of Boeing Alert Service Bulletin 747-53A2427, Revision 1, dated 
October 28, 1999, the inspections required by paragraph (b)(2) of 
this AD must still be accomplished.

Repair

    (c) If any cracking is detected during the inspections required 
by paragraph (a)(1) or (b)(1) of this AD, prior to further flight, 
repair in accordance with Boeing Alert Service Bulletin 747-53A2427, 
dated December 17, 1998, or

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Revision 1, dated October 28, 1999; except as provided by paragraph 
(d) of this AD.
    (d) If any cracking is detected during the inspections required 
by paragraph (a)(2) or (b)(2) of this AD, or where the alert service 
bulletin specifies that the manufacturer may be contacted for 
disposition of certain repair conditions, 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 (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, or a Boeing DER, 
as required by this paragraph, the approval letter must specifically 
reference this AD.

Alternative Methods of Compliance

    (e) 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 5: 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

    (f) 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

    (g) Except as provided by paragraph (d) of this AD, the actions 
shall be done in accordance with Boeing Alert Service Bulletin 747-
53A2427, dated December 17, 1998, or Boeing Alert Service Bulletin 
747-53A2427, Revision 1, dated October 28, 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.

Effective Date

    (h) This amendment becomes effective on June 5, 2000.

    Issued in Renton, Washington, on April 19, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-10285 Filed 4-28-00; 8:45 am]
BILLING CODE 4910-13-U