[Federal Register Volume 69, Number 121 (Thursday, June 24, 2004)]
[Rules and Regulations]
[Pages 35237-35239]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-13866]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NM-149-AD; Amendment 39-13682; AD 2004-13-02]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 747-100, -200B, and -200F 
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 747-100, -200B, and -200F series 
airplanes. This action requires initial and repetitive inspections to 
find discrepancies in the upper and lower skins of the fuselage lap 
joints, and repair if necessary. This action is necessary to find and 
fix such discrepancies, which could result in sudden fracture and 
failure of a lap joint and rapid in-flight decompression of the 
airplane fuselage. This action is intended to address the identified 
unsafe condition.

DATES: Effective July 29, 2004.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 29, 2004.

ADDRESSES: The service information referenced in this AD may be 
obtained from Boeing Commercial Airplanes, 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: Nick Kusz, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 
917-6432; fax (425) 917-6590.

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 747-100, -
200B, and -200F series airplanes was published in the Federal Register 
on July 2, 2003 (68 FR 39483). That action proposed to require initial 
and repetitive inspections to find discrepancies in the upper and lower 
skins of the fuselage lap joints, 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.

Request To Withdraw the Notice of Proposed Rulemaking

    One commenter states that the proposed rule, as it applies to Model 
747 series airplanes, is unnecessary, will not improve safety, and 
imposes an undue burden on airplane operators. The commenter suggests 
that there is a tenuous connection between the 737 incident and the 747 
fleet. The commenter further states that Model 747 series airplanes 
have a stronger design than Model 737 series airplanes; that Model 747 
series airplanes have existing modifications and modification 
requirements; and that Model 747 series airplanes are better maintained 
by U.S. operators. In addition, this commenter recently completed 
``full modification'' of eighteen upper lobe lap joints on an affected 
Model 747 series airplane and found no evidence of scratches.
    The FAA infers from these comments that the commenter is requesting 
that the proposed rule be withdrawn. We do not agree. To date, no 
reports of cracks and scratches in the subject area have been found on 
Model 747 series airplanes. In consideration of this fact, we specified 
a longer compliance time in this AD for Model 747 series airplanes than 
the compliance time for Model 737 series airplanes specified in AD 
2000-17-04, amendment 39-11878 (65 FR 51750, August 25, 2002). We chose 
repetitive intervals of 72 months for the required low frequency eddy 
current (LFEC) inspections in order to minimize the effect on the 
operators while still providing an adequate level of safety. In 
addition, we determined that the possibility of scratches that initiate 
during manufacture exists for any cold-bonded adhesive skin panel, and 
that there have been numerous reports of corrosion on cold bonded skin 
panels in Boeing Model 747 series airplanes. Corrosion has also been 
reported on Boeing Model 747 series airplanes on which full 
modification has previously been accomplished per AD 90-06-06, 
amendment 39-6490 (55 FR 8374, March 7, 1990); and AD 94-12-09 
amendment 39-8937 (59 FR 30285, June 13, 1994). For these reasons, it 
is both warranted and necessary to issue this AD.

Remove Certain Inspection Requirements

    The same commenter requests that the LFEC inspections for corrosion 
at the upper fastener rows should not be required at locations that 
have had ``full modifications'' accomplished per Boeing Alert Service 
Bulletin 747-53A2267, dated March 28, 1986

[[Page 35238]]

(required by AD 94-17-01, amendment 39-8996 (59 FR 41653, August 15, 
1994)), or Boeing Service Bulletin 747-53-2307, Revision 1, dated 
August 27, 1992 (required by AD 94-12-09). The commenter states that 
the ``full modifications'' are sufficient to detect and remove damage, 
and that the post-modification inspections required by AD 94-12-09 and 
the SSID AD (AD 94-15-18, amendment 39-8989, 59 FR 41233, August 11, 
1994)) provide an equivalent level of safety in detecting subsequent 
damage.
    We do not agree that the external LFEC inspections should not be 
required for operators that have accomplished the modifications 
required by Boeing Alert Service Bulletin 747-53A2267 or Boeing Service 
Bulletin 747-53-2307. We have received reports from the manufacturer of 
corrosion on airplanes on which the full modification had been 
accomplished. While the re-sealing process included in the full 
modification does provide some level of improvement in surface 
protection, it does not provide enough of an improvement to prevent 
corrosion.
    We also do not agree that the post-modification inspections 
required by AD 94-12-09 and the SSID AD (AD 94-15-18) provide an 
equivalent level of safety. The post-modification external high 
frequency eddy current (HFEC) inspections required by AD 94-12-09 and 
AD 94-17-01 address cracks only in the upper row on the surface of the 
upper skin. The external LFEC inspections required by this AD address 
corrosion beneath the surface, at the interface between the upper and 
lower skins. We have not changed the final rule regarding these issues.

Include Alternative Method of Compliance (AMOC) for Repaired Airplanes

    The same commenter suggests that the proposed AD include specific 
instructions for conducting inspections where existing repairs may 
interfere with or obstruct the required inspections. The commenter also 
suggests that these potential obstructions will result in an exorbitant 
number of requests for AMOCs, and that the industry and the FAA are ill 
equipped to handle the number of requests. Further, the manufacturer 
has informed the commenter that a revision to Boeing Alert Service 
Bulletin 747-53A2463 (which is referenced in this AD as the appropriate 
source of service information for the required actions) is being 
prepared to include instructions to account for existing repairs.
    While we agree that it would be preferable to cite specific 
instructions for inspections at repaired areas, we cannot include such 
instructions until we receive the revised service bulletin from the 
manufacturer. At that time, we will review the revised service bulletin 
and, upon our approval of the new requirements, we will consider 
further rulemaking. We have not changed the final rule regarding this 
issue.

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.

Change to Labor Rate Estimate

    We have reviewed the figures we have used over the past several 
years to calculate AD costs to operators. To account for various 
inflationary costs in the airline industry, we find it necessary to 
increase the labor rate used in these calculations from $60 per work 
hour to $65 per work hour. The cost impact information, below, reflects 
this increase in the specified hourly labor rate.

Cost Impact

    There are approximately 86 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 55 airplanes of U.S. registry 
will be affected by this proposed AD, that it will take approximately 
5,334 work hours per airplane to accomplish the inspections, and that 
the average labor rate is $65 per work hour. Based on these figures, 
the cost impact of this AD on U.S. operators is estimated to be 
$19,069,050, or $346,710 per airplane.
    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. The cost impact figures discussed 
in AD rulemaking actions represent only the time necessary to perform 
the specific actions actually required by the AD. These figures 
typically do not include incidental costs, such as the time required to 
gain access and close up, planning time, or time necessitated by other 
administrative actions.

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

0
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

0
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]

0
2. Section 39.13 is amended by adding the following new airworthiness 
directive:

2004-13-02 Boeing: Amendment 39-13682. Docket 2002-NM-149-AD.
    Applicability: Model 747-100, -200B, and -200F series airplanes, 
as listed in Boeing Alert Service Bulletin 747-53A2463, dated March 
7, 2002; certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To find and fix discrepancies in the upper and lower skins of 
the fuselage lap joints, which could result in sudden fracture and 
failure of a lap joint and rapid in-flight decompression of the 
airplane fuselage, accomplish the following:

Initial and Repetitive Inspections

    (a) Do the applicable (initial and repetitive) inspections as 
specified in Figures 2 through 8, as applicable, of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 747-
53A2463, including Appendices A, B, and C, dated March 7, 2002, to 
find discrepancies (cracking and corrosion) in the upper and lower 
skins of the fuselage lap joints. Do the inspections at the 
applicable times specified in Figure 1 of the

[[Page 35239]]

Accomplishment Instructions of the alert service bulletin, in 
accordance with the alert service bulletin; except that where Figure 
1 specifies a compliance time of ``after the release date of this 
service bulletin,'' this AD requires a compliance time of ``after 
the effective date of this AD.'' Where Figure 1 specifies a 
compliance time of ``flight cycles'' this AD requires a compliance 
time of ``total flight cycles.''
    (b) Where Boeing Alert Service Bulletin 747-53A2463, including 
Appendices A, B, and C, dated March 7, 2002, specifies that the 
manufacturer may be contacted for certain inspection procedures, 
inspect per a method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA; or per 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.

Adjustments to Compliance Time: Cabin Differential Pressure

    (c) For the purposes of calculating the compliance threshold and 
repetitive interval for the inspections required by paragraph (a) of 
this AD: Flight cycles in which cabin differential pressure is at 
2.0 pounds per square inch (psi) or less need not be counted when 
determining the number of flight cycles that have occurred on the 
airplane, provided that flight cycles with momentary spikes in cabin 
differential pressure above 2.0 psi are included as full pressure 
flight cycles. For this provision to apply, all cabin pressure 
records must be maintained for each airplane. No fleet-averaging of 
cabin pressure is allowed.

Repair

    (d) Before further flight, repair any discrepancy (cracking or 
corrosion) found during any inspection required by paragraph (a) of 
this AD, per the Accomplishment Instructions of Boeing Alert Service 
Bulletin 747-53A2463, including Appendices A, B, and C, dated March 
7, 2002. If any discrepancy is found and the alert service bulletin 
specifies that the manufacturer may be contacted for disposition of 
certain repairs, before further flight, repair per a method approved 
by the Manager, Seattle ACO; or per data meeting the type 
certification basis of the airplane approved by a Boeing Company DER 
who has been authorized by the Manager, Seattle ACO, to make such 
findings.

Alternative Methods of Compliance

    (e) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, 
is authorized to approve alternative methods of compliance for this 
AD.

Incorporation by Reference

    (f) Unless otherwise specified in this AD, the actions shall be 
done in accordance with Boeing Alert Service Bulletin 747-53A2463, 
including Appendices A, B, and C, dated March 7, 2002. 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 Airplanes, 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

    (g) This amendment becomes effective on July 29, 2004.

    Issued in Renton, Washington, on June 9, 2004.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-13866 Filed 6-23-04; 8:45 am]
BILLING CODE 4910-13-P