[Federal Register: November 9, 2004 (Volume 69, Number 216)]
[Rules and Regulations]               
[Page 64852-64853]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09no04-11]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NM-106-AD; Amendment 39-13855; AD 2004-22-27]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 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 737-600, -700, -700C, -800, and -900 
series airplanes, that requires a general visual inspection for sealant 
at the interface between the diagonal brace fitting and the aft 
bulkhead and at the four bolts common to the interface. It also 
requires applying sealant if none is present or if it is not 
continuous. This action is necessary to prevent flammable fluid in the 
upper or rear pylon areas from leaking past unsealed areas and onto a 
hot engine nozzle, which could result in ignition of the fluid, causing 
an undetected and uncontrollable fire to spread into the engine struts. 
This action is intended to address the identified unsafe condition.

DATES: Effective December 14, 2004.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 14, 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 Federal 
Aviation Administration (FAA), Transport Airplane Directorate, Rules 
Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call (202) 741-6030, or go to: 
http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html
.


FOR FURTHER INFORMATION CONTACT: Doug Pegors, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6504; 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 737-600, -
700, -700C, -800, and -900 series airplanes was published in the 
Federal Register on May 3, 2004 (69 FR 24101). That action proposed to 
require a general visual inspection for sealant at the interface 
between the diagonal brace fitting and the aft bulkhead and at the four 
bolts common to the interface. It also proposed to require applying 
sealant if none is present or if it is not continuous.

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 Extend Compliance Time

    One commenter requests that the FAA extend the compliance time for 
the general visual inspection from 18 months or 3,500 flight cycles, 
whichever occurs first, to 24 months or 4,500 flight cycles, whichever 
occurs first. The commenter states that access is common for the 
proposed inspection and Boeing Maintenance Planning Document (MPD) 
tasks 54-040-1 through 54-050-02, dated February 10, 2004, and that it 
would be more cost efficient if the commenter could perform the 
inspection and MPD tasks during the same maintenance visit, every 24 
months.
    We do not agree with the request to extend the compliance time. The 
commenter provided no justification for the change other than for the 
convenience of its maintenance program. In developing an appropriate 
compliance time for this action, we considered the recommendation of 
the manufacturer, urgency associated with the subject unsafe condition, 
and the practical aspect of accomplishing the required inspection 
within a period of time that corresponds to the normal scheduled 
maintenance for most affected operators. However, under the provisions 
of paragraph (c) of the final

[[Page 64853]]

rule, we may approve requests for adjustments to the compliance time if 
data are submitted to substantiate that such an adjustment would 
provide an acceptable level of safety.

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.

Clarification of Changes to the Final Rule

    We have revised paragraph (a)(2) of the final rule and added new 
paragraph (a)(3) to eliminate any possible ambiguity created by use of 
the term ``and/or'' in the proposed AD.

Cost Impact

    There are approximately 946 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 436 airplanes of U.S. registry 
will be affected by this AD, that it will take approximately 2 work 
hours per airplane to accomplish the required actions, and that the 
average labor rate is $65 per work hour. Based on these figures, the 
cost impact of the AD on U.S. operators is estimated to be $56,680, or 
$130 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. Manufacturer warranty remedies may be available 
for labor costs associated with this AD. As a result, the costs 
attributable to this AD may be less than stated above.

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:

2004-22-27 Boeing: Amendment 39-13855. Docket 2003-NM-106-AD.

    Applicability: Model 737-600, -700, -700C, -800, and -900 series 
airplanes, line numbers 1 through 946 inclusive; certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent flammable fluid in the upper or rear pylon areas from 
leaking past unsealed areas and onto a hot engine nozzle, which 
could result in ignition of the fluid, causing an undetected and 
uncontrollable fire to spread into the engine struts; accomplish the 
following:

Inspection of Sealant

    (a) Within 18 months or 3,500 flight cycles after the effective 
date of this AD, whichever occurs first: Perform a general visual 
inspection for sealant at the interface of the diagonal brace 
fitting and the aft bulkhead and at the four bolts common to the 
interface, in accordance with the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 737-54-1039, Revision 1, 
dated October 10, 2002.
    (1) If the findings of the general visual inspection are as 
described in paragraphs (a)(1)(i) and (a)(1)(ii) of this AD, then no 
further action is required by this AD.
    (i) The seal is continuous or there is evidence of fay seal 
sqeeze out present.
    (ii) The bolts have evidence of sealant squeeze out or a cap 
seal exists.

Application of Fillet Seal

    (2) The seal is not continuous and there is no evidence of fay 
seal squeeze out present, before further flight, fillet seal around 
the interface of the diagonal brace fitting and the aft bulkhead, in 
accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-54-1039, Revision 1, dated October 
10, 2002.

Application of Cap Seal

    (3) If the bolts do not have evidence of sealant squeeze out and 
no cap seal exists, before further flight, cap seal the four bolts 
common to the interface, in accordance with the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-54-
1039, Revision 1, dated October 10, 2002.

Credit for Actions Accomplished per Previous Service Bulletin

    (b) Actions accomplished before the effective date of this AD 
per Boeing Special Attention Service Bulletin 737-54-1039, dated 
June 13, 2002, are acceptable for compliance with the corresponding 
actions of paragraph (a) of this AD.

Alternative Methods of Compliance (AMOC)

    (c) In accordance with 14 CFR 39.19, the Manager, Seattle 
Aircraft Certification Office, FAA, is authorized to approve AMOCs 
for this AD.

Incorporation by Reference

    (d) Unless otherwise specified in this AD, the actions shall be 
done in accordance with Boeing Special Attention Service Bulletin 
737-54-1039, Revision 1, dated October 10, 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 National Archives and Records Administration (NARA). For 
information on the availability of this material at NARA, call (202) 
741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html
.


Effective Date

    (e) This amendment becomes effective on December 14, 2004.

    Issued in Renton, Washington, on October 26, 2004.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 04-24626 Filed 11-8-04; 8:45 am]

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