[Federal Register Volume 71, Number 185 (Monday, September 25, 2006)]
[Rules and Regulations]
[Pages 55727-55729]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-8122]



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Rules and Regulations
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Federal Register / Vol. 71, No. 185 / Monday, September 25, 2006 / 
Rules and Regulations

[[Page 55727]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-22874; Directorate Identifier 2005-NM-173-AD; 
Amendment 39-14769; AD 2006-19-12]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 777-200 and -300 Series 
Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Boeing Model 777-200 and -300 series airplanes. This AD 
requires inspecting the lower web of the aft fairing of engine struts 
for any discoloration and doing any related investigative and 
corrective action if necessary; inspecting the heat shield castings for 
any damage and doing any corrective action if necessary; installing gap 
cover strips; and replacing insulation blankets with new insulation 
blankets. This AD results from a report that several discolored fairing 
lower webs and some damaged/deteriorated insulation blankets were found 
in the aft fairings of engine struts. We are issuing this AD to prevent 
cracking of lower webs of the aft fairings, which could result in 
flammable hydraulic fluid leaking onto or near an ignition source, and 
possibly result in an uncontrollable fire in the engine strut area.

EFFECTIVE DATE: This AD becomes effective October 30, 2006.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of October 30, 
2006.

ADDRESSES: You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. 
Department of Transportation, 400 Seventh Street SW., Nassif Building, 
Room PL-401, Washington, DC.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Margaret Langsted, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6500; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Examining the Docket

    You may examine the airworthiness directive (AD) docket on the 
Internet at http://dms.dot.gov or in person at the Docket Management 
Facility office between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The Docket Management Facility office 
(telephone (800) 647-5227) is located on the plaza level of the Nassif 
Building at the street address stated in the ADDRESSES section.

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that would apply to certain Boeing Model 
777-200 and -300 series airplanes. That NPRM was published in the 
Federal Register on November 9, 2005 (70 FR 67952). That NPRM proposed 
to require inspecting the lower web of the aft fairing of engine struts 
for any discoloration and doing any related investigative and 
corrective action if necessary; inspecting the heat shield castings for 
any damage and doing any corrective action if necessary; installing gap 
cover strips; and replacing insulation blankets with new insulation 
blankets.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Supportive Comment

    One commenter, Boeing, concurs with the contents of the NPRM.

Request To Address Technical Discrepancies in the Service Bulletin

    Continental Airlines (CAL) concurs with the intent of the NPRM to 
mandate Boeing Special Attention Service Bulletin 777-54-0021, dated 
June 23, 2005, in an effort to minimize heat damage to the pylon aft 
fairing. CAL noted some technical discrepancies that may create 
problems for the operators if Service Bulletin 777-54-0021 is mandated 
as-is. CAL specifically noted that, in the procedures given for 
performing an inspection of the lower web for heat damage, there are no 
International Annealed Copper Standard (IACS) values given to determine 
whether the condition of the web material is acceptable for continued 
service. CAL considers a conductivity of 44 percent of IACS value or 
less acceptable for service. CAL coordinated these issues with Boeing 
for corrective action, confirmed that the issues would be corrected in 
the next revision of the service bulletin, and agreed to validate 
Service Bulletin 777-54-0021 for Boeing. CAL recommends that we either 
defer this rulemaking action until Revision 1 of the service bulletin 
is released, or incorporate the corrections of these discrepancies 
within the AD. CAL also ``would like to see verbiage in the ruling that 
will allow us to take credit'' for work accomplished on airplanes 
changed as shown in the initial release of the service bulletin.
    We agree that the initial release of Service Bulletin 777-54-0021 
has discrepancies that could create problems for operators if required 
as-is. Since the NPRM was published, Boeing has issued Boeing Special 
Attention Service Bulletin 777-54-0021, Revision 1, dated March 16, 
2006. Revision 1 of the service bulletin addresses the discrepancies 
noted by CAL. However, Revision 1 of the service bulletin recommends 
that the threshold criteria for the heat damage inspection be 42 
percent or less of IACS, not the 44 percent proposed by CAL. We have 
determined that we will require a 42 percent threshold in accordance 
with that service bulletin. We also have determined that no more work 
is necessary for airplanes modified in accordance with the initial 
release of the service bulletin. We have revised paragraphs (f) and (g) 
of this AD to reference Revision 1 of the service bulletin and have 
added paragraph (h)

[[Page 55728]]

to this AD to allow credit for previously accomplished actions in 
accordance with the initial release of the service bulletin, provided 
that the IACS threshold used is 42 percent or less.

Request To Extend Compliance Times for Airplanes With Boeing Service 
Bulletin 777-54A0015 Incorporated

    CAL requests that the AD make a distinction between affected GE-
engine-powered airplanes with and without the incorporation of Boeing 
Service Bulletin 777-54A0015, Revision 1, dated March 15, 2002. CAL 
states that according to the information in Service Bulletin 777-54-
0021, reports of discolored lower webs and deteriorated thermal 
blankets are all from airplanes that did not have Service Bulletin 777-
54A0015 incorporated. CAL notes that Service Bulletin 777-54A0015 
provides instructions to modify the cover plate of the Number 1 heat 
shield segment to block the through-flow of hot exhaust gas in the heat 
shield cavity, and replace the thermal insulation blankets to protect 
the area above from heat damage. CAL states that it incorporated these 
changes on all affected airplanes in its fleet between 2002 and 2003. 
CAL requests/recommends that we extend the compliance time from 12 
months to 24 months for airplanes that have incorporated Service 
Bulletin 777-54A0015.
    We do not agree to extend the compliance time. The incorporation of 
Service Bulletin 777-54A0015 on GE-engine-powered airplanes was 
intended to prevent elevated temperatures from the primary exhaust from 
passing into the strut aft fairing cavity through a gap between the 
strut aft fairing heat shield cover plate and the aft fairing lower 
web. The incorporation of Service Bulletin 777-54-0021, Revision 1, is 
intended to prevent the deterioration of new insulation blankets in the 
strut aft fairing. The insulation blankets, located on the bottom side 
of the fairing lower web and above the segmented heat shield, are used 
to reduce the temperature inside the strut aft fairing. Gaps in the 
segmented heat shield allow the engine's primary exhaust to enter the 
heat shield cavity. The flow path blockage provided by Service Bulletin 
777-54A0015 is entirely separate from the blockage provided by Service 
Bulletin 777-54-0021, Revision 1. We consider these two design changes 
independent and do not agree with extending the compliance time for 
those airplanes having incorporated Service Bulletin 777-54A0015. We 
have not revised this AD in this regard.

Clarification of Service Bulletin's Inclusion of Nutplate Inspection

    Service Bulletin 777-54-0021, Revision 1, includes in the general 
visual inspection for damage of the heat shield casting, a missing or 
loose nutplate as one criterion for damage. We consider this additional 
criterion a relieving action. Without the nutplate inspection in the 
general visual inspection for damage, a missing nutplate would be 
discovered during re-installation of the forward-most heat shield when 
fasteners would fail to be torqued to the correct torque value. Finding 
missing or loose nutplate(s) during the general visual inspection 
provides scheduling and economic benefits when compared to the cost of 
discovering missing nutplates after heat shield reinstallation.

Clarification of Additional Available Repair Method

    Service Bulletin 777-54-0021, Revision 1, also provides more 
detailed repair instructions that may be used for repair of conditions 
found during the inspections. We have revised paragraph (g) of this AD 
to allow repair in accordance with the repair instructions provided by 
Service Bulletin 777-54-0021, Revision 1.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    There are about 294 airplanes of the affected design in the 
worldwide fleet. This AD will affect about 72 airplanes of U.S. 
registry. The actions will take about 9 to 11 work hours per airplane, 
depending on engine manufacturer (configuration), at an average labor 
rate of $65 per work hour. Required parts would cost about $15,368 to 
$16,179 per airplane. Based on these figures, the estimated cost of the 
AD for U.S. operators is $1,148,616 to $1,216,368, or $15,953 to 
$16,894 per airplane.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD 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.
    For the reasons discussed above, I certify that this AD:
    (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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 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. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):


[[Page 55729]]


2006-19-12 Boeing: Amendment 39-14769. Docket No. FAA-2005-22874; 
Directorate Identifier 2005-NM-173-AD.

Effective Date

    (a) This AD becomes effective October 30, 2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 777-200 and -300 series 
airplanes, certificated in any category; as identified in Boeing 
Special Attention Service Bulletin 777-54-0021, Revision 1, dated 
March 16, 2006.

Unsafe Condition

    (d) This AD results from a report that several discolored 
fairing lower webs and some damaged/deteriorated insulation blankets 
were found in the aft fairings of engine struts. We are issuing this 
AD to prevent cracking of lower webs of the aft fairings, which 
could result in flammable hydraulic fluid leaking onto or near an 
ignition source, and possibly result in an uncontrollable fire in 
the engine strut area.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Inspection, Installation, and Replacement Actions

    (f) Except as provided by paragraph (g) of this AD: Within 12 
months after the effective date of this AD, do the actions specified 
in paragraphs (f)(1), (f)(2), (f)(3), and (f)(4) of this AD in 
accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 777-54-0021, Revision 1, dated March 16, 
2006.
    (1) Do a general visual inspection of the lower web of the aft 
fairing for any discoloration and do any related investigative 
action.
    (2) Do a general visual inspection of the heat shield castings 
for any damage (crack(s), dent(s), gouge(s), warpage, fretting, or 
missing/loose nutplates).
    (3) Install gap cover strips on the heat shield pans.
    (4) Replace insulation blankets on the heat shield pans with new 
insulation blankets.

Repair Instructions

    (g) If any damage, discoloration, heat damage, or crack is found 
during any inspection required by this AD: Before further flight, do 
all applicable corrective actions in accordance with a method 
approved by the Manager, Seattle Aircraft Certification Office 
(ACO), FAA, or in accordance with the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 777-54-0021, Revision 1, 
dated March 16, 2006.

Previously Accomplished Actions

    (h) Actions done before the effective date of this AD in 
accordance with Boeing Special Attention Service Bulletin 777-54-
0021, dated June 23, 2005, are acceptable for compliance with the 
requirements of paragraph (f) of this AD, except where the service 
bulletin does not provide an International Annealed Copper Standard 
(ICAS) value for determining the results of the inspection for heat 
damage, the maximum acceptable ICAS value is 42 percent.

Alternative Methods of Compliance (AMOCs)

    (i)(1) The Manager, Seattle ACO, FAA, has the authority to 
approve AMOCs for this AD, if requested in accordance with the 
procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with 14 CFR 
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.

Material Incorporated by Reference

    (j) You must use Boeing Special Attention Service Bulletin 777-
54-0021, Revision 1, dated March 16, 2006, to perform the actions 
that are required by this AD, unless the AD specifies otherwise. The 
Director of the Federal Register approved the incorporation by 
reference of this document in accordance with 5 U.S.C. 552(a) and 1 
CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, 
Seattle, Washington 98124-2207, for a copy of this service 
information. You may review copies at the Docket Management 
Facility, U.S. Department of Transportation, 400 Seventh Street SW., 
Room PL-401, Nassif Building, Washington, DC; on the Internet at 
http://dms.dot.gov; or at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on September 13, 2006.
Kevin M. Mullin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-8122 Filed 9-22-06; 8:45 am]
BILLING CODE 4910-13-P