[Federal Register Volume 70, Number 216 (Wednesday, November 9, 2005)]
[Proposed Rules]
[Pages 67952-67954]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-22306]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-22874; Directorate Identifier 2005-NM-173-AD]
RIN 2120-AA64


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

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain Boeing Model 777-200 and -300 series airplanes. This 
proposed AD would 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. This proposed 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 proposing 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.

DATES: We must receive comments on this proposed AD by December 27, 
2005.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
    <bullet> DOT Docket Web site: Go to  http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
    <bullet> Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
    <bullet> Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, 
Washington, DC 20590.
    <bullet> Fax: (202) 493-2251.
    <bullet> Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, 
Washington 98124-2207, for the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: John Vann, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone 
(425) 917-6513; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any relevant written data, views, or 
arguments regarding this proposed AD. Send your comments to an address 
listed in the ADDRESSES section. Include the docket number ``FAA-2005-
22874; Directorate Identifier 2005-NM-173-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed AD. Using the search function of 
that web site, anyone can find and read the comments in any of our 
dockets, including the name of the individual who sent the comment (or 
signed the comment on behalf of an association, business, labor union, 
etc.). You may review DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit http://dms.dot.gov.

Examining the Docket

    You may examine the 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 DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

Discussion

    We have received a report indicating that damaged/deteriorated 
thermal insulation blankets and discolored fairing lower webs were 
found in the aft fairings of engine struts on several Model 777-200 and 
-300 series airplanes. Gaps in the segmented heat shield in the strut 
aft fairings allow engine primary/main exhaust to enter the heat shield 
cavity in the strut aft fairing. The temperature of the exhaust that 
leaks into the heat shield cavity exceeds the insulation blankets' 
maximum design tolerance. Since the insulation blankets provide thermal 
protection for the aluminum fairing lower web, degradation of an 
insulation blanket allows thermal distress of the lower web and 
eventually, cracking of the lower web. A cracked lower web is

[[Page 67953]]

also a possible leak path for hydraulic fluid to come into direct 
contact with the heat shield, the temperature of which can exceed the 
hydraulic fluid's auto-ignition temperature (750 degrees Fahrenheit). 
Gaps in the heat shield, if not corrected, could result in cracked 
fairing lower webs and consequently leak flammable hydraulic fluid onto 
or near an ignition source and possibly result in an uncontrollable 
fire in the engine strut area.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 777-54-
0021, dated June 23, 2005. The service bulletin describes the following 
procedures:
    <bullet> Doing a general visual inspection of the lower web of the 
aft fairing for any discoloration and doing any related investigative 
and corrective action if necessary;
    <bullet> Doing a general visual inspection of the heat shield 
castings for any damage (crack(s), dent(s), gouge(s), warpage, or 
fretting) and doing any corrective action if necessary;
    <bullet> Installing gap cover strips; and
    <bullet> Replacing insulation blankets with new blankets.
    The related investigative action is a special detailed inspection 
for heat damage and for cracks at the fastener holes of areas with 
discolored paint or primer. The corrective action is to contact Boeing 
for repair instructions if any damage is found during the inspections.
    The corrective action for any damage found during an inspection of 
the heat shield castings involves contacting Boeing for instructions on 
repairing or replacing damaged heat shields before further flight.
    Replacing the insulation blankets with new insulation blankets may 
involve modifying the configuration of the insulation blanket velcro 
strips into a new configuration if the strips were previously installed 
in a particular configuration before 1997.
    Accomplishing the actions specified in the service information is 
intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require accomplishing the actions specified in the service 
information described previously, except as discussed under 
``Difference Between the Proposed AD and the Service Bulletin.''

Difference Between the Proposed AD and the Service Bulletin

    The service bulletin specifies that you may contact the 
manufacturer for instructions on how to repair certain conditions, but 
this proposed AD would require you to repair those conditions in one of 
the following ways:
    <bullet> Using a method that we approve; or
    <bullet> Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the Boeing Commercial Airplanes Delegation Option Authorization 
Organization who has been authorized by the FAA to make those findings.

Costs of Compliance

    There are about 294 airplanes of the affected design in the 
worldwide fleet. This proposed AD would affect about 72 airplanes of 
U.S. registry. The proposed actions would 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 proposed 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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 the proposed 
regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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 proposed 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, Safety.

The Proposed Amendment

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

Boeing: Docket No. FAA-2005-22874; Directorate Identifier 2005-NM-
173-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by December 
27, 2005.

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, dated June 23, 2005.

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.

[[Page 67954]]

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) in accordance with 
the Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 777-54-0021, dated June 23, 2005. Do any corrective or 
related investigative action before further flight in accordance 
with the service bulletin.
    (1) Do a general visual inspection of the lower web of the aft 
fairing for any discoloration and do any applicable related 
investigative and corrective action.
    (2) Do a general visual inspection of the heat shield castings 
for any damage (crack(s), dent(s), gouge(s), warpage, or fretting) 
and do any applicable corrective action.
    (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(s) is 
found during any inspection required by this AD, and Boeing Special 
Attention Service Bulletin 777-54-0021, dated June 23, 2005, 
specifies contacting Boeing for appropriate action: Before further 
flight, repair the damage using a method approved in accordance with 
the procedures specified in paragraph (h) of this AD.

Alternative Methods of Compliance (AMOCs)

    (h)(1) The Manager, Seattle Aircraft Certification Office (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.

    Issued in Renton, Washington, on October 26, 2005.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-22306 Filed 11-8-05; 8:45 am]
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