
[Federal Register Volume 76, Number 13 (Thursday, January 20, 2011)]
[Proposed Rules]
[Pages 3566-3569]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-1119]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0026; Directorate Identifier 2010-NM-104-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 777-200 and -
300 Series Airplanes Equipped With Pratt and Whitney Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Model 777-200 and -300 series airplanes. This proposed AD would 
require repetitive inspections for

[[Page 3567]]

hydraulic fluid contamination of the interior of the strut disconnect 
assembly; repetitive inspections for discrepancies of the interior of 
the strut disconnect assembly, if necessary; repetitive inspections of 
the exterior of the strut disconnect assembly for cracks, if necessary; 
and corrective action if necessary. This proposed AD also provides an 
optional terminating action for the inspections. This proposed AD 
results from reports of system disconnect boxes that have been 
contaminated with hydraulic fluid and, in one incident, led to 
subsequent cracking of titanium parts in the system disconnect 
assembly. We are proposing this AD to detect and correct hydraulic 
fluid contamination, which can cause cracking of titanium parts in the 
system disconnect assembly, resulting in compromise of the engine 
firewall. A cracked firewall can allow fire in the engine area to enter 
the strut and can lead to an uncontained engine strut fire if flammable 
fluid is present. Cracking of the disconnect box may also reduce the 
effectiveness of the fire extinguishing system in the engine 
compartment and could contribute to an uncontained engine fire. In 
addition, a cracked disconnect box can leak flammable fluids into the 
engine core, which can initiate an engine fire, and lead to one or both 
fire conditions discussed above.

DATES: We must receive comments on this proposed AD by March 7, 2011.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; 
Internet https://www.myboeingfleet.com. You may review copies of the 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information 
on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (telephone 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Kevin Nguyen, Propulsion Branch, ANM-
140S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind 
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6501; 
fax (425) 917-6590.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2011-0026; 
Directorate Identifier 2010-NM-104-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We have received reports of system disconnect boxes that have been 
contaminated with hydraulic fluid. One operator has found cracks in the 
system disconnect assembly bulkheads and lower skin panel. Subsequent 
analysis at Boeing found hydrogen enbrittlement of the system 
disconnect assembly bulkheads and lower skin panel. The system 
disconnect assembly is made from titanium and is located near the hot 
engine core of the engine where temperatures can exceed 270 degrees 
Fahrenheit. The presence of hydraulic fluid and temperature above 270 
degrees Fahrenheit can result in hydrogen embrittlement of the titanium 
system disconnect assembly. Hydrogen embrittlement combined with a high 
sonic vibration environment can result in cracking of the system 
disconnect assembly. The system disconnect assembly is a box where 
hydraulic, fuel, and electrical connections are made between the engine 
and the strut. This box acts as a firewall between the engine 
compartment and the strut. The engine compartment has a fire 
extinguishing system while the strut does not. The strut is considered 
a flammable leakage zone where flammable fluids may be present. These 
fluids are subsequently drained from the strut and system disconnect 
box. A cracked firewall can allow fire in the engine area to enter the 
strut and can lead to an uncontained engine strut fire if flammable 
fluid is present. Cracking of the disconnect box may also reduce the 
effectiveness of the fire extinguishing system in the engine 
compartment and could contribute to an uncontained engine fire. In 
addition, a cracked disconnect box can leak flammable fluids into the 
engine core, which can initiate an engine fire, and lead to one or both 
fire conditions discussed above.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 777-54A0024, 
Revision 1, dated November 4, 2010. This service bulletin describes 
procedures for doing repetitive general visual inspections for 
hydraulic fluid contamination of the interior of the strut disconnect 
assembly; repetitive detailed inspections for discrepancies (e.g., 
hydraulic fluid coking, heat discoloration, cracks, and etching or 
pitting) of the interior of the strut disconnect assembly, if certain 
conditions are found; repetitive detailed inspections of the exterior 
of the strut disconnect assembly for cracks; and corrective action, if 
certain conditions are found. The corrective action is replacing the 
titanium system disconnect assembly with an Inconel system disconnect 
assembly. If accomplished, the replacement will eliminate the potential 
for hydrogen embrittlement and subsequent cracking, and would eliminate 
the need for the inspections of the titanium strut disconnect assembly.

FAA's Determination and Requirements of This Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or

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develop in other products of these same type designs. This proposed AD 
would require accomplishing the actions specified in the service 
information described previously.

Costs of Compliance

    We estimate that this proposed AD would affect 53 airplanes of U.S. 
registry. We also estimate that it would take about 48 work-hours per 
product to comply with this proposed AD. The average labor rate is $85 
per work-hour. Required parts would cost about $122,617 per product. 
Based on these figures, we estimate the cost of this proposed AD to the 
U.S. operators to be $6,714,941, or $122,697 per product.

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 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 this 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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, 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 FAA amends Sec.  39.13 by adding the following new AD:

The Boeing Company: Docket No. FAA-2011-0026; Directorate Identifier 
2010-NM-104-AD.

Comments Due Date

    (a) We must receive comments by March 7, 2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 777-200 and -300 
series airplanes, certificated in any category; equipped with Pratt 
and Whitney engines; as identified in Boeing Alert Service Bulletin 
777-54A0024, Revision 1, dated November 4, 2010.

Subject

    (d) Air Transport Association (ATA) of America Code 54: 
Nacelles/Pylons.

Unsafe Condition

    (e) This AD results from reports of system disconnect boxes that 
have been contaminated with hydraulic fluid, in which one case a 
crack was found. The Federal Aviation Administration is issuing this 
AD to detect and correct hydraulic fluid contamination, which can 
cause cracking of titanium parts in the system disconnect assembly, 
resulting in compromise of the engine firewall. A cracked firewall 
can allow fire in the engine area to enter the strut and can lead to 
an uncontained engine strut fire if flammable fluid is present. 
Cracking of the disconnect box may also reduce the effectiveness of 
the fire extinguishing system in the engine compartment and could 
contribute to an uncontained engine fire. In addition, a cracked 
disconnect box can leak flammable fluids into the engine core, which 
can initiate an engine fire and lead to one or both fire conditions 
discussed above.

Compliance

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

Inspections and Corrective Actions

    (g) Within 12 months after the effective date of this AD: Do a 
general visual inspection for hydraulic fluid contamination of the 
interior of the strut disconnect assembly, in accordance with Part 1 
of the Accomplishment Instructions of Boeing Alert Service Bulletin 
777-54A0024, Revision 1, dated November 4, 2010.
    (1) For airplanes on which no hydraulic fluid contamination is 
found (Condition 1): Repeat the general visual inspection required 
by paragraph (g) of this AD thereafter at intervals not to exceed 
6,000 flight cycles or 750 days, whichever occurs first.
    (2) For airplanes on which hydraulic fluid contamination is 
found (Condition 2): Before further flight, do a detailed inspection 
for discrepancies (e.g., hydraulic fluid coking, heat discoloration, 
cracks, and etching or pitting) of the interior of the strut 
disconnect assembly, in accordance with Part 2 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 777-54A0024, Revision 
1, dated November 4, 2010.
    (i) For airplanes on which no discrepancy is found during the 
inspection required by paragraph (g)(2) of this AD (Condition 2A): 
Repeat the detailed inspection required by paragraph (g)(2) of this 
AD thereafter at intervals not to exceed 6,000 flight cycles or 750 
days, whichever occurs first.
    (ii) For airplanes on which hydraulic fluid coking or heat 
discoloration is found but no cracking, etching, or pitting is found 
during the inspection required by paragraph (g)(2) of this AD 
(Condition 2B): Do the actions required by paragraph (g)(2)(ii)(A) 
and (g)(2)(ii)(B) of this AD.
    (A) Within 300 flight cycles after doing the inspection required 
by paragraph (g)(2) of this AD: Do a detailed inspection of the 
exterior of the strut disconnect assembly for cracks, in accordance 
with Part 3 of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 777-54A0024, Revision 1, dated November 4, 2010; 
and repeat the detailed inspection thereafter at intervals not to 
exceed 300 flight cycles.
    (B) Within 6,000 flight cycles or 750 days after hydraulic fluid 
coking and/or heat discoloration was found during the inspection 
required by paragraph (g)(2) of this AD, whichever occurs first: 
Replace the titanium system disconnect assembly with an Inconel 
system, in accordance with Part 4 of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 777-54A0024, Revision 1, dated 
November 4, 2010.
    (h) For airplanes on which any crack, etching, or pitting is 
found during any inspection required by paragraph (g)(2) or 
(g)(2)(ii)(A) of this AD (Condition 3): Before further flight, 
replace the titanium system disconnect assembly with an Inconel 
system, in accordance with Part 4 of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 777-54A0024, Revision 1, dated 
November 4, 2010.

Optional Terminating Action

    (i) Replacing the titanium system disconnect assembly with an 
Inconel system

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disconnect assembly in accordance with Part 4 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 777-54A0024, Revision 
1, dated November 4, 2010, terminates the actions required by this 
AD.

Credit for Actions Accomplished in Accordance With Previous Service 
Information

    (j) Actions accomplished before the effective date of this AD 
according to Boeing Alert Service Bulletin 777-54A0024, dated April 
1, 2010, are considered acceptable for compliance with the 
corresponding actions specified in this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. Send information to 
ATTN: Kevin Nguyen, Propulsion Branch, ANM-140S, FAA, Seattle 
Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 917-6501; fax (425) 917-6590. 
Information may be e-mailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

    Issued in Renton, Washington, on January 12, 2011.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-1119 Filed 1-19-11; 8:45 am]
BILLING CODE 4910-13-P


