

[Federal Register: September 7, 2007 (Volume 72, Number 173)]
[Proposed Rules]               
[Page 51388-51391]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07se07-24]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28413; Directorate Identifier 2007-NE-25-AD]
RIN 2120-AA64

 
Airworthiness Directives; General Electric Company (GE) CF6-80C2 
and CF6-80E1 Series Turbofan Engines

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 GE CF6-80C2 and CF6-80E1 series turbofan engines with fuel manifold 
part numbers (P/Ns) 1303M31G12 and 1303M32G12 installed. This proposed 
AD would require removing and discarding the loop clamps that assemble 
the fuel manifold to the compressor rear frame (CRF) friction damper 
brackets, visually inspecting the fuel manifold for wear at each clamp 
location, and replacing the clamps with new, zero-time parts. This 
proposed AD results from fuel manifold vibration during engine 
operation that causes the loop clamps that assemble the manifold to the 
CRF to deteriorate. Fourteen fuel leak events occurred over the past 
several years. We are proposing this AD to prevent fuel leaks during 
engine operation that could result in an under-cowl fire.

DATES: We must receive any comments on this proposed AD by November 6, 
2007.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 

the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to http://www.regulations.gov
 and follow the instructions for sending your 

comments electronically.
     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: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    You may examine the comments on this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov., or in Room W12-140 on the 

ground floor of the West Building, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA

[[Page 51389]]

01803; telephone (781) 238-7754; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2007-28413; 
Directorate Identifier 2007-NE-25-AD'' in the subject line 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 the 
DOT 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 the 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 AD Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov
; or in person at the Docket Operations office 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 Operations office (telephone (800) 647-5527) is the same as the 
Mail address provided in the ADDRESSES section. Comments will be 
available in the AD docket shortly after receipt.

Discussion

    During a pre-flight inspection in November 2002, a manifold fuel 
leak was found on a CF6-80C2B1F turbofan engine. This fuel leak 
resulted from fuel manifold vibration during engine operation, which 
caused the loop clamps that assemble the manifold to the CRF to 
deteriorate. The cushion on the loop clamp wore away resulting in the 
metal strip of the clamp rubbing into the fuel manifold. A fuel leak 
resulted. The high surface temperature of the CRF during engine 
operation could have ignited the leaking fuel resulting in an under-
cowl fire.
    In 2003, GE issued service bulletins for the CF6-80C2 and CF6-
80E1series turbofan engines recommending repetitive visual inspection 
of the fuel manifolds at intervals of 4,500 flight-hours (FH). Despite 
these recommendations, five fuel leak events occurred in 2006; one 
resulting in an under-cowl fire on a CF6-80C2B6F turbofan engine. There 
have been three additional fuel leak events to date in 2007. A total of 
thirteen CF6-80C2 series turbofan engine fuel leaks (November 2002 
through May 2007) and one CF6-80E1 fuel leak (January 2007) have been 
reported. Five of the recent events occurred within the 4,500 FH since 
the last inspection.
    Because of the increased number of fuel leak events and the low FH 
intervals since the last inspection, this proposed AD would reduce the 
initial re-inspection FH interval, and would require replacing the fuel 
manifold loop clamps with new, zero-time parts at each inspection. This 
proposed AD is necessary to prevent fuel leaks during engine operation 
that could result in an under-cowl fire.

Differences Between the Proposed AD and the Manufacturer's Service 
Information

    In the manufacturer's original service bulletins, GE recommends 
inspecting the fuel manifold for wear at 4,500 FH. However, the service 
bulletins do not recommend replacing the loop clamps at each 
inspection.
    Because recent field events involving fuel leaks indicate a reduced 
inspection interval is required, this AD would require removing loop 
clamps and inspecting the fuel manifold according to the following 
schedule:
     For engines previously inspected using GEAE service 
bulletins, SB 73-0226, dated March 5, 2003, for CF6-80C2 engines; or SB 
73-0061, dated April 14, 2003, for CF6-80E1 engines, within 1,750 FH 
since-last-inspection.
     If used loop clamps or clamps of unknown heritage were 
installed at last shop visit, within 1,750 FH since-last-shop-visit.
     For first-run engines and engines with zero-time, new loop 
clamps installed at last shop visit, within 7,500 FH.
     For affected engines that have already exceeded the 1,750 
FH initial inspection threshold, within 4,500 FH of the last inspection 
or 4 months after the effective date of the AD, whichever comes first.

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 products 
of this same type design. We are proposing this AD, which would require 
removing and discarding the loop clamps that assemble the fuel manifold 
to the compressor rear frame damper (CRF) friction damper brackets, 
visually inspecting the fuel manifold for wear at each loop clamp 
location, and replacing the clamps with new, zero-time parts.

Costs of Compliance

    We estimate that this proposed AD would affect 350 CF6-80C2 series 
turbofan engines installed on airplanes of U.S. registry. We also 
estimate that it would take about 4 work-hours per engine to perform 
the proposed actions, and that the average labor rate is $80 per work-
hour. Required parts would cost about $162 per engine. Based on these 
figures, we estimate the total cost of the proposed AD to U.S. 
operators for one manifold visual inspection and loop clamp replacement 
to be $168,700.

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 AD:

[[Page 51390]]

    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. Would 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. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration 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 
airworthiness directive:

General Electric Company: Docket No. FAA-2007-28413; Directorate 
Identifier 2007-NE-25-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by November 6, 
2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to:
    (1) GE CF6-80C2A1, -80C2A2, -80C2A3, -80C2A5, -80C2A8, -80C2A5F, 
-80C2B1, -80C2B2, -80C2B4, -80C2B6, -80C2B1F, -80C2B1F1, -80C2B1F2, 
-80C2B2F, -80C2B3F, -80C2B4F, -80C2B5F, -80C2B6F, -80C2B6FA, -
80C2B7F, -80C2B8F, -80C2D1F, -80C2L1F, -80C2K1F turbofan engine 
models configured with fuel manifold part numbers (P/Ns) 1303M31G12 
and 1303M32G12. These engines are installed on, but not limited to 
Boeing 747, 767, MD11, and Airbus A300 and A310 airplanes.
    (2) This AD also applies to GE CF6-80E1A1, -80E1A2, -80E1A3, -
80E1A4, -80E1A4/B turbofan engine models with fuel manifold P/N's 
1303M31G12 and 1303M32G12. These engines are installed on Airbus 
A330 airplanes.

Unsafe Condition

    (d) This AD results from fuel manifold vibration during engine 
operation that causes the clamps that assemble the manifold to the 
compressor rear frame (CRF) to deteriorate. We are issuing this AD 
to prevent fuel leaks. The high surface temperature of the CRF could 
ignite the leaking fuel resulting in an under-cowl fire.

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.

Removal and Replacement of Loop Clamps and Fuel Manifold Inspection 
Compliance Times

    (f) Remove and discard the loop clamps, P/N J1220G10, that 
assemble the fuel manifold to the Compressor Rear Frame friction 
damper brackets, inspect the fuel manifold for wear at each clamp 
location as specified in paragraph (g) of this AD, and replace the 
loop clamps with new, zero-time parts at each inspection. Use the 
following schedule in Table 1 of this AD:

          Table 1.--Inspection Schedule for Initial Inspections
------------------------------------------------------------------------
                                         Then replace clamps and inspect
                  If:                                within:
------------------------------------------------------------------------
(1) The engine was previously inspected  1,750 flight hours (FH) time-
 using GEAE service bulletins, SB 73-     since-last-inspection (TSLI).
 0226, dated March 5, 2003, for CF6-
 80C2 engines; or SB 73-0061, dated
 April 14, 2003, for CF6-80E1 engines.
(2) Used loop clamps or clamps of        1,750 FH time-since-last-shop-
 unknown heritage were installed at       visit.
 last shop visit.
(3) The engine is a first-run engine or  7,500 FH since zero-time, new
 is an engine with zero-time, new loop    loop clamps were installed.
 clamps previously installed.
(4) The engine has already exceeded the  4,500 FH TSLI, or 4 months
 1,750 FH initial inspection threshold.   after the effective date of
                                          this AD, whichever occurs
                                          first.
------------------------------------------------------------------------

Inspection of Fuel Manifold P/Ns 1303M31G12 and 1303M32G12

    (g) Remove any tape applied to clamp locations. Visually inspect 
the full circumference of the manifold at each clamp location.
    (h) If the fuel manifold shows any signs of wear, determine the 
depth of the wear as follows:
    (1) Measure the outside diameter of the tube using a pinpoint 
micrometer adjacent to the worn area.
    (2) Measure the worn area at the smallest diameter.
    (3) Subtract the measurement of the worn tube diameter from the 
unworn diameter measurement. Allowable wear is 0.0035 inch.
    (i) Before further flight, replace fuel manifolds with wear 
greater than 0.010 inch.
    (ii) Replace fuel manifolds with wear greater than 0.0035 inch, 
but less than 0.010 inch, within 50 flight cycles.

Revise Air Carrier's Continuous Airworthiness Maintenance Program 
(CAMP) and Airworthiness Limitation Section (ALS)

    (i) Within 30 days of the effective date of this AD, revise the 
air carrier's approved CAMP and ALS of Chapter 5 in the CF6-80C2 and 
CF6-80E1 Instructions for Continued Airworthiness to add:
    (1) Repetitive inspections of fuel manifolds, P/Ns 1303M31G12 
and 1303M32G12, as detailed in paragraphs (g) and (h) of this AD, at 
7,500 FH intervals.
    (2) Mandatory removal of loop clamps, P/N J1220G10, that 
assemble the fuel manifold, P/Ns 1303M31G12 and 1303M32G12, to the 
Compressor Rear Frame friction damper brackets, at each inspection.
    (3) Replacement of loop clamps, P/N J1220G10, with new, zero-
time parts, at each inspection.

Alternative Methods of Compliance

    (j) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (k) GE service bulletins GEAE CF6-80C2 S/B 73-0226, dated March 
5, 2003, and GEAE CF6-80E1 S/B 73-0061, dated April 14, 2003; and 
the following General Electric engine manuals pertain to the subject 
of this AD: CF6-80C2 Engine Manual GEK 92451; CF6-80C2L1F Engine 
Manual GEK 112213; CF6-80C2K1F Engine Manual GEK 112721; and CF6-
80E1 Engine Manual GEK 99376.
    (l) Contact Robert Green, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA, 01803; e-mail: 
robert.green@faa.gov; telephone (781) 238-7754; fax (781) 238-7199, 

for more information about this AD.


[[Page 51391]]


    Issued in Burlington, Massachusetts, on August 30, 2007.
Thomas A. Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E7-17682 Filed 9-6-07; 8:45 am]

BILLING CODE 4910-13-P
