[Federal Register Volume 59, Number 83 (Monday, May 2, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-10393]


[[Page Unknown]]

[Federal Register: May 2, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-02]

 

Airworthiness Directives; General Electric Company CF6-80C2 
Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to General Electric Company (GE) CF6-
80C2 series turbofan engines. This proposal would require a repetitive 
oil quantity check after engine start-up and prior to taxi, and 
installation of a flame arrestor plug support (FAPS) in the aft end of 
the center vent tube as a terminating action to the repetitive oil 
quantity checks. This proposal is prompted by three reports of 
uncontained engine failure due to separation of the fan mid shaft. The 
actions specified by the proposed AD are intended to prevent an 
uncontained engine failure and inflight engine shutdown due to fuel 
contamination of the oil system.

DATES: Comments must be received by June 1, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-02, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from General Electric Aircraft Engines, CF6 Distribution 
Clerk, room 132, 111 Merchant Street, Cincinnati, OH 45246. This 
information may be examined at the FAA, New England Region, Office of 
the Assistant Chief Counsel, 12 New England Executive Park, Burlington, 
MA.

FOR FURTHER INFORMATION CONTACT: Glorianne Messemer, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (617) 238-7132, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 94-ANE-02.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 94-ANE-02, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received three 
reports of uncontained engine failures due to separation of the fan mid 
shafts on General Electric Company (GE) CF6-80C2 series turbofan 
engines. Separation of the fan mid shaft results from sustained fires 
in the forward fan shaft cavity, due to fuel contamination of the oil 
system. The GE CF6-80C2 series engine has a lube system center vent 
design which releases air and oil vapor axially through the engine and 
into the centerbody cavity. The vapor then goes overboard through a 
hole in the aft centerbody exhaust plug. If fuel enters the engine oil 
system, fuel vapor passes through this center vent system. In the 
centerbody cavity, the center vent air is allowed to circulate and 
contact hot surfaces. These surfaces are hot enough to ignite heavily 
fuel-laden air. The pressure rise in the centerbody cavity from such an 
ignition results in backflow of the sump vent system, which can cause a 
flame to travel forward up the center vent tube (CVT). This may result 
in a sustained fire in the forward fan shaft cavity which can cause 
separation of the fan mid shaft. Installation of a flame arrestor plug 
support (FAPS) prevents the movement of a flame up the CVT, sustained 
burning in the forward fan shaft cavity, and subsequent fan mid shaft 
separations. Until such time as the FAPS is installed, operators must 
perform a repetitive oil quantity check for fuel contamination after 
engine start-up but prior to taxi. If the oil quantity indicates 5 
gallons (20 quarts) or more, operators must troubleshoot and flush the 
oil system prior to further flight in accordance with the applicable 
maintenance manual. This condition, if not corrected, could result in 
an uncontained engine failure and inflight engine shutdown due to fuel 
contamination of the oil system.
    The FAA has reviewed and approved the technical contents of GE CF6-
80C2 Service Bulletin (SB) No. 72-648, Revision 1, dated January 11, 
1993, and GE CF6-80C2 SB No. 72-095, Revision 2, dated January 11, 
1993. These SB's describe procedures for installation of the CVT FAPS.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed airworthiness directive (AD) would require a repetitive oil 
quantity check after engine start-up and prior to taxi, and 
installation of a FAPS in the aft end of the CVT as a terminating 
action to the repetitive oil quantity checks. The manufacturer has 
advised the FAA that they will have manufactured all the parts needed 
for the entire fleet by the compliance end-date of August 1, 1994. The 
FAA has determined that the problem of fuel contamination of the oil 
system is not dependent upon cyclic or hourly usage and therefore 
proposes a compliance end-date of August 1, 1994. The actions would be 
required to be accomplished in accordance with the service bulletins 
described previously.
    The FAA estimates that 1,570 engines installed on aircraft of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 8 work hours per engine to accomplish the proposed 
actions, and that the average labor rate is $55 per work hour. Required 
parts would cost approximately $2,316. Out of the 1,570 engines, the 
manufacturer has advised the FAA that 96 percent of the fleet have 
accomplished the requirements of this AD. Based on these figures, the 
total cost impact of the proposed AD on U.S. operators is estimated to 
be $173,077.
    The regulations proposed herein would not have substantial direct 
effects 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, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that 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) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 14 
CFR part 39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

    General Electric Company: Docket No. 94-ANE-02.

    Applicability: General Electric Company (GE) CF6-80C2 series 
turbofan engines installed on, but not limited to, Airbus A300 and 
A310 series, Boeing 747 and 767 series, and McDonnell Douglas MD-11 
series aircraft.

    Compliance: Required as indicated, unless accomplished 
previously.

    To prevent an uncontained engine failure and inflight engine 
shutdown due to fuel contamination of the oil system, accomplish the 
following:
    (a) Before each flight, perform an oil quantity inspection for 
fuel contamination at least 30 seconds after the engine reaches 
stabilized idle but prior to taxi. If the oil quantity indicates 5 
gallons (20 quarts) or more, maintenance investigation is required 
prior to takeoff.
    (b) If the oil quantity indicates 5 gallons (20 quarts) or more, 
flush and troubleshoot the oil system for fuel contamination prior 
to further flight.
    (c) For engines with No. 6 bearing plug, Part Number (P/N) 
1375M78G01, replace the No. 6 bearing plug with center vent tube 
(CVT) flame arrestor plug support (FAPS) in accordance with GE CF6-
80C2 Service Bulletin (SB) No. 72-648, Revision 1, dated January 11, 
1993, prior to August 1, 1994.
    (d) For engines with No. 6 bearing plug, P/N 9362M36G01, replace 
the fan mid shaft assembly, the mid fan duct assembly, and the 
retaining ring, in accordance with GE CF6-80C2 SB No. 72-095, 
Revision 2, dated January 11, 1993, and replace the No. 6 bearing 
plug with CVT FAPS in accordance with GE CF6-80C2 SB No. 72-648, 
Revision 1, dated January 11, 1993, prior to August 1, 1994.
    (e) Installation of the CVT FAPS in accordance with paragraphs 
(c) or (d) of this AD, constitutes terminating action for paragraphs 
(a) and (b) of this AD.
    (f) The oil quantity inspection required by paragraph (a) of 
this AD may be performed by the pilot. The checks must be recorded 
in accordance with Federal Aviation Regulation (FAR) section 43.9, 
and records maintained by the owner/operator as required by FAR 
section 121.380(a)(2)(v), or 91.417(a)(2)(v), as applicable.
    (g) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Engine Certification Office. The 
request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (h) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the aircraft to a location where the 
requirements of this AD can be accomplished.

    Issued in Burlington, Massachusetts, on April 13, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-10393 Filed 4-29-94; 8:45 am]
BILLING CODE 4910-13-P