Airworthiness Directives; General Electric Company CF6-80A3 Series Turbofan Engines

[Federal Register Volume 63, Number 141 (Thursday, July 23, 1998)]
[Rules and Regulations]
[Pages 39489-39491]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-19485]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-35-AD; Amendment 39-10668; AD 98-15-17]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF6-80A3 
Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to General Electric Company CF6-80A3 series turbofan 
engines. This action requires initial and repetitive on-wing borescope 
inspections of the left hand aft mount link assembly for cracks, 
bearing migration, and bearing race rotation, and, if necessary, 
replacement with serviceable parts. This amendment is prompted by a 
report of a fractured left hand aft mount link discovered during a 
scheduled engine removal. The actions specified in this AD are intended 
to prevent left hand aft mount link failure, which can result in 
adverse redistribution of the aft mount loads and possible aft mount 
system failure.

DATES: Effective August 7, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 7, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before September 21, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 98-ANE-35-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``9-ad-
[email protected]''. Comments sent via the Internet must contain 
the docket number in the subject line.
    The service information referenced in this AD may be obtained from 
Rohr, Inc., 850 Lagoon Dr., Chula Vista, CA 91910-2098; telephone (619-
691-3102), fax (619-498-7215). This information may be examined at the 
FAA, New England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: William S. Ricci, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7742, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA) 
has received a report of a fractured left hand aft mount link 
discovered during a scheduled engine removal of a General Electric 
Company (GE) CF6-80A3 series turbofan engine. Failure analysis revealed 
a fatigue type fracture with no metallurgical anomalies and no 
geometric discrepancies in the area of the crack origin. Over the 
course of the investigation of the cracked left hand aft mount link 
assembly and the review of other link assemblies returned from service, 
two conditions were noted that individually could be considered benign 
but when combined could result in higher stress levels and the reduced 
fatigue capability of link assemblies. The first condition is the 
incorrect orientation of the entry slots of the spherical bearing 
assembly and the second condition is high friction between the bearing 
and the race resulting from contamination between faying bearing 
surfaces. This condition, if not corrected, could result in left hand 
aft mount link failure, which can result in adverse redistribution of 
the aft mount loads and possible aft mount system failure.
    On May 20, 1998, the Direction Generale de L'Aviation Civile 
(DGAC), the airworthiness authority of France, issued AD 98-205-260(B), 
applicable to Airbus A310 aircraft, addressing this unsafe condition by 
requiring initial and repetitive on-wing borescope inspections of the 
left hand aft mount link assembly for cracks, bearing

[[Page 39490]]

migration, and bearing race rotation, and, if necessary, replacement 
with serviceable parts. On June 3, 1998, the Transport Airplane 
Directorate (TAD) of the FAA issued AD 98-12-24, also applicable to 
Airbus A310 aircraft, requiring a one-time on-wing borescope inspection 
for cracks and bearing migration. The Engine and Propeller Directorate 
has consulted with the DGAC and the TAD and has determined that it is 
necessary to issue this AD applicable to GE CF6-80A3 series engines 
mandating repetitive borescope inspections in order to assure the 
continued airworthiness of the aft mount links.
    The FAA has reviewed and approved the technical contents of Rohr 
Alert Service Bulletin (ASB) No. CF6-80A3-NAC-A71-060, dated January 
30, 1998, that describes procedures for borescope inspections of the 
left hand aft mount link for cracks, bearing migration, and bearing 
race rotation.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design, this AD is 
being issued to prevent left hand aft mount link failure. This AD 
requires initial and repetitive on-wing borescope inspections of the 
left hand aft mount link assembly for cracks, bearing migration, and 
bearing race rotation, and, if necessary, replacement with serviceable 
parts. The investigation is ongoing, and further rulemaking may be 
necessary that may require additional piece-part inspections or the 
installation of a modified left hand aft mount link assembly that would 
terminate the repetitive inspections required by this AD. The actions 
are required to be accomplished in accordance with the ASB described 
previously.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD 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 98-ANE-35-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, may 
be obtained from the Rules Docket at the location provided under the 
caption ADDRESSES.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

98-15-17  General Electric Company: Amendment 39-10668. Docket 98-
ANE-35-AD.

    Applicability: General Electric Company (GE) CF6-80A3 series 
turbofan engines, installed on but not limited to Airbus A310 series 
aircraft.

    Note 1: This airworthiness directive (AD) applies to each engine 
identified in the preceding applicability provision, regardless of 
whether it has been modified, altered, or repaired in the area 
subject to the requirements of this AD. For engines that have been 
modified, altered, or repaired so that the performance of the 
requirements of this AD is affected, the owner/operator must request 
approval for an alternative method of compliance in accordance with 
paragraph (b) of this AD. The request should include an assessment 
of the effect of the modification, alteration, or repair on the 
unsafe condition addressed by this AD; and, if the unsafe condition 
has not been eliminated, the request should include specific 
proposed actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent left hand aft mount link failure, accomplish the 
following:
    (a) Perform initial and repetitive borescope on-wing inspections 
of the left hand aft mount link assembly for cracks, bearing 
migration, and bearing race rotation exceeding the limits specified 
in Rohr Alert Service Bulletin (ASB) No. CF6-80A3-NAC-A71-060, dated 
January 30, 1998, and, if necessary, replace with serviceable parts, 
as follows:
    (1) Initially inspect within 50 cycles in service (CIS) after 
the effective date of this AD.
    (2) Thereafter, reinspect at intervals not to exceed 175 CIS 
since last inspection.
    (3) Prior to further flight, remove from service any left hand 
aft mount link discovered with cracks, bearing migration, or bearing 
race rotation, exceeding the limits specified in Rohr ASB No. CF6-
80A3-NAC-A71-060, dated January 30, 1998, and replace with 
serviceable parts.
    (b) 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

[[Page 39491]]

Certification Office. Operators shall submit their requests through 
an appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Engine Certification 
Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the aircraft to a location where 
the requirements of this AD can be accomplished.
    (d) The actions required by this AD shall be done in accordance 
with the following Rohr ASB:

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           Document No.             Pages               Date            
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CF6-80A3-NAC-A71-060.............    1-10  January 30, 1998.            
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    Total pages: 10.
    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from Rohr, Inc., 850 Lagoon Dr., 
Chula Vista, CA 91910-2098; telephone (619-691-3102), fax (619-498-
7215). Copies may be inspected at the FAA, New England Region, 
Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA; or at the Office of the Federal Register, 800 North 
Capitol Street, NW., suite 700, Washington, DC.
    (e) This amendment becomes effective on August 7, 1998.

    Issued in Burlington, Massachusetts, on July 15, 1998.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 98-19485 Filed 7-22-98; 8:45 am]
BILLING CODE 4910-13-U

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