AD 2000-12-08

[Federal Register Volume 65, Number 124 (Tuesday, June 27, 2000)]
[Rules and Regulations]
[Pages 39536-39538]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-16200]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NE-45-AD; Amendment 39-11786; AD 2000-12-08]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Models CF6-
80C2A1/A2/A3/A5/A5F/A8/D1F Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to General Electric Company (GE) Models CF6-80C2A1/A2/A3/
A5/A5F/A8/D1F turbofan engines. This AD requires initial and repetitive 
visual inspections of left hand and right hand aft engine mount link 
assemblies for separations, cracks and spherical bearing race 
migration. Cracked or separated parts must be replaced prior to further 
flight. If spherical bearing race migration is discovered, an 
additional borescope inspection for cracks is also required. If no 
cracks are discovered by the additional borescope inspection, 
assemblies have a 75-cycle grace period for remaining in service before 
replacement. Finally, installation of improved aft engine mount link 
assemblies constitutes terminating action to the inspections of this 
AD. This amendment is prompted by a report of a fractured left hand aft 
engine mount link discovered during a scheduled removal of an engine of 
similar design. The actions specified by the AD are intended to prevent 
aft engine mount link failure, which can result in adverse 
redistribution of the aft engine mount loads and possible aft engine 
mount system failure.

DATES: Effective date August 28, 2000. The incorporation by reference 
of certain publications listed in the rule is

[[Page 39537]]

approved by the Director of the Federal Register as of August 28, 2000.

ADDRESSES: The service information referenced in this AD may be 
obtained from General Electric Company via Lockheed Martin Technology 
Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, 
telephone (513) 672-8400, fax (513) 672-8422. 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: Karen Curtis, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7192, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to General Electric Company Models 
CF6-80C2A1/A2/A3/A5/A5F/A8/D1F turbofan engines was published in the 
Federal Register on February 23, 2000 (65 FR 8892). That action 
proposed to require initial and repetitive visual inspections of left 
hand and right hand aft engine mount link assemblies for separations, 
cracks and spherical bearing race migration and replacement of cracked 
or separated parts prior to further flight.

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Link Assembly Replacement Cost

    Although one comment agrees with the technical content of the AD, 
concern was expressed because the economic analysis within the NPRM 
indicates that the cost to replace link assemblies is approximately 
$7,000 per engine, while the service bulletin indicates the cost is 
$9,718 per engine. The comment suggests that the FAA should change its 
economic analysis to match the cost quoted in the Service Bulletin. The 
FAA does not agree. The FAA started with the new part costs cited in 
the service bulletin, but took into account that some useful life had 
been realized from the existing parts. The $7,000 per engine cost to 
replace link assemblies quoted in the NPRM represents the cost of the 
lost life of existing, installed links.

Length of Grace Period

    Another comment requests that the length of the grace period 
permitted to remove migrated links that are not cracked, be tied to the 
extent of bearing migration. The FAA does not agree. Bearing migration 
results from a failed or undersized bearing race swage lip. There is no 
data available to quantify the rate of migration once the retention 
feature is overcome. Once migration begins, there is no data to 
indicate that it will not progress until contact is made with the boss 
of the turbine rear frame clevis. Therefore, the analysis assumed the 
worst case condition (i.e. maximum migration) for calculating the 
reduction in useful life. The 75-cycle allowance for replacement of 
migrated, but not cracked links, is considered conservative, but 
reasonable.

Replacement of Aft Engine Mount Link Assemblies

    One comment requests that the FAA change the requirement to replace 
aft engine mount link assemblies with improved aft engine mount link 
assemblies by deleting the requirement that link assemblies be replaced 
prior to the engine accumulating 29,000 cycles since new. The comment 
stated that link assemblies are sometimes installed new on engines that 
have already accumulated a considerable number of cycles and that the 
link assemblies are inspected themselves. Therefore, replacement of 
link assemblies should not be tied to engine cycles. The FAA does not 
agree. Links are expected to be replaced ``at the next engine shop 
visit.'' However, since the current link assemblies are not life-
limited and not routinely tracked, the 29,000 cycles since new (CSN) 
limit was added as an absolute limit. Operators may apply for an 
Alternate Method of Compliance (AMOC) for link assemblies installed on 
engines that will exceed the 29,000 CSN limit prior to their next 
scheduled engine shop visit provided sufficient records of link 
assembly CSN data are available to show that the links will not exceed 
29,000 CSN.

Conclusion

    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.

Economic Analysis

    There are approximately 975 engines of the affected design in the 
worldwide fleet. The FAA estimates that 323 engines installed on 
aircraft of US registry will be affected by this AD. The cost to 
replace link assemblies is approximately $7,000. The FAA estimates that 
it will take approximately 0.5 work hours per engine to accomplish each 
of an average of two interim inspections prior to next engine shop 
visit and that the average labor rate is $60 per work hour. Based on 
these figures, the total cost impact of the AD on US operators is 
estimated to be $2,280,380.

Regulatory Impact

    The regulations adopted herein will 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under 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. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it 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:

2000-12-08   General Electric Company: Amendment 39-11786. Docket 
99-NE-45-AD.
    Applicability: General Electric Company (GE) Models CF6-80C2A1/
A2/A3/A5/A5F/

[[Page 39538]]

A8/D1F turbofan engines, with left hand aft engine mount link 
assemblies, part numbers (P/Ns) 9348M79G01 or 9348M79G02 installed, 
or right hand aft engine mount link assemblies, P/Ns 9348M84G01 or 
9348M84G02 installed. These engines are installed on but not limited 
to Airbus Industrie A300 and A310 series, and McDonnell Douglas MD-
11 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 (e) 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 aft engine mount link failure, which can result in 
adverse redistribution of the aft engine mount loads and possible 
aft engine mount system failure, accomplish the following:

Initial Inspection

    (a) Visually inspect aft engine mount link assemblies for 
separations, cracks, and spherical bearing race migration. as 
follows:

Not Previously Inspected

    (1) Within 400 cycles-in-service (CIS) after the effective date 
of this AD, if not previously inspected using GE CF6-80C2 Alert 
Service Bulletin (ASB) 72-A0964, Revision 2, dated January 24, 2000, 
Revision 1, dated November 12, 1999, or Original, dated April 16, 
1999, OR

Previously Inspected

    (2) Within 400 cycles-since-last-inspection (CSLI), if 
previously inspected using GE CF6-80C2 Alert Service Bulletin (ASB) 
72-A0964, Revision 2, dated January 24, 2000, Revision 1, dated 
November 12, 1999, or Original, dated April 16, 1999,
    (3) Inspect in accordance with the Accomplishment Instructions 
of GE CF6-80C2 ASB 72-A0964, Revision 2, dated January 24, 2000.

Cracked or Separated Parts

    (4) If a crack or separation is discovered, prior to further 
flight:
    (i) Remove the cracked or separated aft engine mount link 
assembly and the attaching hardware from service; AND
    (ii) Replace with serviceable parts.

Removal of Aft Engine Mount Link Assemblies with Spherical Bearing Race 
Migration

    (5) If an aft engine mount link assembly is found with spherical 
bearing race migration, but no cracks or separations, prior to 
further flight, EITHER:
    (i) Remove the aft engine mount link assembly and the attaching 
hardware from service and replace with serviceable parts; OR

Additional Borescope Inspection of Aft Engine Mount Link Assemblies 
with Spherical Bearing Race Migration

    (ii) Perform an additional borescope inspection for cracks in 
accordance with paragraph (3)(I) of the Accomplishment Instructions 
of GE CF6-80C2 ASB 72-A0964, Revision 2, dated January 24, 2000.

After Additional Borescope Inspection, If Parts Are Cracked

    (6) If a crack indication is discovered, prior to further 
flight, remove the cracked aft engine mount link assembly and the 
attaching hardware from service, and replace with serviceable parts.

After Additional Borescope Inspection, If Parts Are Not Cracked (Grace 
Period)

    (7) If crack indications are not discovered, within 75 CIS after 
the inspection performed in accordance with paragraph (a)(5)(ii) of 
this AD, remove the aft engine mount link assembly from service, and 
replace with serviceable parts.

Attaching Hardware

    (8) Attaching hardware may be returned to service after 
inspection in accordance with paragraph 3(I)(1)(d) or 3(I)(2)(d) of 
GE CF6-80C2 ASB 72-A0964, Revision 2, dated January 24, 2000, as 
applicable, only if visual inspection of the removed link shows no 
cracks or separations.

    Note 2: Link attaching hardware includes the nuts, bolts and 
washers that secure the link.

Repetitive Inspections

    (b) Thereafter, perform the actions required by paragraph (a) 
and associated subparagraphs at intervals not to exceed 400 CSLI.

Replacement with Improved Link Assemblies

    (c) Replace aft engine mount link assemblies with improved aft 
engine mount link assemblies at the next engine shop visit (ESV), or 
before accumulating 29,000 engine cycles since new (CSN), whichever 
occurs first.
    (1) Replace in accordance with the Accomplishment Instructions 
of CF6-80C2 ASB 72-A0989, dated January 19, 2000.

Left Hand Aft Engine Mount Link Assemblies

    (2) Replace left-hand aft engine mount link assemblies, P/Ns 
9348M79G01 or 9348M79G02, with improved left-hand aft engine mount 
link assemblies, P/N 1846M23G01.

Right Hand Aft Engine Mount Link Assemblies

    (3) Replace right hand aft engine mount link assemblies, P/Ns 
9348M84G01 or 9348M84G02, with improved right hand aft engine mount 
link assemblies, P/N 9348M84G03.

Terminating Action

    (d) Installation of improved aft engine mount link assemblies in 
accordance with paragraph (c) and its subparagraphs constitutes 
terminating action to the inspections required by paragraphs (a) and 
(b) of this AD.

Alternative Methods of Compliance

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

Ferry Flights

    (f) 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 inspection requirements of this AD can be accomplished.

Incorporation By Reference

    (g) The inspection shall be done in accordance with the 
following GE Alert Service Bulletins: (ASBs) CF6-80C2 72-A0964, 
Revision 2, dated January 24, 2000; Revision 1, dated November 12, 
1999; Original, dated April 16, 1999 and CF6-80C2 72-A0989, dated 
January 19, 2000. 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 General 
Electric Company via Lockheed Martin Technology Services, 10525 
Chester Road, Suite C, Cincinnati, Ohio 45215, telephone (513) 672-
8400, fax (513) 672-8422. 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.

Effective Date

    (h) This amendment becomes effective on August 28, 2000.

    Issued in Burlington, Massachusetts, on June 8, 2000.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-16200 Filed 6-26-00; 8:45 am]
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