[Federal Register Volume 60, Number 71 (Thursday, April 13, 1995)]
[Rules and Regulations]
[Pages 18729-18731]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-9133]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 90-ANE-25; Amendment 39-9186; AD 91-10-03 R1]


Airworthiness Directives; General Electric Company (GE) CF6-45 
and CF6-50 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment revises an existing airworthiness directive 
(AD), applicable to General Electric Company (GE) CF6-45 and CF6-50 
series turbofan engines, that currently requires repetitive inspections 
of high pressure compressor (HPC) rear shafts, and also requires 
installation of a certain rear shaft flange bolt configuration . This 
amendment clarifies that engines with a Parts Manufacturer Approval 
(PMA) bolt part number (P/N) installed must accomplish the inspection 
requirements of the AD, and allow the installation of the PMA bolt in 
lieu of the GE bolt. This amendment is prompted by the omission of the 
PMA bolt P/N from the current AD requirements. The actions specified by 
this AD are intended to prevent an HPC rear shaft fracture, which could 
result in an inflight engine shutdown and an uncontained engine 
failure.

DATES: Effective April 28, 1995.
    The incorporation by reference of certain publications listed in 
the regulations was approved by the Director of the Federal Register as 
of June 17, 1991.
    Comments for inclusion in the Rules Docket must be received on or 
before June 12, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 90-ANE-25, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    The service information referenced in this AD may be obtained from 
General Electric Company, Technical Publications Department, 1 Neumann 
Way, Cincinnati, OH 45215. This information may be examined at the FAA, 
New England Region, Office of the Assistant Chief 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: Robert Ganley, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7138, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: On March 18, 1991, the Federal Aviation 
Administration (FAA) issued AD 91-10-03, Amendment 39-6956 (56 FR 
19920, May 1, 1991), applicable to General Electric Company (GE) CF6-45 
and CF6-50 series turbofan engines, to require repetitive inspections 
of high pressure compressor (HPC) rear shafts, and installation of a 
certain rear shaft flange bolt configuration. That action was prompted 
by reports of 35 HPC rear shafts found cracked in the bolt hole area. 
That condition, if not corrected, could result in an HPC rear shaft 
fracture, which could result in an inflight engine shutdown and an 
uncontained engine failure.
    Since the issuance of that AD, the FAA has determined that Parts 
Manufacturer Approval (PMA) Production Approval Listing, Supplement No. 
27, authorizes the use of Valley-Todeco (VT) bolt, Part Number (P/N) 
VCD0016, in lieu of GE bolt, P/N 1375M69P01. Since VT bolt, P/N 
VCD0016, and GE bolt, P/N 1375M69P01, are identical in design, 
paragraphs (a)(1)(v), (a)(2), and (a)(2)(v) of AD 91-10-03 should also 
apply to HPC rear shafts that are installed with VT bolt, P/N VCD0016.
    The FAA has reviewed and approved the technical contents of GE 
Service Bulletin (SB) No. 72-958, Revision 1, dated October 18, 1990, 
that describes 

[[Page 18730]]
procedures for inspection of HPC rear shafts.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of this same type design, this AD 
revises AD 91-10-03 to continue the inspection requirements of the 
current AD, but adds HPC rear shafts that are installed with VT bolt, 
P/N VCD0016, to paragraphs (a)(1)(v), (a)(2), and (a)(2)(v). The 
actions are required to be accomplished in accordance with the service 
bulletin 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 90-ANE-25.'' 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. 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 removing Amendment 39-6956 (56 FR 
19920, May 1, 1991) and by adding a new airworthiness directive, 
Amendment 39-9186, to read as follows:

91-10-03 R1  General Electric Company: Amendment 39-9186. Docket 90-
ANE-25. Revises AD 91-10-03, Amendment 39-6956.

    Applicability: General Electric Company (GE) CF6-45 and CF6-50 
series turbofan engines installed on, but not limited to, McDonnell 
Douglas DC-10 series, Boeing 747 series, and Airbus A300 series 
aircraft.

    Note: This 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 use the authority provided in paragraph (e) to 
request approval from the FAA. This approval may address either no 
action, if the current configuration eliminates the unsafe 
condition, or different actions necessary to address the unsafe 
condition described in this AD. Such a request should include an 
assessment of the effect of the changed configuration on the unsafe 
condition addressed by this AD. In no case does the presence of any 
modification, alteration, or repair remove any engine from the 
applicability of this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent a high pressure compressor (HPC) rear shaft fracture, 
which could result in an inflight engine shutdown and an uncontained 
engine failure, accomplish the following:
    (a) Fluorescent penetrant inspect HPC rear shafts, Part Numbers 
(P/N) 9127M58P03, 9079M63P12, 9079M63P15, 9079M63P16, 9079M63P17, 
9079M63P18, and 9079M63P19, in accordance with the Accomplishment 
Instructions of GE Service Bulletin (SB) No. 72-958, Revision 1, 
dated October 18, 1990, as follows:
    (1) For HPC rear shafts currently installed with hook bolts, P/N 
9012M99G10, 9114M95G07, and 9114M95G10, inspect in accordance with 
the following schedule:
    (i) For shafts which have not been previously inspected and have 
10,000 cycles since new (CSN) or greater on the effective date of 
this airworthiness directive (AD), inspect within the next 1,500 
cycles in service (CIS) after the effective date of this AD.
    (ii) For shafts which have not been previously inspected and 
have less than 10,000 CSN on the effective date of this AD, inspect 
within the next 2,500 CIS from the effective date of this AD, or 
before accumulating 7,500 CSN, whichever occurs later. However, no 
shaft may exceed 11,500 CSN prior to inspection.
    (iii) For shafts that have been previously inspected and have 
3,000 cycles since last inspection (CSLI) or less on the effective 
date of this AD, reinspect within 4,500 CSLI, or before accumulating 
7,500 CSN, whichever occurs later.
    (iv) For shafts that have been previously inspected and have 
greater than 3,000 CSLI on the effective date of this AD, reinspect 
within the next 1,500 CIS from the effective date of this AD, or 
before accumulating 7,500 CSN, whichever occurs later.
    (v) Remove from service, HPC rear shaft hook bolts identified in 
(a)(1) of this AD, after any inspection performed in accordance with 
paragraph (a)(1) of this AD, and replace with new tapered turn-
around bolts, P/N 1375M69P01 or VCD0016.
    (2) For HPC rear shafts installed with turn-around bolts, P/N 
9249M54P01, or tapered turn-around bolts, P/N 1375M69P01 or 

[[Page 18731]]
VCD0016, inspect in accordance with the following schedule:
    (i) For shafts which have not been previously inspected and have 
6,500 CSN or greater on the effective date of this AD, inspect 
within the next 2,500 CIS after the effective date of this AD.
    (ii) For shafts which have not been previously inspected and 
have less than 6,500 CSN on the effective date of this AD, inspect 
prior to accumulating 9,000 CSN.
    (iii) For shafts that have been previously inspected and have 
3,500 CSLI or less on the effective date of this AD, reinspect 
within 6,000 CSLI, or before accumulating 9,000 CSN, whichever 
occurs later.
    (iv) For shafts that have been previously inspected and have 
greater than 3,500 CSLI on the effective date of this AD, reinspect 
within the next 2,500 CIS from the effective date of this AD, or 
before accumulating 9,000 CSN, whichever occurs later.
    (v) Remove from service, HPC rear shaft turn-around bolts 
identified in paragraph (a)(2) of this AD, after any inspection 
performed in accordance with paragraph (a)(2) of this AD, and 
replace with new tapered turn-around bolts, P/N 1375M69P01 or 
VCD0016.

    Note: Information concerning the tapered turn-around bolt noted 
in paragraph (a) of this AD can be found in GE SB No. 72-877.

    (b) Remove from service, prior to further flight, any shafts 
found cracked at inspection.
    (c) Thereafter, for shafts which have been inspected in 
accordance with paragraph (a) of this AD, reinspect in accordance 
with the Accomplishment Instructions of GE SB No. 72-958, Revision 
1, dated October 18, 1990, at intervals not to exceed 6,000 CSLI.
    (d) Compliance with paragraph (a) of AD 91-10-03 satisfies the 
corresponding requirements of paragraph (a) of this AD.
    (e) An alternative method of compliance or adjustment of the 
initial 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 AD, if any, may be 
obtained from the Engine Certification Office.

    (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 requirements of this AD can be accomplished.
    (g) The actions required by this AD shall be done in accordance 
with the following service document:

------------------------------------------------------------------------
        Document No.          Pages     Revision            Date        
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GE SB No. 72-958...........      1-2  1...........  Oct. 18, 1990.      
                                 3-6  Original....  Aug. 15, 1990.      
  Total pages: 6.                                                       
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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 as of June 17, 1991. Copies may be obtained from General Electric 
Company, Technical Publications Department, 1 Neumann Way, 
Cincinnati, OH 45215. Copies may be inspected at the FAA, New 
England Region, Office of the Assistant Chief 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.
    (h) This amendment becomes effective on April 28, 1995.

    Issued in Burlington, Massachusetts, on April 4, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-9133 Filed 4-11-95; 11:45 am]
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