[Federal Register Volume 63, Number 14 (Thursday, January 22, 1998)]
[Proposed Rules]
[Pages 3275-3276]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-1484]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-46-AD]
RIN 2120-AA64


Airworthiness Directives; CFM International CFM56-2, -2A, -2B, -
3, -3B, and -3C 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 CFM International (CFMI) CFM56-2, 
-2A, -2B, -3, -3B, and -3C series turbofan engines. This proposal would 
require a one-time eddy current inspection (ECI) for cracks or gouges 
in certain high pressure turbine rotor (HPTR) disks. This proposal is 
prompted by a report of a HPTR disk found to have a crack in a rim bolt 
hole during a routine shop manual ECI. The actions specified by the 
proposed AD are intended to prevent the potential for an uncontained 
failure of the HPTR disk, which could result in an inflight engine 
shutdown, aborted takeoff, or damage to the aircraft.

DATES: Comments must be received by March 23, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 97-ANE-46-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8:00 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 CFM International, Technical Publications Department, 1 
Neumann Way, Cincinnati, OH 45215; telephone (513) 552-2981, fax (513) 
552-2816. 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 (781) 238-7132; fax (781) 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 97-ANE-46-AD.'' 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. 97-ANE-46-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    This proposed airworthiness directive (AD) is applicable to CFM 
International (CFMI) CFM56-2, -2A, -2B, -3, -3B, and -3C series 
turbofan engines. The Federal Aviation Administration (FAA) received a 
report of a high pressure turbine rotor (HPTR) disk found to have a 
crack in a rim bolt hole during a routine shop manual eddy current 
inspection (ECI). Investigation revealed that the crack initiated from 
a gouge in the bolt hole. The gouge is the result of a drill break that 
occurred when the rim bolt hole was being manufactured. A review of 
manufacturing records indicates that a total of 276 HPTR disks have 
documented drill breaks that occurred during manufacture of the HPTR 
disk. This condition, if not corrected, could result in an uncontained 
failure of the HPTR disk, which could result in an inflight engine 
shutdown, aborted takeoff, or damage to the aircraft.
    The FAA has reviewed and approved the technical contents of CFM56-2 
Service Bulletin (SB) No. 72-817, dated January 14, 1997, CFM56-2A SB 
No. 72-419, Revision 1, dated January 31, 1997, CFM56-2B SB No. 72-561, 
Revision 1, dated January 31, 1997, and CFM56-3/-3B/-3C SB No. 72-843, 
dated January 14, 1997, that describe procedures for ECI for cracks or 
gouges in HPTR disks.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require a one-time ECI for cracks or gouges in 
certain HPTR disks. The calendar end-dates listed in the compliance 
section of this AD were based upon risk analysis. The actions would be 
required to be accomplished in accordance with the SBs described 
previously.
    There are approximately 276 engines of the affected design in the 
worldwide

[[Page 3276]]

fleet. The FAA estimates that 100 engines on aircraft of U.S. registry 
would be affected by the proposed AD, that it would take approximately 
300 work hours per engine to accomplish the proposed actions, and that 
the average labor rate is $60 per work hour. Replacement parts, if 
required, would cost approximately $86,000 per engine. Based on these 
figures, and assuming that 16 of the inspected HPTR disks will require 
replacement, the total cost impact of the proposed AD on U.S. operators 
is estimated to be $3,176,000. The manufacturer has advised the FAA 
that certain costs incurred from the inspection and replacement of 
parts affected by this AD may be borne by the manufacturer, therefore, 
the total cost impact of this AD to U.S. operators may be less than 
estimated by the FAA.
    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 
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), 40101, 40113, 44701.

Sec. 39.13  [Amended]

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

    CFM International: Docket No. 97-ANE-46-AD.

    Applicability: CFM International (CFMI) CFM56-2, -2A, -2B, -3, -
3B, and -3C series turbofan engines installed on, but not limited to 
McDonnell Douglas DC-8 series, Boeing 737 series, as well as Boeing 
E-3, E-6, and KC-135 (military) 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 (c) 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 the potential for an uncontained failure of the high 
pressure turbine rotor (HPTR) disk, which could result in an 
inflight engine shutdown, aborted takeoff, or damage to the 
aircraft, accomplish the following:
    (a) Eddy current inspect for cracks or gouges in HPTR disks, 
Part Numbers 1475M29P01, 1475M29P02, 9514M69P01, 9514M69P04, 
9514M69P05, 9514M69P06, and 9514M69P09, with Serial Numbers listed 
in Table 1 of the applicable Service Bulletin (SB), as follows:
    (1) For CFM56-2 engines, in accordance with CFM56-2 SB No. 72-
817, dated January 14, 1997, prior to June 30, 1998.
    (2) For CFM56-2A engines, in accordance with CFM56-2A SB No. 72-
419, Revision 1, dated January 31, 1997, within 500 cycles in 
service (CIS) after the effective date of this AD, or by December 
31, 1999, whichever occurs first.
    (3) For CFM56-2B engines, in accordance with CFM56-2B SB No. 72-
561, Revision 1, dated January 31, 1997, within 500 CIS after the 
effective date of this AD, or by December 31, 1999, whichever occurs 
first.
    (4) For CFM56-3, -3B, and -3C engines, in accordance with CFM56-
3/-3B/-3C SB No. 72-843, dated January 14, 1997, prior to June 30, 
1998.
    (b) Remove from service HPTR disks found cracked or gouged, and 
replace with serviceable parts.
    (c) 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 request 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.

    (d) 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.

    Issued in Burlington, Massachusetts, on January 8, 1998.
James C. Jones,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 98-1484 Filed 1-21-98; 8:45 am]
BILLING CODE 4910-13-U