[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
