[Federal Register Volume 63, Number 168 (Monday, August 31, 1998)]
[Proposed Rules]
[Pages 46202-46204]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-23361]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-61-AD]
RIN 2120-AA64
Airworthiness Directives; Pratt & Whitney PW2000 Series Turbofan
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This proposal would require revisions to the Time Limits
Section (TLS) of the manufacturer's Engine Manuals (EMs) for Pratt &
Whitney (PW) PW2000 series turbofan engines to include required
enhanced inspection of selected critical life-limited parts at each
piece-part exposure. This proposal would also require an air carrier's
approved continuous airworthiness maintenance program to incorporate
these inspection procedures. Air carriers with an approved continuous
airworthiness maintenance program would be allowed to either maintain
the records showing the current status of the inspections using the
record keeping system specified in the air carrier's maintenance
manual, or establish an acceptable alternate method of record keeping.
This proposal is prompted by an FAA study of in-service events
involving uncontained failures of critical rotating engine parts which
indicated the need for improved inspections. The improved inspections
are needed to identify those critical rotating parts with conditions,
that if allowed to continue in service, could result in uncontained
failures. The actions specified by this proposed AD are intended to
prevent critical life-limited rotating engine part failure, which could
result in an uncontained engine failure and damage to the airplane.
DATES: Comments must be received by November 30, 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-61-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be sent
via the Internet using the following address: ``engineprop@faa.dot.gov''. Comments sent via the Internet must contain
the docket number in the subject line. Comments may be inspected at
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday,
except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Peter White, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (781)
238-7128, 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 98-ANE-61-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 Regional Counsel,
Attention: Rules Docket No. 98-ANE-61-AD, 12 New England Executive
Park, Burlington, MA 01803-5299.
Discussion
A recent FAA study analyzing 15 years of accident data for
transport category airplanes identified several failure mode root
causes that can result in serious safety hazards to transport category
airplanes. This study identified uncontained failure of critical life-
limited rotating engine parts as the leading engine-related safety
hazard to airplanes. Uncontained engine failures have resulted from
undetected cracks in rotating parts that initiated and propagated to
failure. Cracks can originate from causes such as unintended excessive
stress from the original design, or they may initiate from stresses
induced from material flaws, handling damage, or damage from machining
operations. The failure of rotating parts can present a significant
safety hazard to the airplanes by release of high energy fragments that
could injure passengers or crew by penetration of the cabin, damage
flight control surfaces, sever flammable fluid lines, or otherwise
compromise the airworthiness of the airplane.
Accordingly, the FAA has developed an intervention strategy to
significantly reduce uncontained engine failures. This intervention
strategy was developed after consultation with industry and will be
used as a model for future initiatives. This intervention strategy is
to conduct enhanced, nondestructive inspections of fan hubs which could
most likely result in a safety hazard to the airplane in the event of a
disk failure. The need for additional rule making is also being
considered by the FAA. Future ADs may be issued introducing additional
intervention strategies to further reduce or eliminate uncontained
engine failures.
Properly focused enhanced inspections require identification of the
parts whose failure presents the highest safety hazard to the airplane,
identifying the most critical features to inspect on these parts, and
utilizing inspection procedures and techniques that improve crack
detection. The FAA, with close cooperation of the engine manufacturers,
has completed a detailed analysis that identifies the most safety
significant parts and features, and the most appropriate inspection
methods.
Critical life-limited high energy rotating parts are currently
subject to some form of recommended crack inspection when exposed
during engine maintenance or disassembly. As a result of this AD, the
inspections currently
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recommended by the manufacturer will become mandatory for those parts
listed in the compliance section. Furthermore, the FAA intends that
additional mandatory enhanced inspections resulting from this AD serve
as an adjunct to the existing inspections. The FAA has determined that
the enhanced inspections will significantly improve the probability of
crack detection while the parts are disassembled during maintenance.
All mandatory inspections must be conducted in accordance with detailed
inspection procedures prescribed in the manufacturer's Engine Manuals.
Additionally, this AD allows for air carriers operating under the
provisions of 14 CFR part 121 with an FAA-approved continuous
airworthiness maintenance program, and entities with whom those air
carriers make arrangements to perform this maintenance, to verify
performance of the enhanced inspections by retaining the maintenance
records that include the inspections resulting from this AD, provided
that the records include the date and signature of the person
performing the maintenance action. These records must be retained with
the maintenance records of the part, engine module, or engine until the
task is repeated. This will establish a method of record preservation
and retrieval typical to those in existing continuous airworthiness
maintenance programs. Instructions must be included in an air carrier's
maintenance manual providing procedures on how this record preservation
and retrieval system will be implemented and integrated into the air
carrier's record keeping system.
For engines or engine modules that are approved for return to
service by an authorized FAA-certificated entity and that are acquired
by an operator after the effective date of this AD, the mandatory
enhanced inspections need not be accomplished until the next piece-part
opportunity. For example, there is no need for an operator to
disassemble to piece-part level an engine or module returned to service
by an FAA-certificated facility simply because that engine or module
was previously operated by an entity not required to comply with this
AD. Furthermore, the FAA intends for operators to perform the enhanced
inspections of these parts at the next piece-part opportunity following
the initial acquisition, installation, and removal of the part
following the effective date of this AD. For piece parts that have not
been approved for return to service prior to the effective date of this
AD, the FAA does intend that the mandatory enhanced inspections
required by this AD be performed before such parts are approved for
return to service. Piece parts that have been approved for return to
service prior to the effective date of this AD may be installed;
however, enhanced inspection will be required at the next piece-part
opportunity.
This proposal would require, within the next 30 days after the
effective date of this AD, revisions to the Time Limits Section (TLS)
of the Engine Manuals, and, for air carriers, the approved continuous
airworthiness maintenance program. Pratt & Whitney, the manufacturer of
PW2000 series turbofan engines, used on 14 CFR part 25 airplanes has
provided the FAA with a detailed proposal that identifies and
prioritizes the critical life-limited rotating engine parts with the
highest potential to hazard the airplane in the event of failure, along
with instructions for enhanced, focused inspection methods. The
enhanced inspections resulting from this AD will be conducted at piece-
part opportunity, as defined below in the compliance section, rather
than specific time inspection intervals.
There are approximately 780 engines of the affected design in the
worldwide fleet. The FAA estimates that 650 engines installed on
airplanes of U.S. registry would be affected by this proposed AD, that
it would take approximately 8 work hours per engine to accomplish the
proposed actions, and that the average labor rate is $60 per work hour.
Based on these figures, and using recent shop visit rate data, the
total cost impact of the proposed AD on U.S. operators is estimated to
be approximately $145,000 per year.
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), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
Pratt & Whitney: Docket 98-ANE-61-AD.
Applicability: Pratt & Whitney PW2037, PW2040, PW2037M, PW2240,
PW2337, PW2043, PW2643, and PW2143, series turbofan engines,
installed on but not limited to Boeing 757 series and Ilyushin IL-
96T series airplanes.
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 critical life-limited rotating engine part failure,
which could result in an uncontained engine failure and damage to
the airplane, accomplish the following:
(a) Within the next 30 days after the effective date of this AD,
revise the manufacturer's Time Limits section of the manufacturer's
Engine Manual, Part Number 1A6231, as appropriate for the Pratt &
Whitney PW2037, PW2040, PW2037M, PW2240, PW2337, PW2043, PW2643, and
PW2143 series turbofan engines, and for air carriers revise the
approved continuous airworthiness maintenance program, by adding the
following:
``MANDATORY INSPECTIONS
(1) Perform inspections of the following parts at each piece-
part opportunity in
[[Page 46204]]
accordance with the instructions provided in the PW2000 series
Engine Manuals:
------------------------------------------------------------------------
Part number (P/N) Manual
Part nomenclature inspection section
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Hub, 1st Stg Comp................... 1A9001 (Assy P/N 72-31-04
1A9021).
Inspection -06.........
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(2) For the purposes of these mandatory inspections, piece-part
opportunity means:
(i) The part is considered completely disassembled when done in
accordance with the disassembly instructions in the manufacturers
engine manual; and
(ii) The part has accumulated more than 100 cycles in service
since the last piece-part opportunity inspection, provided that the
part was not damaged or related to the cause for its removal from
the engine.''
(b) Except as provided in paragraph (c) of this AD, and
notwithstanding contrary provisions in section 43.16 of the Federal
Aviation Regulations (14 CFR 43.16), these enhanced inspections
shall be performed only in accordance with the TLS of the
appropriate PW2000 series Engine Manuals.
(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 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
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 airplane to a location where
the requirements of this AD can be accomplished.
(e) The record of the mandatory inspections required as a result
of revising the Time Limits of the PW2000 series Engine Manuals as
provided by paragraph (a) of this AD shall be maintained by FAA-
certificated air carriers who have an approved continuous
airworthiness maintenance program in accordance with the record
keeping system currently specified in their manual required by
section 121.369 of the Federal Aviation Regulations (14 CFR
121.369); or, in lieu of the record showing the current status of
each mandatory inspection required by section 121.380(a)(2)(vi) of
the Federal Aviation Regulations (14 CFR 121.380(a)(2)(vi)),
certificated air carriers may establish an alternate system of
record retention that provides a method for preservation and
retrieval of the maintenance record that includes the inspections
resulting from this AD, and include the policy and procedures for
implementing this alternate method in the manual required by section
121.369(c) of the Federal Aviation Regulations (14 CFR 121.369(c))
provided the alternate system must require the maintenance record be
maintained either indefinitely or until the work is repeated.
Note 3: These record keeping requirements apply only to the
records used to document the mandatory enhanced inspections required
as a result of revising the Time Limits section of the PW2000 series
Engine Manuals as provided in paragraph (a) of this AD, and do not
alter or amend the record keeping requirements for any other AD or
regulatory requirement.
Issued in Burlington, Massachusetts, on August 25, 1998.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 98-23361 Filed 8-28-98; 8:45 am]
BILLING CODE 4910-13-U
