[Federal Register Volume 64, Number 150 (Thursday, August 5, 1999)]
[Proposed Rules]
[Pages 42619-42622]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-20184]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NE-36-AD]
RIN 2120-AA64
Airworthiness Directives; AlliedSignal Inc. ALF502R and LF507
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 Chapter 5,
Airworthiness Limitations section, of the AlliedSignal Inc. ALF502R and
LF507 series Engine Manuals 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 a Federal Aviation Administration (FAA) study of in-service
events involving uncontained failures of critical rotating engine parts
that indicated the need for improved inspections. The improved
inspections are needed to identify those critical rotating parts with
conditions, which 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.
[[Page 42620]]
DATES: Comments must be received by November 3, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Regional
Counsel, Attention: Rules Docket No. 99-NE-36-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be sent
via the Internet using the following address: ``adcomment@faa.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: Raymond Vakili, Aerospace Engineer Los
Angeles Aircraft Certification Office, FAA, Transport Airplane
Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone
(562) 627-5262, fax (562) 627-5210.
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 99-NE-36-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. 99-NE-36-AD, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
A recent Federal Aviation Administration (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 disks which
could most likely result in a safety hazard to the airplane in the
event of a disk fracture. The FAA is also considering the need for
additional rule making. 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 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.
This proposal would require, within the next 30 days after the
effective date of this AD, revisions to Chapter 5, Airworthiness
Limitations section, of the AlliedSignal Inc. ALF502R and LF507 series
Engine Manuals and, for air carriers, the approved continuous
airworthiness maintenance program. AlliedSignal Inc., the manufacturer
of ALF502R and LF507 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.
[[Page 42621]]
The FAA estimates that 200 engines installed on airplanes of US
registry would be affected by this proposed AD, that it would take
approximately 56 work hours per engine to accomplish the proposed
actions. The average labor rate is $60 per work hour. Based on these
figures, the total cost impact of the proposed AD on US operators is
estimated to be $672,000.
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:
AlliedSignal Inc.: Docket 99-NE-36-AD.
Applicability: AlliedSignal Inc. (formerly Textron Lycoming and
Avco Lycoming) ALF502R and LF507 series turbofan engines, installed
on but not limited to British Aerospace BAe 146-100A, BAe 146-200A,
BAe 146-300A, AVRO 146-RJ70A, AVRO 146-RJ85A, and AVRO 146-100A
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 Chapter 5, e Airworthiness Limitations section, of the
AlliedSignal Inc. ALF502R and LF507 Engine Manuals, and for air
carrier operations revise the approved continuous airworthiness
maintenance program, by adding the following:
``Chapter 5, Airworthiness Limitations Section, Mandatory
Inspections:
(1) Perform inspections of the following parts at each piece-
part opportunity in accordance with the instructions provided in the
applicable manual provisions:
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Part nomenclature Part number (P/N) Inspect per engine manual chapter
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For ALF502R series turbofan engines:
Fan Disc.......................... All...................... 72-31-07 Inspection/Check.
First Turbine Disc................ All...................... 72-51-12 Inspection/Check.
Second Turbine Disc............... All...................... 72-51-21 Inspection/Check.
Impeller.......................... All...................... 72-34-38 Inspection/Check.
Low Pressure Turbine Shaft:
(Third Turbine)................... All...................... 72-52-03 Inspection/Check.
Fourth Turbine Disc............... All...................... 72-52-06 Inspection/Check.
For LF507 series turbofan engines:
Fan Disc.......................... All...................... 72-31-08 Inspection/Check.
First Turbine Disc................ All...................... 72-51-11 Inspection/Check.
Second Turbine Disc............... All...................... 72-51-20 Inspection/Check.
Impeller.......................... All...................... 72-34-20 Inspection/Check.
Low Pressure Turbine Shaft:
(Third Turbine)................... All...................... 72-52-24 Inspection/Check.
Fourth Turbine Disc............... All...................... 72-52-03 Inspection/Check.
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(2) For the purposes of these mandatory inspections, piece-part
opportunity means:
(i) The part is completely disassembled when done in accordance
with the disassembly instructions in the engine manufacturer's
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 mandatory inspections
shall be performed only in accordance with Chapter 5, Airworthiness
Limitations section, of the AlliedSignal Inc. ALF502R and LF507
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 Manager, Los Angeles Aircraft Certification
Office. Operators shall submit their requests through an appropriate
FAA Principal Maintenance Inspector (PMI), who may add comments and
then send it to the Manager, Los Angeles Aircraft 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 Los Angeles Aircraft 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.
[[Page 42622]]
(e) FAA-certificated air carriers that have an approved
continuous airworthiness maintenance program in accordance with the
record keeping requirement of Sec. 121.369 (c) of the Federal
Aviation Regulations [14 CFR 121.369 (c)] of this chapter must
maintain records of the mandatory inspections that result from
revising the Engine Manual's Chapter 5, Airworthiness Limitations
section, and the air carrier's continuous airworthiness program.
Alternately, certificated air carriers may establish an approved
system of record retention that provides a method for preservation
and retrieval of the maintenance records that include the
inspections resulting from this AD, and include the policy and
procedures for implementing this alternate method in the air
carrier's maintenance manual required by Sec. 121.369 (c) of the
Federal Aviation Regulations [14 CFR 121.369 (c)]; however, the
alternate system must be accepted by the appropriate PMI and require
the maintenance records be maintained either indefinitely or until
the work is repeated. Records of the piece-part inspections are not
required under Sec. 121.380 (a) (2) (vi) of the Federal Aviation
Regulations [14 CFR 121.380 (a) (2) (vi)]. All other operators must
maintain the records of mandatory inspections required by the
applicable regulations governing their operations.
Note 3: The requirements of this AD have been met when the
engine manual changes are made and air carriers have modified their
continuous airworthiness maintenance plans to reflect the
requirements in the Engine Manuals.
Issued in Burlington, Massachusetts, on July 30, 1999.
Jorge A. Fernandez,
Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 99-20184 Filed 8-4-99; 8:45 am]
BILLING CODE 4910-13-P
