[Federal Register Volume 64, Number 3 (Wednesday, January 6, 1999)]
[Proposed Rules]
[Pages 787-789]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-254]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-76-AD]
RIN 2120-AA64
Airworthiness Directives; International Aero Engines AG (IAE)
V2500-A1 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 International Aero Engines (IAE)
V2500-A1 series turbofan engines. This proposal would require initial
and repetitive inspections of certain High Pressure Turbine (HPT) stage
1 and stage 2 disks utilizing an improved ultrasonic method when the
disks are exposed during a normal shop visit, and if a subsurface
anomaly is found, removal from service and replacement with a
serviceable part. This proposal is prompted by the results of a stage 1
HPT disk fracture investigation which has identified a population of
HPT stage 1 and 2 disks that may have subsurface anomalies formed
during a forging process. The actions specified by the proposed AD are
intended to prevent
[[Page 788]]
HPT disk fracture, which could result in an uncontained engine failure,
and damage to the aircraft.
DATES: Comments must be received by February 5, 1999.
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-76-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be sent
via the Internet using the following address: ``engineprop@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.
The service information referenced in the proposed rule may be
obtained from Rolls-Royce Commercial Aero Engine Limited, P. O. Box 31,
Derby, England, DE2488J, Attention: Publication Services ICL-TP;
telephone number 011-44-1-33-22-46553; fax number 011-44-1-33-22-46302.
This information may be examined at the FAA, New England Region, Office
of the Regional Counsel, 12 New England Executive Park, Burlington, MA.
FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine
Certification Office, FAA, Engine and Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-
7133, 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-76-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-76-AD, 12 New England Executive
Park, Burlington, MA 01803-5299.
Discussion
The Federal Aviation Administration (FAA) received a report of an
uncontained high pressure turbine (HPT) disk failure on an
International Aero Engines (IAE) V2500-A1 series turbofan engine
installed on an Airbus A320 series aircraft. Based on the results of
the preliminary investigation, which indicated that the fracture
initiated from material contamination, the FAA issued airworthiness
directive (AD) 98-20-18, which immediately removed from service 6 HPT
disks made from the same batch of material as the fractured disk.
Further investigation revealed that no material contamination was
present in the fracture initiation area of the failed disk. The
subsurface defect was a ``clean linear'' anomaly within the parent
material formed during a specific forging process. The current
ultrasonic inspection methods utilized during the disk manufacturing of
the failed disk may not have been capable of detecting this defect due
to its orientation and shape. Therefore, the suspect population has
been expanded to include all HPT stage 1 and stage 2 disks manufactured
between 1983 and early 1992, using the same specific forging process.
HPT disks manufactured after early 1992 are not suspect because a
different forging process was utilized. There is a total of 302 disks
in this suspect population. This condition, if not corrected, could
result in an HPT disk fracture, which could result in a uncontained
engine failure, and an inflight engine shutdown.
The FAA has reviewed and approved the technical contents of IAE
Service Bulletin (SB) No. V2500-ENG-72-0344, dated December 18, 1998,
that describes inspection procedures and criteria for certain stage 1
and 2 HPT 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 initial and repetitive inspections of certain
stage 1 and stage 2 HPT disks using an improved ultrasonic method
whenever the disk is accessible during a shop visit. At this time, only
one source is capable of performing the necessary inspection procedure.
Therefore, the disks will be sent to this source, as specified in the
Service Bulletin, to accomplish the inspections. Those HPT disks
rejected at inspection may not be reinstalled and must be replaced with
a serviceable part. The actions would be required to be accomplished in
accordance with the SB described previously.
There are approximately 302 affected disks installed in engines in
the worldwide fleet. The FAA estimates that 38 stage 1 HPT disks and 30
stage 2 HPT disks are installed in 38 engines on aircraft of U.S.
registry that would be affected by this proposed AD. The FAA estimates
that the shipping cost per disk to the facility which will inspect the
disk and its return will be approximately $140, that the inspection
would take approximately 8 work hours per disk to accomplish the
proposed actions, and that the average labor rate is $60 per work hour.
On average the disk will be exposed and inspected three times in its
service life. Based on these figures, the total cost impact of the
proposed AD on U.S. operators is estimated to be $113,480. The
manufacturer has advised the FAA that all costs associated with
performing these inspections may be reimbursed to the operator.
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
[[Page 789]]
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:
International Aero Engines AG: Docket No. 98-ANE-76-AD.
Applicability: International Aero Engines AG (IAE) Models V2500-
A1 series turbofan engines, installed on Airbus A320 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 (d) 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 high pressure turbine (HPT) disk fracture, which
could result in an uncontained engine failure and damage to the
aircraft, accomplish the following:
(a) Ultrasonic inspect for subsurface anomalies those HPT stage
1 and stage 2 disks, with serial numbers listed in Tables 1, 2, 3,
and 4 of IAE Service Bulletin (SB) V2500-ENG-72-0344, dated December
18, 1998, at the first opportunity when the engine is disassembled
sufficiently to afford access to the High Pressure Turbine (HPT)
subassembly, or no later than 10,000 cycles in service (CIS) from
the effective date of this AD, whichever occurs first, in accordance
with Paragraphs F (1) and (2) of IAE SB V2500-ENG-72-0344, dated
December 18, 1998.
(b) Thereafter, repetitively ultrasonic inspect for subsurface
anomalies those HPT disks identified in paragraph (a) whenever the
engine is disassembled sufficiently to afford access to the HPT
subassembly, or no later than 12,000 CIS since last ultrasonic
inspection, whichever occurs first, in accordance with Paragraph F
(1) and (2) of IAE SB V2500-ENG-72-0344, dated December 18, 1998.
(c) Those HPT disks rejected at inspection may not be
reinstalled and must be replaced with a serviceable part.
(d) 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.
(e) 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.
Issued in Burlington, Massachusetts, on December 30, 1998.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 99-254 Filed 1-5-99; 8:45 am]
BILLING CODE 4910-13-U
