[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: ``9-ad-
[email protected]''. 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