

[Federal Register: October 11, 2007 (Volume 72, Number 196)]
[Rules and Regulations]               
[Page 57854-57857]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11oc07-6]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-23500; Directorate Identifier 2005-NE-46-AD; 
Amendment 39-15223; AD 2007-21-05]
RIN 2120-AA64

 
Airworthiness Directives; International Aero Engines (IAE) V2500 
Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
International Aero Engines (IAE) V2500 series turbofan engines. This AD 
requires repetitive monitoring of N2 vibration on all IAE V2500 series 
engines to identify engines that might have a cracked high pressure 
turbine (HPT) stage 2 air seal. This AD results from a report that HPT 
stage 2 air seals

[[Page 57855]]

have developed cracks. We are issuing this AD to prevent uncontained 
failure of the HPT stage 2 air seal.

DATES: This AD becomes effective November 15, 2007. The Director of the 
Federal Register approved the incorporation by reference of certain 
publications listed in the regulations as of November 15, 2007.

ADDRESSES: You can get the service information identified in this AD 
from International Aero Engines AG, 400 Main Street, East Hartford, CT 
06108; telephone: (860) 565-5515; fax: (860) 565-5510.
    The Docket Operations office is located at U.S. Department of 
Transportation, Docket Operations, West Building, Ground Floor, Room 
W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590-0001.

FOR FURTHER INFORMATION CONTACT: James Rosa, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; telephone (781) 238-7152; 
fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed AD. The proposed AD applies to IAE V2500 series 
turbofan engines. We published the proposed AD in the Federal Register 
on June 2, 2006 (71 FR 31978). That action proposed to require 
repetitive monitoring of N2 vibration on all IAE V2500 series engines 
to identify engines that might have a cracked HPT stage 2 air seal and 
to replace the seal as required.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov
; or in person at the Docket Operations office 

between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The street address for 
the Docket Operations office (telephone (800) 647-5527) is provided in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.
    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Comments

Parts To Be Monitored and Replaced

    The Modification and Replacement Parts Association states that the 
proposed AD does not list the part number(s) of seals requiring 
monitoring and replacement. We agree. To date, the following part 
numbers have failed: 2A3179, 2A3185, and 2A3425. However, all old 
design HPT stage 2 seals are subject to failure and should be vibration 
monitored and removed as required. We included a complete list of HPT 
stage 2 air seal part numbers in paragraph (c) of this AD.

Trend Slope

    The Air Transport Association and Delta Airlines state that we 
should better define the methodology for monitoring and determining 
trend slope. We disagree. Although these requirements are complex, they 
can be completed by trained personnel. We did not change the AD.

Tracking Compliance

    Delta Airlines states that we should provide guidance for tracking 
compliance with this AD, as current instructions are inadequate. We 
disagree. Operators should establish a system for showing compliance to 
this AD if they do not already have such a system. We did not change 
the AD.

Terminating Action

    Delta Airlines also states that we should include terminating 
action for the AD so they can estimate costs. We disagree. Terminating 
action is not currently available for the model V2500-A1 engine. 
Further, we discuss costs in the Costs of Compliance section of the AD. 
We did not change the AD.

Vibration Trend Monitoring

    Japan Airlines International states that vibration trend monitoring 
is not appropriate for an AD. The airline states that, because of the 
complex and subjective nature of vibration trend monitoring, accurate 
measurements are not possible. Therefore, trend monitoring is 
appropriate as a supplemental, nonmandatory activity only. We disagree. 
Vibration trend monitoring is successful in detecting cracked HPT 
seals. Although results are somewhat subjective, the system is the most 
practical way to prevent an unsafe condition due to cracked HPT seals. 
We did not change the AD.
    Japan Airlines International also states that industry needs a 
ground system to monitor vibration trends. We agree that a system to 
hold collected data and calculate trends as they occur is needed, 
however, defining requirements for that system is beyond the scope of 
this AD.
    United Airlines states that we should permit vibration data 
averaging and smoothing. They state that not allowing averaging will 
increase the chances of false alerts. We disagree. Experience indicates 
that averaging or smoothing might mask evidence of a badly cracked seal 
before a piece becomes liberated. We did not change the AD.

Clarify Service Bulletin Instructions

    Japan Airlines International states that we should clarify 
International Aero Engines service bulletin (SB) instructions regarding 
how gaps allowed by the Mandatory Minimum Equipment List (MMEL) effect 
data. MMEL allows a 10-day down time for the vibration trend monitoring 
system. We disagree. IAE service instructions allow a down time of 50 
cycles, approximately 10 days for most operators. If operators require 
more time, they may request an AMOC. We did not change the AD.

Manufacturer's Suggestions

    IAE suggests the following:
     Include the latest SB revisions in the final rule. We 
agree and incorporated by reference the accomplishment instructions of 
the latest IAE SB revisions in the final rule. Operators who have 
followed earlier SBs will receive credit for doing so.
     Correct the Discussion section regarding an incorrectly 
identified model from V2528-D to V2528-D5. We agree that the Discussion 
section should have specified the correct models, however, that 
discussion remained accurate for the engines subject to the AD. We did 
not change the AD because the Preamble of the NPRM is not included in 
the final rule.
     Include the Airbus A321 in the Applicability section. We 
agree. We have added the airplane model to the Applicability section.
     Reword the Compliance section to maintain consistent 
safety requirements. We agree, and included paragraphs (h)(4) and 
(j)(4) in the AD. These paragraphs now indicate that if a through crack 
is found in the front fillet radius of the HPT stage 2 air seal, the 
following must also be removed: For model V2500-A1/A5/D5 engines, 
remove the HPT stage 1 disk and HPT rear air seals; and for model 
V2500-A1 engines, also remove the HPT stage 2 disk.
     List only SB V2500-ENG-72-502, Revision 1, dated March 15, 
2006, under Removal of HPT Stage 2 Air Seals at Opportunity. We agree, 
and removed IAE SB V2500-ENG-72-0500 and IAE SB V2500-ENG-72-0501, 
which refer to vibration monitoring, from this section.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting

[[Page 57856]]

the AD with the changes described previously. We have determined that 
these changes will neither increase the economic burden on any operator 
nor increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 1,022 engines installed on 
airplanes of U.S. registry. We also estimate that it would take about 2 
work-hours per engine to perform the actions, and that the average 
labor rate is $80 per work-hour. Required parts would cost about 
$97,040 per engine. Based on these figures, we estimate the total cost 
of the AD to U.S. operators to be $99,338,400.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866;
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and
    (3) 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.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2007-21-05 International Aero Engines: Amendment 39-15223. Docket 
No. FAA-2005-23500; Directorate Identifier 2005-NE-46-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective November 
15, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to International Aero Engines (IAE) model 
V2500-A1, V2522-A5, V2524-A5, V2527-A5, V2527E-A5, V2527M-A5, V2530-
A5, V2533-A5, V2525-D5, and V2528-D5 turbofan engines with high 
pressure turbine (HPT) stage 2 air seals, part numbers (P/Ns) 
2A0487, 2A1159, 2A1160, 2A3108, 2A3179, 2A3185, 2A3425, and 2A3596, 
installed. These engines are installed on, but not limited to, 
Airbus A319, A320, A321, and Boeing MD-90 airplanes.

Unsafe Condition

    (d) This AD results from a report that HPT stage 2 air seals 
have developed cracks. We are issuing this AD to prevent uncontained 
failure of the HPT stage 2 air seal.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.

Monitoring N2 Vibration on All IAE Model V2500-A1 and V2522-A5, V2524-
A5, V2527-A5, V2527E-A5, V2527M-A5, V2530-A5, and V2533-A5 Engines

    (f) For IAE model V2530-A5 and V2533-A5 engines operated at 
30,000 or 33,000 pounds of thrust, or for model V2522-A5, V2524-A5, 
V2527-A5, V2527E-A5, and V2527M-A5 engines that have ever operated 
in the 30,000 or 33,000 pound thrust range, begin monitoring for N2 
vibration trend if the HPT stage 2 air seal reaches 4,000 cycles-
since-new (CSN) or more.
    (g) For IAE model V2500-A1 and V2522-A5, V2524-A5, V2527-A5, 
V2527E-A5, and V2527M-A5 engines operated below 30,000 pounds of 
thrust, begin monitoring for N2 vibration trend if the HPT stage 2 
air seal reaches 6,000 CSN.
    (h) Monitor N2 vibration trend of each engine for every 100 to 
150 cycles of engine operation as follows:
    (1) Use the Accomplishment Instructions of IAE Service Bulletin 
(SB) V2500-ENG-72-0500, Revision 1, dated July 14, 2006, to gather 
and monitor steady-state cruise N2 vibration data.
    (2) For a trend that has a slope of 0.001 units per cycle or 
greater and less than 0.003 units per cycle, remove the seal 250 
cycles from the point at which the slope begins to increase and do 
not reinstall it in any V2500 engine.
    (3) For a trend that has a slope of 0.003 units per cycle or 
greater, remove the seal in 10 cycles and do not reinstall it in any 
V2500 engine.
    (4) If a through crack is found in the front fillet radius of 
the HPT stage 2 air seal, remove the following:
    (i) For the A1 model engine, remove the HPT stage 1 and 2 disks 
and HPT stage 1 rear air seals (64 per engine) and do not reinstall 
them in any V2500 engine.
    (ii) For all A5 engine models, remove the HPT stage 1 disk and 
the HPT stage 1 rear air seals (64 per engine) and do not reinstall 
them in any V2500 engine.
    (5) Use Section 3, Accomplishment Instructions, of IAE SB V2500-
ENG-72-0502, Revision 1, dated March 15, 2006, for removal 
procedures.

Monitoring N2 Vibration on All IAE Model V2525-D5 and V2528-D5 Engines

    (i) For all IAE model V2500-D5 series engines, begin monitoring 
for N2 vibration trend if the HPT stage 2 air seal reaches 6,000 CSN 
or more.
    (j) Monitor N2 vibration trend of each engine for every 100 to 
150 cycles of engine operation as follows:
    (1) Use Section 3, Accomplishment Instructions, of IAE SB V2500-
ENG-72-0501, Revision 1, dated July 14, 2006, to gather and monitor 
the steady-state cruise N2 vibration data.
    (2) If an increasing trend that has a slope of 0.0007 units per 
cycle or greater, and less than 0.002 units per cycle is observed, 
remove the HPT stage 2 air seal within 250 cycles from the point at 
which the slope begins to increase and do not reinstall it in any 
V2500 engine.
    (3) If an increasing trend that has a slope of 0.002 units per 
cycle or greater is observed, remove the HPT stage 2 air seal within 
10 cycles and do not reinstall it in any V2500 engine.
    (4) If a through crack is found in the front fillet radius of 
the HPT stage 2 air seal of D5 model engines, remove the HPT stage 1 
disk and HPT rear air seals (64 per engine) and do not reinstall 
them in any V2500 engine.
    (5) Use Section 3, Accomplishment Instructions, of IAE SB V2500-
ENG-72-0502, dated March 15, 2006, for removal procedures.

[[Page 57857]]

Removal of HPT Stage 2 Air Seals at Opportunity

    (k) For all engines, when the HPT stage 2 air seal reaches 2,000 
CSN, remove the HPT stage 2 air seal at the next separation of the 
HPT stage 1 and 2 rotors and do not reinstall it in any V2500 
engine.

Definition

    (l) For the purposes of this AD, ``At Opportunity'' is defined 
as when the engine is disassembled, the HPT stage 2 seal is exposed, 
and the HPT stage 1 and 2 rotors are separated after 2,000 CSN.
    (m) The Accomplishment Instructions of IAE SB V2500-ENG-72-0502, 
Revision 1, dated March 15, 2006, provide information on removing 
the HPT stage 2 air seal.

Alternative Methods of Compliance

    (n) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (o) Contact James Rosa, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: james.rosa@faa.gov, 
telephone (781) 238-7152; fax (781) 238-7199, for more information 
about this AD.

Material Incorporated by Reference

    (p) You must use the Accomplishment Instructions (Section 3.) of 
International Aero Engines (IAE) Service Bulletin (SB) V2500-ENG-72-
0500, Revision 1, dated July 14, 2006; IAE SB V2500-ENG-72-0501, 
Revision 1, dated July 14, 2006; or IAE SB V2500-ENG-72-0502, 
Revision 1, dated March 15, 2006, to perform the actions required by 
this AD. The Director of the Federal Register approved the 
incorporation by reference of these service bulletins in accordance 
with 5 U.S.C. 552(a) and 1 CFR part 51. Contact International Aero 
Engines AG, 400 Main Street, East Hartford, CT 06108; telephone: 
(860) 565-5515; fax: (860) 565-5510 for a copy of this service 
information. You may review copies at the FAA, New England Region, 
12 New England Executive Park, Burlington, MA; or at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call 202-741-6030, or go to: 
http://www.archives.gov/federal-register/cfr/ibr-locations.html.


    Issued in Burlington, Massachusetts, on October 2, 2007.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E7-19924 Filed 10-10-07; 8:45 am]

BILLING CODE 4910-13-P
