[Federal Register: December 24, 2008 (Volume 73, Number 248)]
[Rules and Regulations]
[Page 78927-78929]
[DOCID:fr24de08-3]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0975; Directorate Identifier 2008-NE-29-AD;
Amendment 39-15772; AD 2008-26-06]
RIN 2120-AA64

Airworthiness Directives; Rolls-Royce Corporation (RRC) AE 3007A
Series Turbofan Engines

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

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is superseding emergency airworthiness directive (AD)
2008-19-51 that we sent previously to all known U.S. owners and
operators of RRC AE 3007A series turbofan engines. That AD requires
performing initial and repetitive eddy current inspections (ECIs) on
the high-pressure turbine (HPT) stage 2 wheel for cracks. This AD
continues to require those same inspections, but revises the compliance
schedule for the initial inspection and specifies the affected HPT
stage 2 wheels by part number (P/N). This AD results from reports of
cracked HPT stage 2 wheels. We are issuing this AD to detect cracks in
the HPT stage 2 wheel, which could result in a possible uncontained
failure of the HPT stage 2 wheel and damage to the airplane.

DATES: Effective January 8, 2009.
    We must receive any comments on this AD by February 23, 2009.

ADDRESSES: Use one of the following addresses to comment on this AD.
     Federal eRulemaking Portal: Go to http://
www.regulations.gov and follow the instructions for sending your
comments electronically.
     Mail: Docket Management Facility, U.S. Department of
Transportation, 1200 New Jersey Avenue, SE., West Building Ground
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax:<PHONE_NUMBER>.
    Contact Rolls-Royce Corporation, P.O. Box 420, Speed Code U15,
Indianapolis, IN 46206-0420, e-mail: indy.pubs.services@rolls-
royce.com, for the service information identified in this AD.

FOR FURTHER INFORMATION CONTACT: Kyri Zaroyiannis, Aerospace Engineer,
Chicago Aircraft Certification Office, Small Airplane Directorate, FAA,
2300 E. Devon Ave., Des Plaines, IL 60018; e-mail:
<EMAIL_ADDRESS>telephone<PHONE_NUMBER>; fax<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION: On September 8, 2008, we issued emergency AD
2008-19-51, that applies to RRC AE 3007A series turbofan engines. That
AD requires performing initial and repetitive ECIs on HPT stage 2
wheels that have accumulated 6,500 or more cycles-since-new (CSN). That
AD resulted from reports of HPT stage 2 wheels that had cracks in the
bores of the wheels. This condition, if not corrected, could result in
a possible uncontained failure of the HPT stage 2 wheel, which could
cause damage to the airplane.

Actions Since AD 2008-19-51 Was Issued

    Since we issued that AD, we have determined that the cracks in the
HPT stage 2 wheel bores are caused by a thermally-induced high stress
in the disk bore which was not identified at the time of the original
certification. We performed a new risk assessment for cracking in the
bore of the HPT stage 2 wheel using the FAA methodology guidelines in
FAA Advisory Circular 39.8 and the results of the inspections from AD
2008-19-51. The risk

assessment takes into account physical characteristics about the cracks
that were not available when we issued AD 2008-19-51. This risk
assessment, in combination with a sufficient number of early
inspections relative to the existing AD, shows that the risk profile is
not rapidly increasing, which was a concern when we issued AD 2008-19-
51. Using this new information, we determined we could change the
compliance requirements for the ECI while still maintaining a level of
safety consistent with the intent of the original AD. We changed the
new compliance schedule to an interval of 150 cycles-in-service (CIS)
between wheel populations. The intervals for the wheel populations are
based on CSN and they vary because of the current distribution of the
affected wheels throughout the fleet. This distribution results in a
compliance schedule that inspects the fleet from the highest time,
highest risk wheels to the lowest time, lowest risk wheels, and allows
us to control the overall risk consistent with the intent of the
original AD.
    We determined that a requirement to perform the ECI by a certain
CIS is by itself sufficient to maintain the level of safety consistent
with the intent of the original AD. Because of that determination, we
no longer prohibit installing any engine that has an HPT stage 2 wheel
with more than 6,500 CSN unless the wheel was inspected. Instead, we
modified that requirement to apply only to HPT stage 2 wheels removed
from service as a result of complying with this AD.
    Finally, we specify the P/Ns for the affected HPT stage 2 wheels to
ensure proper identification.

Relevant Service Information

    We have reviewed and approved the technical contents of RRC Alert
Service Bulletin (ASB) AE 3007A-A-72-367, dated September 5, 2008. That
ASB describes procedures for ECI of the HPT stage 2 wheel on AE 3007A
series engines.

FAA's Determination and Requirements of This AD

    The unsafe condition described previously is likely to exist or
develop on other RRC AE 3007A series turbofan engines of the same type
design. We are issuing this AD to detect cracks in the HPT stage 2
wheel, which could result in a possible uncontained failure of the HPT
stage 2 wheel and damage to the airplane. This AD requires:
     Removing from service any engine with certain P/N HPT
stage 2 wheels by the compliance time specified in Table 1 of this AD;
and
     Performing an ECI on any HPT stage 2 wheel in any engine
that was removed from service as a requirement of this AD before
returning that HPT stage 2 wheel to service.

FAA's Determination of the Effective Date

    Since an unsafe condition exists that requires the immediate
adoption of this AD, we have found that notice and opportunity for
public comment before issuing this AD are impracticable, and that good
cause exists for making this amendment effective in less than 30 days.

Interim Action

    These actions are interim actions and we may take further
rulemaking actions in the future.

Comments Invited

    This AD is a final rule that involves requirements affecting flight
safety and was not preceded by notice and an opportunity for public
comment; however, we invite you to send us any written relevant data,
views, or arguments regarding this AD. Send your comments to an address
listed under ADDRESSES. Include ``AD Docket No. FAA-2008-0975;
Directorate Identifier 2008-NE-29-AD'' in the subject line of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify it.
    We will post all comments we receive, without change, to http://
www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact
with FAA personnel concerning this AD. Using the search function of the
Web site, anyone can find and read the comments in any of our dockets,
including, if provided, the name of the individual who sent the comment
(or signed the comment on behalf of an association, business, labor
union, etc.). You may review the DOT's complete Privacy Act Statement
in the Federal Register published on April 11, 2000 (65 FR 19477-78).

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<PHONE_NUMBER>) is the same as
the mail address provided in the ADDRESSES section. Comments will be
available in the AD docket shortly after receipt.

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 the 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, Safety.

Adoption of the Amendment

    Under the authority delegated to me by the Administrator, the
Federal Aviation Administration amends part 39 of the Federal Aviation
Regulations (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 a new airworthiness directive,
Amendment 39-15772, to read as follows:

2008-26-06 Rolls-Royce Corporation (Formerly Allison Engine
Company): Amendment 39-15772. Docket No. FAA-2008-0975; Directorate
Identifier 2008-NE-29-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective January
8, 2009.

Affected ADs

    (b) This AD supersedes emergency AD 2008-19-51.

Applicability

    (c) This AD applies to Rolls-Royce Corporation (RRC) AE 3007A
series turbofan engines with high-pressure turbine (HPT) stage 2
wheels, part numbers (P/Ns) 23065892, 23069116, 23069438, 23069592,
23074462, 23074644, 23075345, 23084520, or 23084781, installed.
These engines are installed on, but not limited to, Empresa
Brasileira de Aeronautica S. A. (EMBRAER) EMB-135 and EMB-145
airplanes.

Unsafe Condition

    (d) This AD results from reports of cracked HPT stage 2 wheels.
We are issuing this AD to detect cracks in the HPT stage 2 wheel,
which could result in a possible uncontained failure of the HPT
stage 2 wheel and damage to the airplane.

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.

Removing Engines From Service

    (f) For engines with an HPT stage 2 wheel, P/Ns 23065892,
23069116, 23069438, 23069592, 23074462, 23074644, 23075345,
23084520, or 23084781, remove the engine from service by the cycles-
in-service (CIS) specified in Table 1 of this AD.

 Table 1--Compliance Times for Engine Removal for ECI of the HPT Stage 2
                                 Wheels
------------------------------------------------------------------------
 If the HPT stage 2 wheel has accumulated    Then remove the engine from
     on the effective date of this AD:                service:
------------------------------------------------------------------------
16,200 cycles-since-new (CSN) or more.....  Within 150 CIS.
15,800 to 16,199 CSN......................  Within 300 CIS.
15,500 to 15,799 CSN......................  Within 450 CIS.
------------------------------------------------------------------------

Installation Prohibition

    (g) After the effective date of this AD, don't return to
service, any HPT stage 2 wheel that was installed in any RRC AE
3007A series engine removed as a result of paragraph (f) of this AD,
unless the HPT stage 2 wheel was inspected as specified in RRC Alert
Service Bulletin (ASB) AE 3007A-A-72-367, dated September 5, 2008.

Alternative Methods of Compliance

    (h) The Manager, Chicago Aircraft 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.
    (i) Alternative Methods of Compliance (AMOCs) currently approved
for AD 2008-19-51 will remain in effect until the effective date for
this AD. After that date the AMOCs will expire.

Special Flight Permits

    (j) Under 14 CFR part 39.23, we are limiting the special flight
permits for this AD by restricting the flight to essential flight
crew only.

Related Information

    (k) Contact Kyri Zaroyiannis, Aerospace Engineer, Chicago
Aircraft Certification Office, Small Airplane Directorate, FAA, 2300
E. Devon Ave., Des Plaines, IL 60018; e-mail:
<EMAIL_ADDRESS>telephone<PHONE_NUMBER>; fax (847) 294-
7834, for more information about this AD.
    (l) Rolls-Royce Corporation ASB AE 3007A-A-72-367, dated
September 5, 2008, contains information on performing ECIs on HPT
stage 2 wheels. Contact Rolls-Royce Corporation, P.O. Box 420, Speed
Code U15, Indianapolis, IN 46206-0420; e-mail:
<EMAIL_ADDRESS>for a copy of this service
information.

Material Incorporated by Reference

    (m) None.

    Issued in Burlington, Massachusetts, on December 12, 2008.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
 [FR Doc. E8-30051 Filed 12-23-08; 8:45 am]

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