Document ID: FAA-2009-0811-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Rolls-Royce Corp. (RRC) AE 3007A Series Turbofan Engines
Posted Date: 2010-02-18T05:00Z

[Federal Register: February 18, 2010 (Volume 75, Number 32)]
[Proposed Rules]               
[Page 7209-7212]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18fe10-5]                         

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================

[[Page 7209]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0811; Directorate Identifier 2008-NE-41-AD]
RIN 2120-AA64

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

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

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for RRC AE 3007A series turbofan engines. This proposed AD would 
require removing or performing initial and repetitive eddy current 
inspections (ECIs) or surface wave ultrasonic testing (SWUT) 
inspections on high-pressure turbine (HPT) stage 2 wheels for cracks. 
This proposed AD also reduces the approved life limits of certain HPT 
stage 2 wheels. This proposed AD results from reports of cracked HPT 
stage 2 wheels. We are proposing this AD to prevent uncontained failure 
of the HPT stage 2 wheel and damage to the airplane.

DATES: We must receive any comments on this proposed AD by March 22, 
2010.

ADDRESSES: Use one of the following addresses to comment on this 
proposed 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: (202) 493-2251.
    You can get the service information identified in this proposed AD 
from Rolls-Royce Corporation, P.O. Box 420, Speed Code U15, 
Indianapolis, IN 46206-0420, e-mail: indy.pubs.services@rolls-
royce.com.

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: 
kyri.zaroyiannis@faa.gov; telephone (847) 294-7836; fax (847) 294-7834.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2009-0811; Directorate 
Identifier 2008-NE-41-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the proposed AD. We will consider 
all comments received by the closing date and may amend the proposed AD 
in light of those comments.
    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 proposed 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 proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    On September 8, 2008, we issued emergency AD 2008-19-51 that 
applied to RRC AE 3007A series turbofan engines. That AD required 
performing initial and repetitive eddy current inspections (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

    After we issued emergency AD 2008-19-51, we 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. The new risk assessment, in combination with a 
sufficient number of early inspections, showed that the risk profile 
was 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 2008-19-51. We 
changed the new compliance schedule to an interval of 150 cycles-in-
service (CIS) between wheel populations. The intervals for the wheel 
populations were based on CSN, and they varied because of the 
distribution of the affected wheels throughout the fleet at that time. 
A distribution based on CSN resulted in a compliance schedule that 
inspected the fleet from the highest time, highest risk

[[Page 7210]]

wheels to the lowest time, lowest risk wheels. It allowed us to control 
the overall risk consistent with the intent of AD 2008-19-51.
    We also 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 2008-19-51. Because of 
that determination, we no longer prohibit installing any engine that 
had 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 AD 
2008-26-06 or emergency AD 2008-19-51.
    Finally, we specified the part numbers (P/Ns) for the affected HPT 
stage 2 wheels to ensure proper identification.
    On December 12, 2008, we issued AD 2008-26-06 as an immediately 
adopted rule to mandate a short-term program (90 days) to ensure the 
continued airworthiness of the product. That AD published in the 
Federal Register on December 24, 2008 (73 FR 78927).

Actions Since AD 2008-26-06 Was Issued

    A few months after we issued AD 2008-26-06 we received reports of 
additional cracks in the HPT stage 2 wheels. A revised risk assessment 
that included these additional reports indicated that we needed to 
require a higher inspection rate. For this reason, we issued Emergency 
AD 2009-08-51 on April 10, 2009. That AD also provides instructions for 
an optional SWUT inspection. We then published a final rule; request 
for comments (74 FR 22091, May 12, 2009) to make the emergency actions 
applicable to all persons.
    We are now proceeding through the normal rule making process to 
ensure full public comment on our proposed actions. In this proposed 
AD, we are still requiring the same removal from service or ECI or SWUT 
inspections, but we are expanding the scope of the compliance schedule 
to more engines by including wheels with lower CSN. We are also 
including a requirement for repetitive inspections. In addition, we 
have identified by serial number a group of HPT stage 2 wheels that 
were repaired while in-service; because of this repair those wheels can 
only be inspected by the ECI method. We have also determined that the 
engine cycle life limit (ECLL) of the HPT stage 2 wheels, P/N 23075345 
and 23084520, covered by this proposed AD should be reduced to 23,000 
CSN and that the ECLL of all other part number HPT stage 2 wheels 
covered by this proposed AD should be reduced to 20,000 CSN on the 
effective date of this AD.
    The occurrence of cracked HPT stage 2 wheels has been shown by 
statistical analysis of field data to have a causal link to a 
manufacturing process that led to incomplete shot peening on the drive 
arm fillets (shaft inner diameter fillet) of the wheel. Improvements to 
the fixed manufacturing process have addressed this incomplete peening 
condition. Therefore, HPT stage 2 wheels that have been determined to 
have been fully shot peened in the drive arm fillet are excluded from 
the inspection requirements of this proposed AD.

Relevant Service Information

    We have reviewed and approved the technical contents of:
     RRC Alert Service Bulletin AE 3007A-A-72-367, Revision 2, 
dated June 22, 2009, that describes procedures for ECI of the HPT stage 
2 wheel on AE 3007A series engines.
     RRC Service Bulletin AE 3007A-72-368, Revision 2, dated 
April 28, 2009, that describes the procedures for SWUT inspection of 
the HPT stage 2 wheel on AE 3007A series turbofan engines.
     RRC Service Bulletin AE 3007A-72-369, Revision 2, dated 
November 5, 2009, that describes the procedures for SWUT inspection of 
the HPT stage 2 wheel on AE 3007A series turbofan engines.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would 
require:
     Removing from service any engine with certain P/N HPT 
stage 2 wheels that have a CSN specified in Table 1 of this AD by the 
compliance time specified in Table 1 of this AD; or
     Performing an ECI or SWUT inspection on certain P/N HPT 
stage 2 wheels that have a CSN specified in Table 1 of this AD by the 
compliance time specified in Table 1 of this AD; and
     Performing repetitive ECI or SWUT inspections of the HPT 
stage 2 wheels within 3,000 cycles-since-last inspection.
    You must use the service information described previously to 
perform the actions required by this AD.

Interim Action

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

Costs of Compliance

    We estimate that this proposed AD would affect 1402 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 2 work-hours per engine to perform both the proposed ECI and 
proposed SWUT. The average labor rate is $85 per work-hour. No parts 
are required for the inspection. We estimate the prorated life lost per 
stage 2 wheel is about $13,177. Based on these figures, we estimate the 
total cost of the proposed AD to U.S. operators to be $18,712,494. This 
estimate is exclusive of any warranty coverage.

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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 the proposed 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. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities

[[Page 7211]]

under the criteria of the Regulatory Flexibility Act.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. 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.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive:

Rolls-Royce Corporation (Formerly Allison Engine Company): Docket 
No. FAA-2009-0811; Directorate Identifier 2008-NE-41-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by March 22, 
2010.

Affected ADs

    (b) This AD supersedes AD 2009-08-51.

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) 23069438, 23069592, 23074462, 23074644, 
23075345, or 23084520 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 prevent 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.

HPT Stage 2 Wheels Exempted From the Inspection Requirements of This AD

    (f) The following engines are exempt from the inspection 
requirements of this AD:
    (1) All engines with an HPT stage 2 wheel, P/N 23084520.
    (2) All engines with an HPT stage 2 wheel, P/N 23075345, that 
has a serial number (S[sol]N) specified in Table 1 of this AD, and
    (3) All engines with an HPT stage 2 wheel, P/N 23074462, that 
has a S/N specified in Table 2 of this AD.

Table 1--HPT Stage 2 Wheel, P/N 23075345 by S/N Excluded From Inspection
                 Requirements (g) Through (i) of This AD
------------------------------------------------------------------------

------------------------------------------------------------------------
MM507646                 MM508211                 MM508319
MM508144                 MM508221                 MM508320
MM508153                 MM508241                 MM508322
MM508176                 MM508248                 MM508337
MM508186                 MM508251                 MM508338
MM508188                 MM508264                 MM508382
MM508205                 MM508305                 MM508387
MM508208                 MM508311
------------------------------------------------------------------------

Table 2--HPT Stage 2 Wheel, P/N 23074462 by S/N Excluded From Inspection
                 Requirements (g) Through (i) of This AD
------------------------------------------------------------------------

------------------------------------------------------------------------
MM504890                MM505025                MM505054
MM504963                MM505034                MM505055
MM504990                MM505041                MM505056
MM504995                MM505045                MM505061
MM505007                MM505046                All ``MM'' prefix S/Ns
                                                 higher than MM505061.
MM505017                MM505048                All S/Ns with ``MW''
                                                 prefix.
------------------------------------------------------------------------

Initial Eddy Current Inspection (ECI) or Surface Wave Ultrasonic 
Testing (SWUT) Inspection

    (g) For engines with an HPT stage 2 wheel, P/Ns 23069438, 
23069592, 23074462, 23074644, or 23075345, remove the engine from 
service or perform an initial inspection of the wheel by the cycle 
limit specified in Table 3 of this AD. Use one of the following 
methods for the inspection:
    (1) For HPT stage 2 wheels that have S/Ns listed in Table 4 of 
this AD, use paragraphs 2.A. through 2.C.(4) of RRC Alert Service 
Bulletin (ASB) AE 3007A-A-72-367, Revision 2 dated June 22, 2009, to 
inspect the wheel.
    (2) For HPT stage 2 wheels that have S/Ns not listed in Table 4 
of this AD, use paragraphs 2.A. through 2.C.(4) of RRC ASB AE 3007A-
A-72-367, Revision 2, dated June 22, 2009, or use paragraphs 2.A. 
through 2.N. of RRC Service Bulletin (SB) AE 3007A-72-368, Revision 
2, dated April 28, 2009; or use 2.A. through 2.V.(4) of RRC SB AE 
3007A-72-369, Revision 2, dated November 5, 2009, to perform the 
inspections.

 Table 3--Compliance Times for Engine Removal or ECI or SWUT Inspection
           of the HPT Stage 2 Wheels by Cycles-Since-New (CSN)
------------------------------------------------------------------------
                                          Remove engine from service or
    For HPT stage 2 wheels with the          inspect wheel within the
 following CSN on the effective date of    following cycles-in-service
                this AD:                  (CIS) after the effective date
                                                   of this AD:
------------------------------------------------------------------------
(3) 17,500 or more CSN.................  Remove engine from service or
                                          inspect before next flight.
(4) 10,000 to 17,499 CSN...............  15 CIS.
(5) 9,999 or fewer CSN.................  Before accumulating 10,015 CSN.
------------------------------------------------------------------------

 Table 4--S/Ns of HPT Stage 2 Wheels To Be Inspected by SB AE 3007A-72-
                          367 (ECI Method Only)
------------------------------------------------------------------------

------------------------------------------------------------------------
              HPT Stage 2 Wheels Requiring ECI Method Only
------------------------------------------------------------------------
MM119400                             MM183796
MM119480                             MM183808
MM119508                             MM183831
MM155847                             MM228730
MM155907                             MM228951
MM155908                             MM503748
MM183236                             MM504004
MM183362                             MM57188
MM183754                             MM57440
MM183762                             MM57480
------------------------------------------------------------------------

Installation Prohibition

    (h) 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 that has been removed as a result of the 
inspection requirements of this AD, unless the HPT stage 2 wheel was 
inspected as specified in RRC ASB AE 3007A-A-72-367, Revision 2, 
dated June 22, 2009; or RRC SB AE 3007A-72-368, Revision 2, dated 
April 28, 2009; or RRC SB AE 3007A-72-369, Revision 2, dated 
November 5, 2009.

Repetitive Inspection

    (i) Thereafter, within 3,000 cycles-since-last inspection, 
remove the engine from service until an ECI or SWUT inspection is 
performed on the HPT stage 2 wheel. Use paragraphs 2.A. through 
2.C.(4) of RRC ASB AE 3007A-A-72-367, Revision 2, dated June 22, 
2009, or use paragraphs 2.A. through 2.N. of RRC SB AE 3007A-72-368, 
Revision 2, dated April 28, 2009; or use 2.A. through 2.V.(4) of RRC 
SB AE 3007A-72-369, Revision 2, dated November 5, 2009, to inspect 
the wheel.

New, Reduced Engine Cycle Life Limit and Removal From Service

    (j) For HPT stage 2 wheels, P/N 23084520, do the following:
    (1) For wheels that have 22,985 CSN or more on the effective 
date of this AD, remove

[[Page 7212]]

the wheel from service within 15 CIS after the effective date of 
this AD.
    (2) Thereafter, remove HPT stage 2 wheels, P/N 23084520, before 
exceeding the new, reduced engine cycle life limit (ECLL) of 23,000 
CSN.
    (k) For HPT stage 2 wheels, P/N 23075345 and 23074644, do the 
following:
    (1) For wheels that have 19,985 CSN or more on the effective 
date of this AD, remove the wheel from service within 15 CIS after 
the effective date of this AD unless paragraph (k)(3) of this AD 
applies.
    (2) Thereafter, remove HPT stage 2 wheels, P/N 23075345 and 
23074644, before exceeding the new, reduced ECLL of 20,000 CSN.
    (3) For HPT stage 2 wheels, P/N 23075345, that have a S/N listed 
in Table 5 of this AD and that have 22,985 CSN or more on the 
effective date of this AD, remove the wheel from service within 15 
CIS after the effective date of this AD.
    (4) Thereafter, for HPT stage 2 wheels, P[sol]N 23075345, that 
have a S/N listed in Table 5 of this AD, remove the wheel from 
service before exceeding the new, reduced ECLL of 23,000 CSN.

 Table 5--S/Ns of HPT Stage 2 Wheel, P/N 23075345, Eligible To Remain in
                        Service Until 23,000 CSN
------------------------------------------------------------------------

------------------------------------------------------------------------
MM507646           MM508205           MM508251          MM508322
MM508144           MM508208           MM508264          MM508337
MM508153           MM508211           MM508305          MM508338
MM508176           MM508221           MM508311          MM508382
MM508186           MM508241           MM508319          MM508387
MM508188           MM508248           MM508320
------------------------------------------------------------------------

    (l) For wheels, P/N 23069438, in engines that have not complied 
with RRC SB AE 3007A-72-176, Revision 5, dated September 2, 2008, or 
SB AE 3007A-72-215, Revision 2, dated September 28, 2009, remove the 
wheel before exceeding the new, reduced ECLL of 10,000 CSN.
    (m) For wheels, P/N 23069438, in engines that have complied with 
RRC SB AE 3007A-72-176, Revision 5, dated September 2, 2008 or SB AE 
3007A-72-215, Revision 2, dated September 28, 2009, do the 
following:
    (1) For wheels that have 19,985 CSN or more on the effective 
date of this AD, remove the wheel from service within 15 CIS after 
the effective date of this AD.
    (2) Thereafter, remove the wheel from service before exceeding 
the new, reduced ECLL of 20,000 CSN.

Alternative Methods of Compliance

    (n) 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.

Special Flight Permits

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

Related Information

    (p) Contact Kyri Zaroyiannis, Aerospace Engineer, Chicago 
Aircraft Certification Office, Small Airplane Directorate, FAA, 2300 
E. Devon Ave., Des Plaines, IL 60018; e-mail: 
kyri.zaroyiannis@faa.gov; telephone (847) 294-7836; fax (847) 294-
7834, for more information about this AD.

    Issued in Burlington, Massachusetts, on February 11, 2010.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-3145 Filed 2-17-10; 8:45 am]
BILLING CODE 4910-13-P