AD 2012-10-12

final rule

Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

AD Number
2012-10-12
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Docket No. FAA-2007-28059
FR Citation
77 FR 31176
Technical illustration of an aircraft turbine engine assembly
Problem area Engine

Applicability

TypeManufacturerModelDetails
aircraft Rolls-Royce Various Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

Unsafe Condition

Cracking on the intermediate-pressure (IP) compressor rotor rear balance land, which can lead to uncontained failure of the rotor and damage to the airplane.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Inspect the IP compressor rotor shaft rear balance land for cracks. Perform initial inspections, additional inspections, and a mandatory terminating action as specified in the AD.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within the compliance times specified in the AD, which vary based on the inspection type and engine model.

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Rolls-Royce RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

We are superseding an existing airworthiness directive (AD) for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That AD currently requires inspecting the intermediate-pressure (IP) compressor rotor shaft rear balance land for cracks. This new AD continues to require initial inspections, adds additional inspections, and a mandatory terminating action. This AD was prompted by additional cracking on RB211-Trent 700 and RB211-Trent 800 IP compressor rotor shafts found since the existing AD was issued. We are issuing this AD to detect cracking on the IP compressor rotor rear balance land. IP compressor rotor rear balance land cracking can lead to uncontained failure of the rotor and damage to the airplane.

Applicability Source Text

Show captured applicability text from the source AD
(c) Applicability

    This AD applies to Rolls-Royce plc (RR) RB211-Trent 553-61, 
553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 
768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 
892B-17, and 895-17 turbofan engines.

Document Text

Show stored source text (verify against official source)
[Federal Register Volume 77, Number 102 (Friday, May 25, 2012)]
[Rules and Regulations]
[Pages 31176-31178]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2012-12726]



[[Page 31176]]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28059; Directorate Identifier 2007-NE-13-AD; 
Amendment 39-17061; AD 2012-10-12]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce plc (RR) Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: We are superseding an existing airworthiness directive (AD) 
for all RR RB211-Trent 553-61, 553A2-61, 556-61, 556A2-61, 556B-61, 
556B2-61, 560-61, 560A2-61, 768-60, 772-60, 772B-60, 875-17, 877-17, 
884-17, 884B-17, 892-17, 892B-17, and 895-17 turbofan engines. That AD 
currently requires inspecting the intermediate-pressure (IP) compressor 
rotor shaft rear balance land for cracks. This new AD continues to 
require initial inspections, adds additional inspections, and a 
mandatory terminating action. This AD was prompted by additional 
cracking on RB211-Trent 700 and RB211-Trent 800 IP compressor rotor 
shafts found since the existing AD was issued. We are issuing this AD 
to detect cracking on the IP compressor rotor rear balance land. IP 
compressor rotor rear balance land cracking can lead to uncontained 
failure of the rotor and damage to the airplane.

DATES: This AD is effective June 29, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of June 29, 2012.

ADDRESSES: For service information identified in this AD, contact 
Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, England, 
DE248BJ; phone: 011-44-1332-242424; fax: 011-44-1332-245418; or email 
from <a href="http://www.rolls-royce.com/contact/civil_team.jsp">http://www.rolls-royce.com/contact/civil_team.jsp</a>. You may review 
copies of the referenced service information at the FAA, Engine & 
Propeller Directorate, 12 New England Executive Park, Burlington, MA 
01803. For information on the availability of this material at the FAA, 
call 781-238-7121.

Examining the AD Docket

    You may examine the AD docket on the Internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a>; or in person at the Docket Management Facility 
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 address for the 
Docket Office (phone: 800-647-5527) is Document Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Alan Strom, Aerospace Engineer, Engine 
Certification Office, FAA, 12 New England Executive Park, Burlington, 
MA; phone: 781-238-7143; fax: 781-238-7199; email: <a href="/cdn-cgi/l/email-protection#d3b2bfb2bdfda0a7a1bcbe93b5b2b2fdb4bca5"><span class="__cf_email__" data-cfemail="f59499949bdb8681879a98b5939494db929a83">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a supplemental notice of proposed rulemaking (SNPRM) to 
amend 14 CFR part 39 to supersede AD 2008-18-08, Amendment 39-15665 (73 
FR 52201, September 9, 2008). That AD applies to the specified 
products. The SNPRM published in the Federal Register on January 20, 
2012 (77 FR 2932). The original NPRM (76 FR 64283, October 18, 2011) 
proposed to continue to require initial inspections, add additional 
inspections, and an optional terminating action. The SNPRM proposed to 
continue to require initial inspections, add additional inspections, 
and a mandatory terminating action.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
and the FAA's response to each comment.

Request To Correct the Type of Inspection Called Out

    One commenter, Rolls-Royce plc, requested that we change ``Since we 
issued that NPRM, RR has ceased efforts to develop an on-wing ECI'' to 
``Since we issued that NPRM, RR has ceased efforts to develop an on-
wing ultrasonic inspection.'' The commenter stated that they were 
developing an ultrasonic inspection, not an ECI.
    We agree that we called out the wrong type of inspection in that 
part of the SNPRM preamble. However, that information is not repeated 
in the final rule. We did not change the AD.

Request To Correct Reference Errors

    Two commenters, The Boeing Company and Rolls-Royce plc, requested 
that we change the service bulletin number in paragraph (k)(2)(iii), 
from RR Alert Service Bulletin (ASB) No. RB.211-72-AG401, Revision 2, 
dated July 5, 2011, to RR ASB No. RB.211-72-AG402, Revision 1, dated 
January 11, 2011. They also requested that we correct the paragraph 
(j)(1) to (j)(2) in that same paragraph.
    We partially agree. We agree that we misnumbered the service 
bulletins. We do not agree to correct them because we deleted paragraph 
(k)(2)(iii) from the final AD.

Request To Clarify That Re-Balancing Eliminates the Requirement for All 
Repetitive Inspections

    Rolls-Royce plc requested that we clarify that re-balancing 
eliminates the requirement for all repetitive inspections.
    We agree. We changed the AD so that the mandatory terminating 
action eliminates the requirements for both on-wing and in-shop 
repetitive inspections.

Request for Clarification of Inspections Acceptable for Use

    American Airlines requested that we make it clear that the 
inspections required in paragraph 2(f)(1) of the SNPRM are acceptable 
for use whether the engine is on-wing (installed on an airplane) or in-
shop, but not during maintenance defined as a shop visit by the AD. 
American also recommended that we re-arrange the inspections in 
paragraphs (f)(1) and (f)(2) so that they are aligned with on-wing and 
off-wing maintenance activities.
    We agree. We clarified the AD by eliminating the headings of ``On-
Wing Inspections'' and ``In-Shop Inspections'' from paragraphs (f)(1), 
(f)(2), (g)(1), and (g)(2) of the AD. We also re-numbered the sub-
paragraphs under paragraph (f), to (1), (2) and (3), without sub-
headings. We also re-numbered the sub-paragraphs under paragraph (g) to 
(1), (2) and (3), without sub-headings.

Request To Delete the Re-Balance Requirement

    American Airlines requested that in the Mandatory Terminating 
Action paragraph (j) of the SNPRM, we delete the requirement to re-
balance the engines in accordance with ASBs No. RB.211-72-AG401 and No. 
RB.211-72-AG402. Instead, require inspection of the IP compressor rear 
shaft balance land, prohibit re-installation of balance weights on the 
IP compressor rear shaft balance land, simplify paragraph (k) to 
combine the previous credit inspection paragraphs, and delete the re-
balancing paragraph.
    The commenter stated that removal of the unsafe condition is 
accomplished by removal of the IP compressor balance weights from the 
rear balance land, which stops the fretting that causes the compressor 
rear shaft to crack.

[[Page 31177]]

    We partially agree. We agree with eliminating the requirement to 
re-balance the engine in accordance with ASBs No. RB.211-72-AG401 and 
No. RB.211-72-AG402, and removing the associated previous credit 
paragraphs because permanently removing the existing balance weights 
from the IP compressor rotor rear shaft balance land eliminates the 
unsafe condition. Accordingly, we changed the AD by eliminating the 
requirement to re-balance the engine in accordance with ASBs No. 
RB.211-72-AG401 and No. RB.211-72-AG402. We do not agree with further 
simplifying paragraph (k) because we maintained all of the sub-
paragraphs for paragraph (f) and (g).
    We also added the following Prohibition Statement: ``Once you have 
accomplished paragraphs (j)(1) or (j)(2) of this AD, do not re-install 
balance weights on the compressor rear shaft balance land.''
    We also deleted previous credit for re-balancing paragraphs 
(k)(1)(iii) and (k)(2)(iii) from the AD.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect about 136 engines installed on 
airplanes of U.S. registry. We also estimate that it will take about 
3.5 work-hours per engine to perform the on-wing/in-shop visual 
inspections, about 2.5 work-hours per engine to perform the in-shop 
eddy current inspections, and about 8 work-hours to rebalance the IP 
compressor. The average labor rate is $85 per work-hour. Based on these 
figures, we estimate the total cost of the AD to U.S. operators to be 
$470,696.

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),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA 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 removing airworthiness directive (AD) 
2008-18-08, Amendment 39-15665 (73 FR 52201, September 9, 2008), and 
adding the following new AD:

2012-10-12 Rolls-Royce plc: Amendment 39-17061; Docket No. FAA-2007-
28059; Directorate Identifier 2007-NE-13-AD.

(a) Effective Date

    This AD is effective June 29, 2012.

(b) Affected ADs

    This AD supersedes AD 2008-18-08, Amendment 39-15665, (73 FR 
52201, September 9, 2008).

(c) Applicability

    This AD applies to Rolls-Royce plc (RR) RB211-Trent 553-61, 
553A2-61, 556-61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61, 
768-60, 772-60, 772B-60, 875-17, 877-17, 884-17, 884B-17, 892-17, 
892B-17, and 895-17 turbofan engines.

(d) Unsafe Condition

    This AD was prompted by additional cracking on RB211-Trent 700 
and RB211-Trent 800 IP compressor rotor shafts found since the 
existing AD 2008-18-08, Amendment 39-15665, (73 FR 52201, September 
9, 2008) was issued. We are issuing this AD to detect cracking on 
the IP compressor rotor rear balance land. IP compressor rotor rear 
balance land cracking can lead to uncontained failure of the rotor 
and damage to the airplane.

(e) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(f) RB211-Trent 700 Series Engines--Rear Balance Land Inspections

    (1) Within 625 cycles-in-service (CIS) after the effective date 
of this AD, borescope inspect the IP compressor rotor shaft rear 
balance land. Use RB211 Trent 700 Series Propulsion System Non-
Modification Alert Service Bulletin (NMASB) No. RB.211-72-AG270, 
Revision 4, dated March 21, 2011, sections 3.A.(2)(a) through 
3.A.(2)(c) and 3.A.(3)(a) through 3.A.(3)(c), or 3.B.(2)(a) through 
3.B.(2)(c) and 3.B.(4)(a) through 3.B.(4)(c), to do the inspection.
    (2) Thereafter, repeat the inspection within every 625 cycles-
since-last inspection (CSLI). You may count CSLI from the last 
borescope inspection or the last eddy current inspection (ECI), 
whichever has occurred last.
    (3) At each shop visit after the effective date of this AD, 
perform an ECI and visually inspect the IP compressor rotor rear 
shaft balance land, and visually inspect the balance weights. Use 
RB211 Trent 700 and 800 Series Propulsion Systems NMASB No. RB.211-
72-AG085, Revision 2, dated July 7, 2011, sections 3.A. through 
3.D.(3)(b)(v), except paragraphs 3.D.(3)(a)(ii) and 3.D.(3)(b)(iii), 
to do the inspections.

(g) RB211-Trent 800 Series Engines--Rear Balance Land Inspections

    (1) Within 475 CIS after the effective date of this AD, 
borescope inspect the IP compressor rotor shaft rear balance land. 
Use RB211 Trent 800 Series Propulsion System NMASB No. RB.211-72-
AG264, Revision 5, dated March 21, 2011, sections 3.A.(2)(b) through 
3.A.(2)(c) and 3.A.(3)(a) through 3.A.(3)(c), or 3.B.(2)(a) through 
3.B.(2)(c) and 3.B.(4)(a) through 3.B.(4)(c), to do the inspection.
    (2) Thereafter, repeat the inspection within every 475 CSLI. You 
may count CSLI from the last borescope inspection or the last ECI, 
whichever has occurred last.
    (3) At each shop visit, perform an ECI and visually inspect the 
IP compressor rotor rear shaft balance land, and visually inspect 
the balance weights. Use RB211 Trent 700 and 800 Series Propulsion 
Systems NMASB No.

[[Page 31178]]

RB.211-72-AG085, Revision 2, dated July 7, 2011, sections 3.A. 
through 3.D.(3)(b)(v), except paragraphs 3.D.(3)(a)(ii) and 
3.D.(3)(b)(iii), to do the inspections.

(h) RB211-Trent 500 Series Engines--In-Shop Rear Balance Land 
Inspections

    At each shop visit, perform an ECI of the IP compressor rotor 
shaft and visually inspect the balance weights. Use RB211 Trent 500 
Series Propulsion System NMASB No. RB.211-72-AF260, Revision 5, 
dated July 7, 2011 sections 3.A. through 3.B.(3)(a)(iii) to do the 
visual inspection, or RB211 Trent 500 and 900 Series Propulsion 
Systems Non-Modification Service Bulletin (NMSB) No. RB.211-72-G448, 
Revision 3, dated July 7, 2011 section 3.D.(1) through 3.D.(14) to 
do the ECI.

(i) Definition

    For the purposes of this AD, a shop visit is defined as 
introduction of an engine into a shop, and disassembly sufficient to 
expose the IP compressor module rear face.

(j) Mandatory Terminating Action for RB211-Trent 700 and RB211-Trent 
800 Engines

    (1) Perform mandatory terminating action to the in-shop 
repetitive inspections in paragraph (f)(2) and (f)(3) of this AD. At 
the next shop visit in which any level of inspection or strip is 
scheduled to be carried out on the IP compressor, modify RB211-Trent 
700 engines by removing the existing IP compressor balance weights.
    (2) Perform mandatory terminating action to the in-shop 
repetitive inspections in paragraph (g)(2) and (g)(3) of this AD. At 
the next shop visit in which any level of inspection or strip is 
scheduled to be carried out on the IP compressor, modify RB211-Trent 
800 engines by removing the existing IP compressor balance weights.
    (3) Once you have accomplished paragraph (j)(1) or (j)(2) of 
this AD, do not re-install balance weights on the IP compressor rear 
shaft balance land.

(k) Credit for Previous Actions

    (1) For RB211-Trent 700 series engines:
    (i) If you borescope inspected your RB211-Trent 700 series 
engine using RB211 Trent 700 Series Propulsion System NMASB No. 
RB.211-72-AG270, Revision 1, dated December 14, 2009, or Revision 2, 
dated December 21, 2010, or Revision 3, dated February 25, 2011, 
before the effective date of this AD, you have satisfied the 
requirements of paragraph f(1) of this AD.
    (ii) If you performed the ECI and visual inspection of your 
RB211-Trent 700 series engines using RB211 Trent 700 and 800 Series 
Propulsion Systems NMASB No. RB.211-72-AG085, Revision 1, dated 
September 27, 2010, before the effective date of this AD, you have 
satisfied the ECI and visual inspections required by paragraph 
(f)(3) of this AD.
    (2) For RB211-Trent 800 series engines:
    (i) If you borescope inspected your RB211-Trent 800 series 
engine using RB211 Trent 800 Series Propulsion System NMASB No. 
RB.211-72-AG264, Revision 3, dated December 21, 2010, or Revision 4, 
dated February 25, 2011, before the effective date of this AD, you 
have satisfied the requirements of paragraph (g)(1) of this AD.
    (ii) If you performed the ECI and visual inspection of your 
RB211-Trent 800 series engines using RB211 Trent 700 and 800 Series 
Propulsion Systems NMASB No. RB.211-72-AG085, Revision 1, dated 
September 27, 2010, before the effective date of this AD, you have 
satisfied the ECI and visual inspections required by paragraph 
(g)(3) of this AD.
    (3) For RB211-Trent 500 series engines:
    (i) If you performed the ECI of your RB211-Trent 500 series 
engines using RB211 Trent 500 Series Propulsion System NMASB No. 
RB.211-72-AF260, Revision 4, dated July 28, 2009, before the 
effective date of this AD, you have satisfied the ECIs required by 
paragraph (h) of this AD.
    (ii) If you performed the in-shop visual inspection of your 
RB211-Trent 500 series engines using RB211 Trent 500 and 900 Series 
Propulsion Systems NMSB No. RB.211-72-G448, Revision 2, dated 
December 23, 2010, before the effective date of this AD, you have 
satisfied the in-shop visual inspections required by paragraph (h) 
of this AD.

(l) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, may approve AMOCs 
for this AD. Use the procedures in 14 CFR 39.19 to make your 
request.

(m) Related Information

    (1) For more information about this AD, contact Alan Strom, 
Aerospace Engineer, Engine Certification Office, FAA, 12 New England 
Executive Park, Burlington, MA; phone: 781-238-7143; fax: 781-238-
7199; email: <a href="/cdn-cgi/l/email-protection#d6b7bab7b8f8a5a2a4b9bb96b0b7b7f8b1b9a0"><span class="__cf_email__" data-cfemail="3d5c515c53134e494f52507d5b5c5c135a524b">[email&#160;protected]</span></a>.
    (2) European Aviation Safety Agency AD 2011-0221, dated November 
14, 2011, also pertains to the subject of this AD.

(n) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) under 5 U.S.C. 552(a) and 1 CFR 
part 51 of the following service information.
    (2) You must use the following service information to do the 
actions required by this AD, unless the AD specifies otherwise.
    (i) Rolls-Royce plc RB211 Trent 700 Series Propulsion System 
Non-Modification Alert Service Bulletin No. RB.211-72-AG270, 
Revision 4, dated March 21, 2011.
    (ii) Rolls-Royce plc RB211 Trent 700 and 800 Series Propulsion 
Systems Non-Modification Alert Service Bulletin No. RB.211-72-AG085, 
Revision 2, dated July 7, 2011.
    (iii) Rolls-Royce plc RB211 Trent 800 Series Propulsion System 
Non-Modification Alert Service Bulletin No. RB.211-72-AG264, 
Revision 5, dated March 21, 2011.
    (iv) Rolls-Royce plc RB211 Trent 500 Series Propulsion System 
Non-Modification Alert Service Bulletin No. RB.211-72-AF260, 
Revision 5, dated July 7, 2011.
    (v) Rolls-Royce plc RB211 Trent 500 and 900 Series Propulsion 
Systems Non-Modification Service Bulletin No. RB.211-72-G448, 
Revision 3, dated July 7, 2011.
    (3) For service information identified in this AD, contact 
Rolls-Royce plc, Corporate Communications, P.O. Box 31, Derby, 
England, DE248BJ; phone: 011-44-1332-242424; fax: 011-44-1332-
245418; or email from <a href="http://www.rolls-royce.com/contact/civil_team.jsp">http://www.rolls-royce.com/contact/civil_team.jsp</a>.
    (4) You may review copies of the referenced service information 
at the FAA, Engine & Propeller Directorate, 12 New England Executive 
Park, Burlington, MA 01803. For information on the availability of 
this material at the FAA, call 781-238-7125.
    (5) You may also review copies of the service information that 
is IBR 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: <a href="http://www.archives.gov/federal-register/cfr/ibr_locations.html">http://www.archives.gov/federal-register/cfr/ibr_locations.html</a>.

    Issued in Burlington, Massachusetts, on May 15, 2012.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-12726 Filed 5-24-12; 8:45 am]
BILLING CODE 4910-13-P

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