[Federal Register Volume 76, Number 85 (Tuesday, May 3, 2011)]
[Rules and Regulations]
[Pages 24793-24796]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-10517]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0562; Directorate Identifier 2009-NE-29-AD; 
Amendment 39-16669; AD 2011-09-07]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce plc (RR) RB211-524 Series 
and RB211 Trent 500, 700, and 800 Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for the 
products listed above. This AD results from mandatory continuing 
airworthiness information (MCAI) issued by an aviation authority of 
another country to identify and correct an unsafe condition on an 
aviation product. The MCAI describes the unsafe condition as:

    During manufacture of a number of HP Compressor Stage 1 and 2 
discs with axial dovetail slots, anomalies at the disc post corners 
have been found. Fatigue crack initiation and subsequent crack 
propagation at the disc post may result in release of two blades and 
the disc post. This may potentially be beyond the containment 
capabilities of the engine casings. Thus, these anomalies present at 
the disc posts constitute a potentially unsafe condition.

    We are issuing this AD to detect cracks in the high-pressure 
compressor (HPC) Stage 1 and 2 disc posts, which could result in 
failure of the disc post and release of HPC blades, release of 
uncontained engine debris, and damage to the airplane.

DATES: This AD becomes effective June 7, 2011. The Director of the 
Federal Register approved the incorporation by reference of certain 
publications listed in this AD as of June 7, 2011.

ADDRESSES: The Docket Operations office is located at Docket Management

[[Page 24794]]

Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

FOR FURTHER INFORMATION CONTACT: Alan Strom, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (781) 238-7143; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM was published in the Federal Register on June 15, 2010 (75 FR 
33738). That NPRM proposed to correct an unsafe condition for the 
specified products. The MCAI states that:

    During manufacture of a number of HP Compressor Stage 1 and 2 
discs with axial dovetail slots, anomalies at the disc post corners 
have been found. Fatigue crack initiation and subsequent crack 
propagation at the disc post may result in release of two blades and 
the disc post. This may potentially be beyond the containment 
capabilities of the engine casings. Thus, these anomalies present at 
the disc posts constitute a potentially unsafe condition.
    For the reasons described above, this AD requires repetitive 
inspections of the axial dovetail slots and follow-on corrective 
action, depending on findings.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received.

Request To Change the Definition of a Shop Visit

    Five commenters request that we change the criteria for carrying 
out the inspections to be consistent with the European Aviation Safety 
Agency (EASA) AD. The commenters ask that we require performing the 
inspections at the first shop visit after accumulating 1,000 hours-
since-new (HSN) and whenever a Level 3 (Refurbishment) or Level 4 
(Overhaul) shop visit occurs. The commenters feel that requiring the 
inspections any time a major flange is separated would result in more 
inspections than required by the EASA AD. Some of the inspections would 
cost significantly more than what is estimated in the Costs of 
Compliance section of the proposed AD.
    We partially agree. We agree that the current wording would result 
in more inspections than required by the EASA AD, and some of the 
inspections would cost significantly more than what we estimated in the 
Costs of Compliance section of the proposed AD. We do not agree with 
using the Level 3 or Level 4 criteria as a definition of ``engine shop 
visit'' for the purpose of this AD. The definitions of Level 3 and 
Level 4 are not specific enough to ensure the inspections are conducted 
frequently enough to prevent the unsafe condition. We changed the 
definition of shop visit in paragraph (f) of the proposed AD from ``For 
* * * an ``engine shop visit'' is the induction of an engine into the 
shop for maintenance involving the separation of pairs of major mating 
engine flanges, * * *'' to ``For * * * an ``engine shop visit'' is 
whenever the engine high-pressure compressor module is separated from 
the intermediate case.''

Request To Change the Summary of the Proposed AD

    One commenter, RR, asks us to consider changing the Summary from 
``Thus, these anomalies present at the disc posts constitute a 
potentially unsafe condition'' to ``Thus, if these anomalies are 
present at the disc posts, they constitute a potentially unsafe 
condition.'' The commenter believes that the MCAI description implies 
that all discs have the anomalies in question. The AD does not assume 
that to be true.
    We don't agree. The second paragraph of the Summary quotes the EASA 
AD. We did not change the AD.

Request To Correct a Disc Part Number

    The same commenter asks us to change paragraph (c)(1) part number 
(P/N) ``FK20195'' to ``FW20195.'' The commenter states that the NPRM 
contains a typographical error.
    We agree. We changed the part number in paragraph (c)(1) of the 
proposed AD from ``FK20195'' to ``FW20195.''

Request To Change the Unsafe Condition Statement

    The same commenter asks us to change the unsafe condition statement 
in the Summary and in paragraph (d) of the proposed AD from ``* * * 
failure of the disc post, which could result in failure of the disc 
post and HPC blades, release * * * airplane'' to ``* * * failure of the 
disc post, resulting in release of HPC blades, release * * * 
airplane.'' The commenter states the NPRM implies that high-pressure 
compressor blades may themselves fail, when in fact they are released 
as a result of disk post failure.
    We agree. We changed the unsafe condition statement in the Summary 
and in paragraph (d) of the proposed AD to ``which could result in 
failure of the disc post, release of HPC blades, release of uncontained 
debris, * * * airplane.''

Request To Ensure the Disc is Cleaned before Inspection

    The same commenter asks us to change paragraph (e)(1) of the 
proposed AD from ``Perform a * * * later. Use paragraph 3.E.(1) through 
3.E.(10)(i) * * * inspections'' to ``Clean and perform * * * later. Use 
paragraph 3.A through 3.E.(10)(i) * * * inspections.'' The commenter 
believes the change will ensure adequate cleaning before inspection, 
which is essential to make sure the small cracks are visible.
    We agree. Because the corrective action is looking for small cracks 
underneath a dry film lubricant coating, the cleaning procedure prior 
to fluorescent penetrant inspection (FPI) is critical to the corrective 
action. We changed paragraph (e)(1) of the proposed AD to ``Clean and 
perform * * * later. Use paragraph 3.A through 3.E.(11) * * * 
inspections.'' We also added paragraph 3.E.(11) to ensure that the 
blades will be re-coated prior to re-installation.

Request To Change Nomenclature of HPC Rotor Shaft

    One commenter, Hawaiian Airlines, asks us to change ``HPC rotor 
shaft'' to ``HP compressor drum.'' The commenter states that the HPC 
drum in the Trent 700 engine is a six stage rotor and is referred to as 
the ``HPC rotor shaft.'' Since each engine model has different 
nomenclature, they request that we use a common name when we refer to 
the subject part such as ``HP compressor Drum.'' The commenter believes 
that this will ensure a common understanding of the parts involved.
    We don't agree. While the service bulletin uses the term ``HPC 
drum,'' the AD consistently refers to the HPC disks by stage number.

Conclusion

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

Costs of Compliance

    Based on the service information, we estimate that this AD would 
affect about 371 products of U.S. registry. We also estimate that it 
would take about 20 work-hours per product to comply with this AD. The 
average labor rate is $85 per work-hour. No parts would be

[[Page 24795]]

required per product. Based on these figures, we estimate the cost of 
the AD on U.S. operators to be $630,700.

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 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 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 regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket.

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 (phone (800) 647-5527) is provided in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

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 adding the following new AD:

2011-09-07 Rolls-Royce plc (RR): Amendment 39-16669. Docket No. FAA-
2010-0562; Directorate Identifier 2009-NE-29-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective June 7, 
2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to RR model RB211-524G2-T-19, -524G3-T-19, -
524H-T-36, and -524H2-T-19; and RB211 Trent 553-61, 553A2-61, 556-
61, 556A2-61, 556B-61, 556B2-61, 560-61, 560A2-61; RB211 Trent 768-
60, 772-60, 772B-60; and RB211 Trent 875-17, 877-17, 884-17, 884B-
17, 892-17, 892B-17, and 895-17 turbofan engines that have a high-
pressure (HP) compressor stage 1 to 4 rotor disc with a part number 
(P/N) listed in Table 1 of this AD. These engines are installed on, 
but not limited to, Boeing 747, 767, and 777 series airplanes and 
Airbus A330 and A340 series airplanes.

 Table 1--Affected HP Compressor Stage 1 to 4 Rotor Disc P/Ns by Engine
                                  Model
------------------------------------------------------------------------
                                            HP compressor stage 1 to 4
              Engine model                        rotor disc P/N
------------------------------------------------------------------------
(1) RB211-524G2-T-19, -524G3-T-19, -     FW20195, FK25502, or FW23711.
 524H-T-36, and -524H2-T-19.
(2) RB211 Trent 553-61, 553A2-61, 556-   FK30524.
 61, 556A2-61, 556B-61, 556B2-61, 560-
 61, and 560A2-61.
(3) RB211 Trent 768-60, 772-60, and      FK22745, FK24031, FK26185,
 772B-60.                                 FK23313, FK25502, FK32129,
                                          FW20195, FW20196, FW20197,
                                          FW20638, or FW23711.
(4) RB211 Trent 875-17, 877-17, 884-17,  FK24009, FK26167, FK32580,
 884B-17, 892-17, 892B-17, and 895-17.    FW11590, or FW61622.
------------------------------------------------------------------------

Reason

    (d) This AD results from reports that:
    During manufacture of a number of HP Compressor Stage 1 and 2 
discs with axial dovetail slots, anomalies at the disc post corners 
have been found. Fatigue crack initiation and subsequent crack 
propagation at the disc post may result in release of two blades and 
the disc post. This may potentially be beyond the containment 
capabilities of the engine casings. Thus, these anomalies present at 
the disc posts constitute a potentially unsafe condition.

We are issuing this AD to detect cracks in the high-pressure 
compressor (HPC) Stage 1 and 2 disc posts, which could result in 
failure of the disc post and release of HPC blades, release of 
uncontained engine debris, and damage to the airplane.

Actions and Compliance

    (e) Unless already done, do the following actions.
    (1) Clean and perform a fluorescent penetrant inspection of the 
HP compressor stage 1 to 4 rotor discs at the first shop visit after 
accumulating 1000 cycles since new on the stage 1 to 4 rotor disks 
or at the next shop visit after the effective date of this AD, 
whichever occurs later. Use paragraph 3.A through 3.E.(11) of the 
Accomplishment Instructions of Rolls-Royce Alert Service Bulletin 
(ASB) RB.211-72-AF964, Revision 1, dated June 6, 2008 to do the 
inspections.
    (2) Thereafter at every engine shop visit, perform the 
inspection specified by paragraph (e)(1) of this AD.

Definitions

    (f) For the purpose of this AD, an ``engine shop visit'' is 
whenever the engine high-pressure compressor module is separated 
from the intermediate case.

Other FAA AD Provisions

    (g) Alternative Methods of Compliance (AMOCs): The Manager, 
Engine Certification Office, FAA, has the authority to approve

[[Page 24796]]

AMOCs for this AD, if requested using the procedures found in 14 CFR 
39.19.

Related Information

    (h) See European Aviation Safety Agency Airworthiness Directive 
2009-0073R1, dated April 8, 2009, for related information.
    (i) Contact Alan Strom, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: [email protected]; 
telephone (781) 238-7143; fax (781) 238-7199, for more information 
about this AD.

Material Incorporated by Reference

    (j) You must use Rolls-Royce Alert Service Bulletin RB.211-72-
AF964, Revision 1, dated June 6, 2008, to do the actions required by 
this AD, unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of this service information under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) For service information identified in this AD, contact 
Rolls-Royce plc, P.O. Box 31, Derby, DE24 8BJ, United Kingdom; 
phone: 011 44 1332 242424, fax: 011 44 1332 249936; e-mail: 
royce.com">tech.help@rolls-royce.com.
    (3) 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 April 12, 2011.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2011-10517 Filed 5-2-11; 8:45 am]
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