Airworthiness Directives; Rolls-Royce plc RB211-Trent 800 Series Turbofan Engines

[Federal Register Volume 76, Number 85 (Tuesday, May 3, 2011)]
[Rules and Regulations]
[Pages 24796-24798]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-10520]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1165; Directorate Identifier 2008-NE-38-AD; 
Amendment 39-16685; AD 2011-10-04]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce plc RB211-Trent 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 high-pressure (HP) compressor stage 1 
discs, a small number of parts have been rejected due to a machining 
defect that was found during inspection. Analysis of the possibility 
of less severe examples having been undetected and passed into 
service has concluded that action is required to reduce the risk of 
failure. It was therefore necessary to reduce the life limit.

The HP compressor stage 1 disc is part of the HP compressor stage 1-4 
shaft, part number (P/N) FK32580. We are issuing this AD to prevent 
failure of the HP compressor stage 1 disc, uncontained engine failure, 
and damage to the airplane.

DATES: This AD becomes effective June 7, 2011.

ADDRESSES: The Docket Operations office is located at Docket Management 
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 & 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) and a supplemental 
notice of proposed rulemaking (SNPRM) 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 February 18, 2009 (74 FR 7563) and 
that SNPRM was published in the Federal Register on October 4, 2010 (75 
FR 61114). That SNPRM proposed to correct an unsafe condition for the 
specified products. The MCAI states that:

    During manufacture of high-pressure (HP) compressor stage 1 
discs, a small number of parts have been rejected due to a machining 
defect that was found during inspection. Analysis of the possibility 
of less severe examples having been undetected and passed into 
service has concluded that action is required to reduce the risk of 
failure. It was therefore necessary to reduce the life limit.

    The HP compressor stage 1 disc is part of the HP compressor stage 
1-4 shaft, P/N FK32580. Since we issued the original NPRM on February 
10, 2009 (74 FR 7563, February 18, 2009), EASA issued AD 2010-0087, 
dated May 5, 2010 (corrected May 6, 2010), which retains certain 
requirements of superseded EASA AD 2008-0099, and imposes more 
restrictive life limits in the Heavy Flight Profile Parts. You may 
obtain further information by examining the MCAI in the AD docket.

Comments

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

Request To Revise the Compliance Times

    Four commenters, American Airlines, Delta Airlines, Rolls-Royce 
plc, and The Boeing Company, request that we revise the compliance 
times to be consistent with the service bulletin and the airworthiness 
limitations section (ALS) of the engine manual. Doing this would 
account for the later AD release date and for the entire Trent 800 
series fleet instead of just certain US operators' expected cyclic 
usage. The commenters state that the proposed requirements would have a 
severe adverse economic impact to operators relative to the service 
bulletin requirements. The simplified compliance requirements in the 
SNPRM relative to the service bulletin requirements, may not accurately 
reflect the risk of an uncontained event, and are confusing.
    We do not agree. The requirements in the SNPRM were developed to 
minimize the risk of uncontained disc failure, based on the age of the 
parts in the field at the time the SNPRM was issued. The service 
bulletin requirements were developed at a time when the age of the 
parts in service was lower than when the SNPRM was issued. Because the 
risk of failure increases as the age of the parts in the field 
increase, any revision to the requirements of the SNPRM would again 
have to take the increased age of the parts in service into account. As 
such, an analysis would result in removal requirements more stringent 
than the requirements in the SNPRM, and a follow-on NPRM would be 
required. Therefore, we determined that it is in the public interest to 
keep the removal requirements the same as published in the SNPRM. We 
did not change the AD.

Request for Clarity and Interpretation

    Delta Airlines states that it would be helpful if we could provide 
some clarity in the AD as to how an operator should interpret the 
differing information between the AD, the ALS of the Rolls-Royce Time 
Limits Manual, and the service bulletin. The commenter is concerned 
that there will be three locations where the life limit of the

[[Page 24797]]

shaft, P/N FK32580, is specified, and all three have different data.
    We do not agree. The AD and the ALS take precedence over the 
service bulletin. Operators must comply with the AD and the ALS. We did 
not change the AD.

Question on Reworked Part

    Delta Airlines asks for clarification as to whether a part reworked 
from P/N FK32580 to FW61622, is still required to be removed in 
accordance with paragraphs (e)(1) and (e)(2) of the AD. The commenter 
is unsure if a reworked part can be returned to service under the life 
limit of the new part number.
    The AD applies only to P/N FK32580. If the part is reworked to a 
different P/N, the requirements of the new P/N would apply. We did not 
change the AD.

Request To Use the Service Bulletin Method

    American Airlines requests that we revise the AD to use the service 
bulletin method of determining the number of cycles before removal is 
required; specifically, based on a date before the effective date of 
the AD. The commenter states that the simplified compliance in the 
SNPRM would result in early engine removal and a cumulative loss of 
about eleven engine-years of useful service to American Airlines.
    We do not agree. The compliance thresholds in the AD are a function 
of usage, which is not directly related to calendar dates. We did not 
change the AD.

Request To Update Contact Information

    Rolls-Royce plc requests that we update their contact information 
in the AD to: Rolls-Royce plc, Corporate Communications, P.O. Box 31, 
Derby, England, DE248BJ, telephone: 011-44-1332-242424; fax: 011-44-
1332-245418, or e-mail: http://www.rolls-royce.com/contact/civil_team.jsp.
    We agree and changed the AD.

Conclusion

    We reviewed the available data and determined that air safety and 
the public interest require adopting the AD with the change described 
previously.

Differences Between This AD and the MCAI

    We have reviewed the MCAI and, in general, agree with its 
substance. But we have found it necessary to not incorporate the June 
4, 2008 compliance date which is in EASA AD 2010-0087, dated May 5, 
2010 (corrected May 6, 2010). We updated the compliance times in the AD 
based on a more recent assessment of the unsafe condition.

Costs of Compliance

    Based on the service information, we estimate that this AD will 
affect about 78 products of U.S. registry. Required parts will cost 
about $15,095 per product. We estimate that no additional labor costs 
would be incurred to perform the actions, as we anticipate that the 
removal from service of the HP compressor stage 1-4 shafts will occur 
while the engine is inducted into the shop for routine maintenance. 
Based on these figures, we estimate the cost of the AD on U.S. 
operators to be $1,177,410.

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:

2011-10-04 Rolls-Royce plc: Amendment 39-16685; Docket No. FAA-2008-
1165; Directorate Identifier 2008-NE-38-AD.

Effective Date

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

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Rolls-Royce plc models RB211-Trent 875-
17, -Trent 877-17, -Trent 884-17, -Trent 884B-17, -Trent 892-17, -
Trent 892B-17, and -Trent 895-17 turbofan engines, with high-
pressure (HP) compressor stage 1-4 shafts, part number (P/N) 
FK32580, installed.

Reason

    (d) 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. European Aviation Safety Agency (EASA) AD 2010-0087, dated 
May 5, 2010 (corrected May 6, 2010) states the unsafe condition is 
as follows:
    During manufacture of high-pressure (HP) compressor stage 1 
discs, a small number of parts have been rejected due to a machining 
defect that was found during inspection. Analysis of the possibility 
of less severe examples having been undetected and passed into 
service has concluded that action is required to reduce the risk of 
failure. It was therefore necessary to reduce the life limit.


[[Page 24798]]


The HP compressor stage 1 disc is part of the HP compressor stage 1-
4 shaft, P/N FK32580. We are issuing this AD to prevent failure of 
the HP compressor stage 1 disc, uncontained engine failure, and 
damage to the airplane.

Actions and Compliance

    (e) Unless already done, do the following actions.

Multiple Flight Profile Monitoring Parts

    (1) For RB211-Trent 800 series engines being monitored by 
``Multiple Flight Profile Monitoring,'' remove the HP compressor 
stage 1-4 shaft, P/N FK32580, before accumulating 5,580 standard 
duty cycles (SDC) since-new or within 960 SDC from the effective 
date of this AD, whichever occurs later.

Heavy Flight Profile Parts

    (2) For RB211-Trent 800 series engines being monitored by 
``Heavy Flight Profile,'' remove the HP compressor stage 1-4 shaft, 
P/N FK32580, before accumulating 5,280 flight cycles since new or 
within 860 flight cycles from the effective data of this AD, 
whichever occurs later.

FAA Differences

    (f) We have found it necessary to not incorporate the June 4, 
2008 compliance date which is in EASA AD 2010-0087, dated May 5, 
2010 (corrected May 6, 2010). We also updated the compliance times 
in the AD based on a more recent assessment of the unsafe condition.

Alternative Methods of Compliance (AMOCs)

    (g) The Manager, Engine Certification Office, FAA, has the 
authority to approve AMOCs for this AD, if requested using the 
procedures found in 14 CFR 39.19.

Related Information

    (h) Refer to EASA Airworthiness Directive 2010-0087, dated May 
5, 2010 (corrected May 6, 2010), and Rolls-Royce plc Alert Service 
Bulletin No. RB.211-72-AF825, Revision 3, dated August 25, 2009 for 
related information. Contact Rolls-Royce plc, Corporate 
Communications, P.O. Box 31, Derby, England, DE248BJ, telephone: 
011-44-1332-242424; fax: 011-44-1332-245418; or e-mail via: http://www.rolls-royce.com/contact/civil_team.jsp, for a copy of this 
service information.
    (i) Contact Alan Strom, Aerospace Engineer, Engine Certification 
Office, FAA, Engine & 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.

    Issued in Burlington, Massachusetts, on April 25, 2011.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2011-10520 Filed 5-2-11; 8:45 am]
BILLING CODE 4910-13-P

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