Airworthiness Directives; Rolls-Royce plc Turbofan Engines

[Federal Register Volume 78, Number 192 (Thursday, October 3, 2013)]
[Rules and Regulations]
[Pages 61171-61173]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-23452]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0029; Directorate Identifier 2013-NE-01-AD; 
Amendment 39-17599; AD 2013-19-17]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce plc 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 all 
Rolls-Royce plc (RR) RB211-535E4-B-37 series turbofan engines. This AD 
requires removal of affected parts using a drawdown plan. This AD was 
prompted by recalculating the lives of certain rotating life limited 
parts (LLPs) operated to certain flight profiles. We are issuing this 
AD to prevent the failure of rotating LLPs, which could result in 
uncontained failure of the engine and damage to the airplane.

DATES: This AD becomes effective November 7, 2013. The Director of the 
Federal Register approved the incorporation by reference of certain 
publications listed in this AD as of November 7, 2013.

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.

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 mandatory continuing 
airworthiness information (MCAI), 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.

FOR FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; phone: 781-238-7754; 
fax: 781-238-7199; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to the specified products. The 
NPRM was published in the Federal Register on April 5, 2013 (78 FR 
20509). The NPRM proposed to correct an unsafe condition for the 
specified products. The MCAI states:

    Flight Profiles (FP) define the limits of engine operation 
within which the engine will qualify for use of an associated set of 
Critical Parts life limits. The Rolls-Royce RB211-535E4-B-37 engine 
previously had only one such FP and associated set of life limits 
published in the applicable RR Time Limits Manual.
    However, a recent review of operational flight data has revealed 
that some engines may have been operated beyond the currently valid 
datum FP.
    Failure to account for the correct rate of fatigue damage 
associated with engine operation may lead to Critical Parts failure, 
possibly resulting in release of high energy debris, damage to the 
aeroplane and/or injury to occupants.

Comments

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

Agreement With the AD

    The Boeing Company expressed support for the NPRM (78 FR 20509, 
dated April 5, 2013).

Request To Be Less Specific About Service Bulletin Revision Level and 
Date

    Texas Aero Engine Service LLC, RR, and United Airlines (UAL) 
requested that we not include the revision level and date of RR Alert 
Non-Modification Service Bulletin (NMSB) No. RB.211-72-AG875, or that 
we add the words ``or later revision'' because service bulletins can be 
revised often.
    We disagree. RR Alert NMSB No. RB.211-72-AG875, dated December 13, 
2012, contains unique methods that require incorporation by reference, 
requiring that we specify revision level and date. We do not know how 
the NMSB may be revised in the future, and therefore cannot add the 
words ``or later revision.'' We did not change this AD.

Request To Change the Definition of Engine Shop Visit (ESV)

    RR and UAL requested that we change our definition of ESV in 
paragraph (g) of this AD by replacing the words ``separation of 
flanges'' with ``deblading of the affected rotor disc.'' They noted 
that our definition of ESV is not consistent with the instructions in 
RR Alert NMSB No. RB.211-72-AG875, dated December 13, 2012, which only 
applies when the rotor is debladed. Our ESV definition will result in 
the removal of parts earlier than would occur using the RR NMSB. RR 
noted that this is not necessary based on their risk assessment of a 
possible failure. In a subsequent comment, RR asked that the ESV 
definition be based on the deblading of the high pressure turbine disc 
since this better defines an engine refurbishment shop visit.
    We disagree. We defined ESV as the separation of a pair of major 
mating engine module flanges in order to satisfy our safety concerns 
while minimizing the impact to the public. The redefined, reduced 
cyclic life limits are needed to correct an unsafe condition. We have 
determined that corrective actions can be practicably implemented at 
next ESV and that these actions will provide an acceptable level of 
safety. We did not change this AD.

Request To Exempt an External Gearbox Removal From the ESV Definition

    RR requested that we clarify that the separation of a pair of major 
mating engine module flanges in paragraph (g) of this AD does not 
include the separation of an engine external gearbox from the engine, 
which would not constitute a refurbishment shop visit.
    We agree. We changed paragraph (g) of this AD to state: ``For the 
purpose of this AD, ESV is whenever engine maintenance performed prior 
to reinstallation requires the separation of a pair of major mating 
engine module flanges. Separation of flanges solely for the purpose of 
shipment without subsequent internal maintenance is not an ESV. 
Separation of the external gearbox engine mating flanges or removal of 
the external gearbox is also not classified as a shop visit.''

Request To Delay Implementation of Reduced Rotating Parts Life Limits

    American Air Lines (AAL) and RR asked that we revise or remove 
paragraph (e)(2) of this AD to eliminate the requirement to assign the 
reduced maximum approved lives within 30 days of the effective date of 
this AD and allow the current lives as published in

[[Page 61172]]

the Time Limits Manual (TLM) to remain in effect until November 30, 
2016. AAL stated that the AD requirement will cause problems for 
operator life limit tracking systems, causing confusion and possibly 
the grounding of aircraft. Operator life limit tracking systems prevent 
the operation of parts beyond their maximum approved lives.
    We disagree. Operating beyond the redefined, reduced cyclic life 
limits represents an unsafe condition. LLPs that exceed the reduced 
life limits should be removed from service as soon as practicable to 
correct an unsafe condition. We did not change this AD.

Request To Clarify Wording Regarding Compliance Date and Life Limits

    AAL and RR requested that we clarify wording in paragraph (e)(5) of 
this AD regarding removal of affected parts by the compliance date, and 
that the parts cannot exceed current life limits. One commenter stated 
that this paragraph could potentially allow parts to operate beyond 
both the current and reduced life limits.
    We partially agree. We agree that paragraph (e)(5) of this AD could 
be misinterpreted because we did not specify that paragraph (e)(4) of 
this AD applies to those engines which have an engine shop visit prior 
to reaching the reduced life.
    We do not agree that the compliance wording could potentially allow 
parts to operate beyond their current life limits because the life 
limits, as published in the TLM for RR RB211 engines, cannot be 
exceeded.
    We changed paragraph (e)(4) of this AD by inserting ``before 
reaching the part life assigned in paragraph (e)(2)''. The paragraph 
now reads: ``(4) After the effective date of this AD, for engines that 
incorporate an LP turbine disc stage 2, IP compressor rotor shaft 
(stage 1 to 6), HP compressor rear rotor shaft assembly, or HP turbine 
disc whose part life is defined by paragraph (e)(1) of this AD, that 
have an engine shop visit (ESV) before reaching the part life assigned 
in paragraph (e)(2) of this AD, remove each part from service before 
the part exceeds the part life assigned in paragraph (e)(2).''

Request To Change Compliance To Be Consistent With the RR NMSB

    AAL, RR, and UAL requested that we change the compliance to be 
consistent with RR Alert NMSB No. RB.211-72-AG875, dated December 13, 
2012. AAL noted that the risk assessment conducted by RR supports the 
continued use of the current life limits for parts not exposed during a 
shop visit, and demonstrated an acceptable level of safety. AAL further 
stated that the AD as proposed (78 FR 20509, April 5, 2013) will result 
in significant shop visit costs in comparison to the shop visit costs 
associated with the RR Alert NMSB.
    We disagree. The redefined, reduced cyclic life limits are needed 
to correct an unsafe condition. We have determined that corrective 
actions can be practicably implemented at next ESV and that these 
actions will provide an acceptable level of safety. We did not change 
this AD.

Request To Change Compliance Time

    UAL requested that we change the compliance time in paragraphs 
(e)(1) and (e)(2) of this AD from ``within 30 days'' to ``within 90 
days'' because for UAL's fleet of 137 engines, 30 days is too short of 
a compliance period.
    We disagree. The recommended timeframe for completion in RR Alert 
NMSB No. RB.211-72-AG875, dated December 13, 2012, was 6 weeks. The new 
lives of the rotating LLPs could have been recalculated starting from 
when the NMSB was issued. In addition, the effective date of this AD is 
35 days after the date of publication in the Federal Register, which 
provides additional time beyond the 30 days mandated in this AD. We did 
not change this AD.

Request To Change the Costs of Compliance

    AAL requested that we change the costs of compliance to include the 
labor costs associated with replacing the parts (i.e., engine 
disassembly costs). AAL states that the AD requires replacement of 
parts in modules that are not related to an engine removal cause, 
resulting in additional labor costs to access and replace those parts.
    We disagree. We consider the actual costs of this AD, which are 
associated with the prorated reduction in the lives of the LLPs. We do 
not consider the engine disassembly costs, which will vary depending on 
the category of the ESV. We did not change this AD.

Conclusion

    We reviewed the available data, including the comments received, 
and determined that air safety and the public interest require adopting 
this 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 this AD.

Costs of Compliance

    We estimate that this AD will affect about 377 engines of U.S. 
registry. Of these 377 engines, we estimate 95 engines operate to 
Flight Profile D or E. The average labor rate is $85 per hour. We do 
not estimate any labor cost is associated with this AD because the 
affected parts are replaced at the next shop visit. Prorated cost of 
parts adjusted to Flight Profile D operation, will cost about $77,672 
per engine. Prorated cost of parts, adjusted to Flight Profile E 
operation, will cost about $204,981 per engine. Based on these figures, 
we estimate the cost of this AD on U.S. operators to be $11,834,655.

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),
    (3) Will not affect intrastate aviation in Alaska to the extent 
that it justifies making a regulatory distinction, 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.

[[Page 61173]]

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

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 airworthiness 
directive (AD):

200X-19-17 Rolls-Royce plc Amendment 39-17599; Docket No. FAA-2013-
0029; Directorate Identifier 2013-NE-01-AD.

(a) Effective Date

    This AD becomes effective November 7, 2013.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all Rolls-Royce plc (RR) RB211-535E4-B-37 
series turbofan engines.

(d) Unsafe Condition

    This AD was prompted by recalculating the lives of certain 
rotating life limited parts (LLPs) operated to certain flight 
profiles. We are issuing this AD to prevent the failure of rotating 
LLPs, which could result in uncontained failure of the engine and 
damage to the airplane.

(e) Actions and Compliance

    Comply with this AD within the compliance times specified, 
unless already done.
    (1) Within 30 days after the effective date of this AD, for 
engines that have operated to Flight Profile D or E, recalculate the 
life of the low-pressure (LP) turbine disc stage 2, intermediate-
pressure (IP) compressor rotor shaft (stage 1 to 6), high-pressure 
(HP) compressor rear rotor shaft assembly, and HP turbine disc 
installed on that engine. Use the part lives, prorated life 
formulas, and flight profiles in Appendices 2, 4, and 5 of RR Alert 
Non-Modification Service Bulletin (NMSB) No. RB.211-72-AG875, dated 
December 13, 2012, to make that calculation.
    (2) Within 30 days after the effective date of this AD, for 
engines that will operate to Flight Profile D or E, assign the 
maximum approved lives defined in Appendix 2 of RR Alert NMSB No. 
RB.211-72-AG875, dated December 13, 2012, to the LP turbine disc 
stage 2, IP compressor rotor shaft (stage 1 to 6), HP compressor 
rear rotor shaft assembly, and HP turbine disc based on the flight 
profile that will be flown.
    (3) For engines that have only operated to, and will continue to 
operate to, Flight Profile C, as defined in Appendix 5 of RR Alert 
NMSB No. RB.211-72-AG875, dated December 13, 2012, no further action 
is required by this AD.
    (4) After the effective date of this AD, for engines that 
incorporate an LP turbine disc stage 2, IP compressor rotor shaft 
(stage 1 to 6), HP compressor rear rotor shaft assembly, or HP 
turbine disc whose part life is defined by paragraph (e)(1) of this 
AD, that have an engine shop visit (ESV) before reaching the part 
life assigned in paragraph (e)(2) of this AD, remove each part from 
service before the part exceeds the part life assigned in paragraph 
(e)(2).
    (5) For those engines that incorporate an LP turbine disc stage 
2, IP compressor rotor shaft (stage 1 to 6), HP compressor rear 
rotor shaft assembly, or HP turbine disc whose part life is defined 
by paragraph (e)(1) of this AD, that do not have an ESV after the 
effective date of this AD before the part exceeds the part life 
assigned in paragraph (e)(2) of this AD, remove the part from 
service at the next ESV.

(f) Installation Prohibition

    Any LP turbine disc stage 2, IP compressor rotor shaft (stage 1 
to 6), HP compressor rear rotor shaft assembly, or HP turbine disc 
whose part life is defined by paragraph (e)(1) of this AD that is 
re-installed in any engine after the effective date of this AD must 
be removed from service before the part exceeds the part life 
assigned in paragraph (e)(2) of this AD.

(g) Definition

    For the purpose of this AD, ESV is whenever engine maintenance 
performed prior to reinstallation requires the separation of a pair 
of major mating engine module flanges. Separation of flanges solely 
for the purpose of shipment without subsequent internal maintenance 
is not an ESV. Separation of the external gearbox engine mating 
flanges or removal of the external gearbox is also not classified as 
a shop visit.

(h) Alternative Methods of Compliance (AMOCs)

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

(i) Related Information

    (1) For more information about this AD, contact Robert Green, 
Aerospace Engineer, Engine Certification Office, FAA, Engine & 
Propeller Directorate, 12 New England Executive Park, Burlington, MA 
01803; phone: 781-238-7754; fax: 781-238-7199; email: 
[email protected].
    (2) Refer to European Aviation Safety Agency AD 2012-0265, dated 
December 18, 2012, for related information. You may examine the AD 
on the Internet at http://www.regulations.gov/#!documentDetail;D=FAA-2013-0029-0007.

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Rolls-Royce plc Alert Non-Modification Service Bulletin No. 
RB.211-72-AG875, dated December 13, 2012.
    (ii) Reserved.
    (3) For Rolls-Royce plc 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-
1332-249936; email: http://www.rolls-royce.com/contact/civil_team.jsp; or download from https://www.aeromanager.com.
    (4) You may view this service information at FAA, Engine & 
Propeller Directorate, 12 New England Executive Park, Burlington, 
MA. For information on the availability of this material at the FAA, 
call 781-238-7125.
    (5) You may view this service information 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 September 16, 2013.
Carlos A. Pestana,
Acting Directorate Assistant Manager, Engine & Propeller Directorate, 
Aircraft Certification Service.
[FR Doc. 2013-23452 Filed 10-2-13; 8:45 am]
BILLING CODE 4910-13-P

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