Airworthiness Directives; Rolls-Royce plc Turbofan Engines

[Federal Register Volume 78, Number 192 (Thursday, October 3, 2013)]
[Rules and Regulations]
[Pages 61168-61171]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-23448]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0052; Directorate Identifier 2013-NE-02-AD; 
Amendment 39-17600; AD 2013-19-18]
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) RB211-535E4-37, RB211-535E4-B-37, RB211-535E4-C-
37, and RB211-535E4-B-75 turbofan engines. This AD requires removal of 
affected parts using a drawdown plan. This AD was prompted by RR 
updating the low-cycle-fatigue life analysis for the low pressure 
turbine (LPT) stage 2 discs. We are issuing this AD to prevent LPT 
stage 2 disc failure, which could result in uncontained engine damage 
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), 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.

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 
20507). The NPRM proposed to correct an unsafe condition for the 
specified products. The MCAI states:

    A recent re-evaluation of Critical Part lives carried out by 
Rolls-Royce revealed changes to the thermal profile and stresses in 
certain features of the low pressure turbine (LPT) Stage 2 disc. 
These changes have resulted in a reduction of the cyclic life of the 
LPT stage 2 discs.
    Operation of an engine equipped with a Critical Part that has 
exceeded its cyclic life may result in Critical Part failure, 
consequent 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 20507, 
dated April 5, 2013).

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

    Texas Aero Engine Services LLC 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-AH029, dated 
December 13, 2012, 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-AH029, 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 ESV definition is not consistent with the instructions in RR 
Alert NMSB No. RB.211-72-AH029, dated December 13, 2012, which only 
applies when the LPT Module will be stripped and the affected rotor is 
debladed. Our ESV

[[Page 61169]]

definition will result in removal of parts earlier than would occur 
using the RR NMSB. RR noted that this is unnecessary 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. 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, an 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 Airlines (AAL), FedEx Express, 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 
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. LPT stage 2 discs 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)(4) of 
this AD regarding removal of affected parts by the compliance date, and 
that the parts cannot exceed current life limits. AAL 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)(4) of this AD could 
be misinterpreted because we did not specify that paragraph (e)(3) 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 TLM 
limits for the RR RB211 engine cannot be exceeded.
    We changed paragraph (e)(3) of this AD by inserting ``before 
reaching the part life assigned in paragraph (e)(2)''. The paragraph 
now reads: ``(3) After the effective date of this AD, for engines that 
have an engine shop visit (ESV) before reaching the part life assigned 
in paragraph (e)(2) of this AD, remove the LPT stage 2 disc from 
service before the part exceeds the part life assigned in paragraph 
(e)(2).''

Request To Change Compliance To Be Consistent With the RR Alert NMSB

    AAL, RR, and UAL requested that we change the compliance to be 
consistent with RR Alert NMSB No. RB.211-72-AH029, dated December 13, 
2012. This AD requires that the reduced life limits be assigned within 
30 days after the effective date of the AD. The RR Alert NMSB 
establishes that these lives are provisional lives, and that the 
current lives as published in the TLM remain in effect until November 
30, 2016. AAL and RR 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 noted that the AD as proposed (78 FR 20507, 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-AH029, dated December 13, 2012, was 6 weeks. The new 
lives of the LPT stage 2 discs 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 at an ESV (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, which 
will result 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 life-limited 
parts. We do not consider the engine disassembly costs that will vary 
depending on the category of the ESV. We did not change this AD.

Comment That the European Aviation Safety Agency (EASA) AD Referred to 
in the NPRM Has Been Superseded

    RR commented that EASA AD 2012-0266, dated December 18, 2012, 
referred to in this AD, has been superseded.
    We disagree. EASA AD 2012-0266 is not superseded. 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 would affect about 220 engines installed 
on airplanes of U.S. registry. The average labor rate is $85 per hour. 
We do not estimate any

[[Page 61170]]

labor cost associated with this AD because the affected parts are 
replaced during scheduled shop visits. Prorated cost of the parts 
adjusted for lost life is about $8,290 per engine. Based on these 
figures, we estimate the cost of the AD on U.S. operators to be 
$1,823,800.

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.
    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):

2013-19-18 Rolls-Royce plc: Amendment 39-17600; Docket No. FAA-2013-
0052; Directorate Identifier 2013-NE-02-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) RB211-535E4-37, 
RB211-535E4-B-37, RB211-535E4-C-37, and RB211-535E4-B-75 turbofan 
engines.

(d) Unsafe Condition

    This AD was prompted by RR updating the low-cycle-fatigue life 
analysis for the low pressure turbine (LPT) stage 2 discs. We are 
issuing this AD to prevent LPT stage 2 disc failure, which could 
result in uncontained engine damage and damage to the airplane.

(e) Actions and Compliance

    (1) Within 30 days after the effective date of this AD, re-
calculate the cyclic life since new of each LPT stage 2 disc. Use 
the part lives and prorated life formulas in Appendices 1, 2, and 3 
of RR Alert Non-Modification Service Bulletin (NMSB) No. RB.211-72-
AH029, dated December 13, 2012, to make that calculation.
    (2) Assign the Maximum Approved Lives defined in Appendix 1 of 
Alert NMSB No. RB.211-72-AH029, dated December 13, 2012, to the LPT 
stage 2 disc based on the flight profile that will be flown.
    (3) After the effective date of this AD, for engines that have 
an engine shop visit (ESV), before reaching the part life assigned 
in paragraph (e)(2) of this AD, remove the LPT stage 2 disc from 
service before the part exceeds the part life assigned in paragraph 
(e)(2).
    (4) For those engines 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

    Except for parts that have been reworked using RR Service 
Bulletin No. RB.211-72-D365, Revision 5, dated December 13, 2012, 
after the effective date of this AD, do not reinstall any part 
removed per this AD into any engine.

(g) Definition

    For the purpose of this AD, an 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, FAA, may approve AMOCs 
to 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 Airworthiness 
Directive 2012-0266, dated December 18, 2012 for more information. 
You may examine the AD on the Internet at http://www.regulations.gov/#!documentDetail;D=FAA-2013-0052-0004.

(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) RR Alert Non-Modification Service Bulletin (NMSB) No. 
RB.211-72-AH029, 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.


[[Page 61171]]


    Issued in Burlington, Massachusetts, on September 16, 2013.
Carlos A. Pestana,
Acting Directorate Assistant Manager, Engine & Propeller Directorate, 
Aircraft Certification Service.
[FR Doc. 2013-23448 Filed 10-2-13; 8:45 am]
BILLING CODE 4910-13-P

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