Airworthiness Directives; Rolls-Royce plc Turbofan Engines

[Federal Register Volume 77, Number 45 (Wednesday, March 7, 2012)]
[Rules and Regulations]
[Pages 13485-13488]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-5371]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0959; Directorate Identifier 2011-NE-25-AD; 
Amendment 39-16970; AD 2012-04-14]
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 RB211-
Trent 800 series turbofan engines. This AD requires inspecting the 
front combustion liner head section for cracking, and if found cracked, 
removing the front combustion liner head section from service at the 
next shop visit. This AD was prompted by mandatory continuing 
airworthiness information (MCAI) issued by an aviation authority of 
another country to identify and correct an unsafe condition on an 
aviation product. Specifically, routine inspections revealed cracking 
on the head sections of two RB211-Trent 800 front combustion liners. We 
are issuing this AD to prevent uncontained engine failure and damage to 
the airplane.

DATES: This AD becomes effective April 11, 2012. The Director of the 
Federal Register approved the incorporation by reference of certain 
publications listed in this AD as of April 11, 2012.

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; email: 
[email protected]; phone: 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 November 25, 2011 
(76 FR 72650). That NPRM proposed to correct an unsafe condition for 
the specified products. The MCAI states:

    Routine inspections have revealed cracking on the head sections 
of two Trent 800 front combustion liners.
    This condition, if not detected and corrected, could lead to hot 
gas breakout with subsequent downstream component release 
potentially leading to uncontained high energy debris, possibly 
resulting in damage to the aeroplane or injury to persons on the 
ground.

Comments

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

Request To Reference the Latest Service Information

    American Airlines, The Boeing Company, and Rolls-Royce plc, 
requested that we reference the latest service information, which is 
Alert Service Bulletin (ASB) No. RB.211-72-AG456, Revision 1, dated 
November 4, 2011.
    We agree. We changed the AD to reference Revision 1 of the ASB.

Request To Add Previous Credit Paragraph

    American Airlines, The Boeing Company, and Rolls-Royce plc, 
requested that we add a Previous Credit paragraph to list the original 
ASB to give credit to operators who have performed the initial and 
repetitive inspections before the effective date of the AD.
    We agree. We added Credit for Previous Action paragraph (i) to the 
AD.

Request To Borescope-Inspect the 04 Module When Removed

    Rolls-Royce plc requested that we add wording to the AD that states 
that the 04 module may be borescope-inspected when it is removed from 
the engine but is not being stripped. This would give the operator the 
opportunity to restart the 2,000-cycle on-wing life before the next 
inspection, or if cracked, would give the operator the opportunity to 
replace the front combustion liner head section.
    We agree. We changed the AD to allow as an alternate procedure, an 
in-shop borescope inspection.

Request To Eliminate Unnecessary Borescope Inspection

    Rolls-Royce plc pointed out that the proposed AD requires the front 
combustion liner head section to be borescope inspected even if it is 
being stripped. Visual and fluorescent penetrant inspections would be 
done as part of the maintenance manual activities after stripping, and 
the borescope inspection would be unnecessary.

[[Page 13486]]

    We agree. We changed the AD to eliminate the unnecessary borescope 
inspection.

Request To Clarify AD Meaning

    American Airlines and The Boeing Company requested that we change 
paragraphs (f)(2) and (g)(1)(i) to state that if you find cracking, 
repetitively inspect the front combustion liner as specified in Table 1 
and remove it from service as specified in Table 1 or at the next shop 
visit, whichever occurs first. The commenters claim that this change 
would clarify the meaning of the AD.
    We do not agree. Any engine found to have cracks during the initial 
inspection in paragraph (f)(1) or a repetitive inspection in paragraph 
(g)(1) must have its front combustor liner head section removed from 
service at the next shop visit. Table 1 allows for further flight with 
mitigating actions until the next shop visit. We did not change the AD.

Request To Identify the Repetitive Inspections Paragraph

    The Boeing Company requested that we identify the repetitive 
inspections paragraph, as paragraph (g).
    We do not agree. The paragraph is already identified as paragraph 
(g). We did not change the AD.

Request To Remove Erroneous Reference

    American Airlines requested that in paragraph (g)(2), we not 
reference paragraph (f)(2) as being a step that would find cracks, 
because it does not.
    We agree. We removed that reference in the AD.

Request To Revise Shop Visit Definition and To Inspect During All Shop 
Visits

    American Airlines requested that we revise the definition of shop 
visit to include all engine shop visits, and revise paragraph (g)(2) of 
the proposed AD such that paragraph 3.B.(1) or 3.B.(2) of the ASB can 
be used to do the inspections. The commenter stated that the proposed 
AD shop visit definition limits the number of shop visits where an 
inspection is required. Further, paragraph (g)(2) of the proposed AD is 
inconsistent with the definition of shop visit in the ASB because the 
ASB has instructions for borescope inspection when the front combustor 
liner head section is not exposed.
    We partially agree. We agree with revising paragraph (g)(2) (now 
paragraph (g)(3) in the AD) and paragraph (h), because Revision 1 of 
the ASB is worded differently from the original ASB, and Revision 1 of 
the ASB added an alternate borescope inspection that can be performed 
without disassembling the 04 module.
    We do not agree with requiring the inspection during all shop 
visits because the mitigating actions in Table 1 of the AD are 
sufficient to ensure safe operation pending a shop visit in accordance 
with the definition of shop visit in the AD. We changed paragraph 
(g)(2) (now paragraph (g)(3)) from:
    ``For engines not found to have cracks in the front combustion 
liner head section in accordance with paragraphs (f)(1), (f)(2), or 
(g)(1) of this AD, at every shop visit after the effective date of this 
AD, inspect the front combustion liner head section for cracking. Use 
paragraph B.(2), except B.(2)(a)(i), of the In-shop Accomplishment 
Instructions of RR ASB No. RB.211-72-AG456, dated September 9, 2010, to 
do the inspections,'' to:
    ``For engines not found to have cracks in the front combustion 
liner head section in accordance with paragraphs (f)(1) or (g)(1) of 
this AD, at every shop visit after the effective date of this AD:
    (i) Fluorescent-penetrant inspect the front combustion liner head 
section for cracking; or
    (ii) Borescope-inspect the front combustion liner head section for 
cracking. Use paragraph 3.B.(1)(b) except paragraph 3.B.(1)(b)(i), or 
use paragraphs 3.B.(2)(b) through 3.B.(2)(d), of the In-shop 
Accomplishment Instructions of RR ASB No. RB.211-72-AG456, Revision 1, 
dated November 4, 2011.
    (iii) If any cracks are found, reject the front combustion liner.''
    We also changed paragraph (h) from:
    ``For the purpose of this AD, the term shop visit means the 
induction of an engine into the shop for maintenance where the front 
combustion liner is exposed or when the engine has been removed from 
service as a result of paragraph (f)(2) or (g)(1)(i) of this AD,'' to:
    ``For the purpose of this AD, the term shop visit means the 
induction of an engine into the shop for maintenance where the front 
combustion liner is exposed, or when the 04 module has been removed 
from the engine or when the engine has been removed from service as a 
result of paragraph (f)(2) or (g)(2) of this AD.''

Request To Change Action Wording in Table 1

    The Boeing Company requested that we change the action wording in 
Table 1 of the proposed AD from ``Replace the engine before next 
flight'' to ``Remove the engine immediately.'' The commenter stated 
that this would make the AD consistent with the ASB and prevent 
failures on the ground.
    We do not agree. Engine running on the ground is not a flight 
safety issue. We note, however, that the NPRM (76 FR 72650, November 
25, 2011) used both ``remove the engine'' and ``replace the engine'' in 
Table 1. We changed Table 1 in the AD to use the phrase, ``remove the 
engine'' in each case.

Need To Show All Acceptable Means of Completing the On-Wing Inspection

    Since we issued the NPRM (76 FR 72650, November 25, 2011), we 
determined that to be consistent with Revision 1 of the ASB, we need to 
show all acceptable means of completing the on-wing inspection. We 
changed paragraphs (f)(1) and (g)(1) of the proposed AD from:
    ``Within 1,000 flight cycles (FCs) after the effective date of this 
AD, inspect the front combustion liner head section for cracking. Use 
paragraph 3.A, except for 3.A.(1)(a)(i), of the On-Wing Accomplishment 
Instructions of RR ASB No. RB.211-72-AG456, dated September 9, 2010, to 
do your inspections'' to:
    ``Within 1,000 flight cycles (FCs) after the effective date of this 
AD, inspect the front combustion liner head section for cracking. Use 
paragraph 3.A.(1), except for 3.A.(1)(a)(i), or paragraphs 3.A.(2)(b) 
through 3.A.(2)(d) of the On-Wing Accomplishment Instructions of RR ASB 
No. RB.211-72-AG456, Revision 1, dated November 4, 2011, to do your 
inspections.''

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

    We estimate that this AD will affect about 125 products of U.S. 
registry. We also estimate that it will take about 10 work-hours per 
engine to inspect and 10 additional work-hours for those combustion 
liners that require replacement. The average labor rate is $85 per 
work-hour. Required parts will cost about $525,000 per engine. We 
expect that four front combustion liners will require replacement. 
Based on these figures, we estimate the cost of the AD on U.S. 
operators to be $2,209,650.

[[Page 13487]]

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 airworthiness 
directive (AD):

2012-04-14 Rolls-Royce plc: Amendment 39-16970; Docket No. FAA-2011-
0959; Directorate Identifier 2011-NE-25-AD.

(a) Effective Date

    This AD becomes effective April 11, 2012.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Rolls-Royce plc (RR) RB211-Trent 800 turbofan 
engines, all models, all serial numbers.

(d) Reason

    (1) 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:
    Routine inspections have revealed cracking on the head sections 
of two Trent 800 front combustion liners.
    This condition, if not detected and corrected, could lead to hot 
gas breakout with subsequent downstream component release 
potentially leading to uncontained high energy debris, possibly 
resulting in damage to the aeroplane or injury to persons on the 
ground.
    (2) We are issuing this AD to prevent uncontained engine failure 
and damage to the airplane.

(e) Actions and Compliance

    Unless already done, do the following actions.

(f) Initial Inspection

    (1) Within 1,000 flight cycles (FCs) after the effective date of 
this AD, inspect the front combustion liner head section for 
cracking. Use paragraph 3.A.(1), except for 3.A.(1)(a)(i), or 
paragraphs 3.A.(2)(b) through 3.A.(2)(d) of the On-Wing 
Accomplishment Instructions of RR Alert Service Bulletin (ASB) No. 
RB.211-72-AG456, Revision 1, dated November 4, 2011, to do your 
inspections.
    (2) If you find cracking, remove the front combustion liner head 
section from service at the next shop visit. Until the next shop 
visit, take the corrective actions listed in Table 1 of this AD, as 
applicable.

                               Table 1--Inspection Findings and Follow-on Actions
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            Inspection findings                                Action(s) and compliance time(s)
----------------------------------------------------------------------------------------------------------------
(i) Cumulative crack length up to 150 mm     Reduce the inspection intervals to 250 FCs.
 (up to 2 heatshields).
(ii) Cumulative crack length 150 mm to 300   Reduce the inspection intervals to 100 FCs.
 mm (up to 4 heatshields).
(iii) Cumulative crack length 300 mm to 450  Remove the engine within 50 FCs.
 mm (up to 6 heatshields).
(iv) Cumulative crack length 450 mm to 900   Remove the engine within 5 FCs.
 mm (up to 12 heatshields).
(v) Cumulative crack length greater than     Remove the engine before next flight.
 900 mm (more than 12 heatshields).
----------------------------------------------------------------------------------------------------------------

(g) Repetitive Inspections

    (1) Within 1,000 FCs after the effective date of this AD, 
inspect the front combustion liner head section for cracking. Use 
paragraph 3.A.(1), except for 3.A.(1)(a)(i), or paragraphs 
3.A.(2)(b) through 3.A.(2)(d) of the On-Wing Accomplishment 
Instructions of RR ASB No. RB.211-72-AG456, Revision 1, dated 
November 4, 2011, to do your inspections.
    (2) If you find cracking, remove the front combustion liner head 
section at the next shop visit. Until the next shop visit, take the 
corrective actions as detailed in Table 1 of this AD, as applicable.
    (3) For engines not found to have cracks in the front combustion 
liner head section in accordance with paragraphs (f)(1) or (g)(1) of 
this AD, at every shop visit after the effective date of this AD:
    (i) Fluorescent-penetrant inspect the front combustion liner 
head section for cracking; or
    (ii) Borescope-inspect the front combustion liner head section 
for cracking. Use paragraph 3.B.(1)(b) except paragraph 
3.B.(1)(b)(i), or use paragraphs 3.B.(2)(b) through 3.B.(2)(d), of 
the In-shop Accomplishment Instructions of RR ASB No. RB.211-72-
AG456, Revision 1, dated November 4, 2011.
    (iii) If any cracks are found, reject the front combustion 
liner.
    (4) Accomplishment of a shop visit inspection as required by 
paragraph (g)(3) of this AD may substitute for the accomplishment of 
an on-wing inspection as

[[Page 13488]]

required by paragraph (f)(1) or (g)(1) of this AD.

(h) Definition of Shop Visit

    For the purpose of this AD, the term shop visit means the 
induction of an engine into the shop for maintenance where the front 
combustion liner is exposed, or when the 04 module has been removed 
from the engine, or when the engine has been removed from service as 
a result of paragraph (f)(2) or (g)(2) of this AD.

(i) Credit for Previous Action

    An initial or repetitive inspection performed before the 
effective date of this AD using RR ASB No. RB.211-72-AG456, dated 
September 9, 2010, satisfies the initial inspection requirement in 
paragraph (f) or repetitive inspection requirement in paragraph (g) 
of this AD.

(j) 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.

(k) Related Information

    (1) For more information about this AD, contact Alan Strom, 
Aerospace Engineer, Engine Certification Office, FAA, Engine & 
Propeller Directorate, 12 New England Executive Park, Burlington, MA 
01803; email: [email protected]; phone: 781-238-7143; fax: 781-238-
7199.
    (2) Refer to European Aviation Safety Agency AD 2011-0080, dated 
May 6, 2011, for related information.

(l) Material Incorporated by Reference

    (1) You must use the following service information to do the 
actions required by this AD, unless the AD specifies otherwise. The 
Director of the Federal Register approved the incorporation by 
reference (IBR) under 5 U.S.C. 552(a) and 1 CFR part 51.
    (i) Rolls-Royce plc Alert Service Bulletin No. RB.211-72-AG456, 
Revision 1, dated November 4, 2011.
    (ii) Rolls-Royce plc Alert Service Bulletin No. RB.211-72-AG456, 
dated September 9, 2010.
    (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; email: http://www.rolls-royce.com/contact/civil_team.jsp; or Web: https://www.aeromanager.com.
    (3) You may review copies of the service information at the 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.
    (4) You may also review copies of the service information 
incorporated by reference 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 February 22, 2012.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-5371 Filed 3-6-12; 8:45 am]
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