Airworthiness Directives; Rolls-Royce plc (RR) Models Trent 768-60, 772-60, 772B-60, and 772C-60 Turbofan Engines

[Federal Register Volume 73, Number 105 (Friday, May 30, 2008)]
[Rules and Regulations]
[Pages 31019-31021]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-12061]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0597; Directorate Identifier 2008-NE-12-AD; 
Amendment 39-15542; AD 2008-11-19]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce plc (RR) Models Trent 768-
60, 772-60, 772B-60, and 772C-60 Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule; request for comments.

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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:

    Three Trent 700 IP Turbine discs that exhibited signs of wear at 
the bore following failure of the bearing chamber sealing sleeve 
were returned to service. This was based on the fact that Non-
Destructive Testing (NDT) did not reveal micro cracking on the 
affected disc areas. Further engineering investigation considered 
that, although no micro cracking had been found, the worn disc bore 
surfaces would have an associated fatigue penalty compared to an 
unaffected bore. A crack developing from these rubbed surfaces could 
potentially lead to a disc burst.
    As the described wear, present at the bores of those three 
discs, presents a potential unsafe condition, this Airworthiness 
Directive requires identification of the three affected serial 
numbers of IP Turbine Discs (P/N FK20795) and removal from service 
prior to attaining a certain number of cycles, as indicated.

We are issuing this AD to prevent a failure of the intermediate 
pressure (IP) turbine disc that could result in an uncontained failure 
of the engine and possible damage to the airplane.

DATES: This AD becomes effective June 16, 2008.
    We must receive comments on this AD by June 30, 2008.

ADDRESSES: You may send comments by any of the following methods:
    <bullet> Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
    <bullet> Mail: U.S. Department of Transportation, 1200 New Jersey 
Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 
20590-0001.
    <bullet> Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    <bullet> Fax: (202) 493-2251.

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 (telephone (800) 647-5527) is the same as 
the Mail address provided in the ADDRESSES section. Comments will be 
available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: James Lawrence, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (781) 238-7176; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Discussion

    The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community, has issued EASA 
Airworthiness Directive 2007-0267-E, dated October 8, 2007 (referred to 
after this as ``the MCAI''), to correct an unsafe condition for the 
specified products. The MCAI states:

    Three Trent 700 IP Turbine discs that exhibited signs of wear at 
the bore following failure of the bearing chamber sealing sleeve 
were returned to service. This was based on the fact that Non-
Destructive Testing (NDT) did not reveal micro cracking on the 
affected disc areas. Further engineering investigation considered 
that, although no micro cracking had been found, the worn disc bore 
surfaces would have an associated fatigue penalty compared to an 
unaffected bore. A crack developing from these rubbed surfaces could 
potentially lead to a disc burst.
    As the described wear, present at the bores of those three 
discs, presents a potential unsafe condition, this Airworthiness 
Directive requires identification of the three affected serial 
numbers of IP Turbine Discs (P/N FK20795) and removal from service 
prior to attaining a certain number of cycles, as indicated.

    You may obtain further information by examining the MCAI in the AD 
docket.

[[Page 31020]]

Relevant Service Information

    Rolls-Royce has issued Alert Service Bulletin RB.211-72-AF734, 
dated October 3, 2007. The actions described in this service 
information are intended to correct the unsafe condition identified in 
the MCAI.

FAA's Determination and Requirements of This AD

    This product has been approved by the aviation authority of the 
United Kingdom, and is approved for operation in the United States. 
Pursuant to our bilateral agreement with the United Kingdom, they have 
notified us of the unsafe condition described in the EASA AD and 
service information referenced above. We are proposing this AD because 
we evaluated all information provided by EASA and determined the unsafe 
condition exists and is likely to exist or develop on other products of 
the same type design.

FAA's Determination of the Effective Date

    Since there are currently no domestic operators of this engine 
model, notice and opportunity for public comment before issuing this AD 
are unnecessary. A situation exists that allows the immediate adoption 
of this regulation.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety, and we did not precede it by notice and opportunity for public 
comment. We invite you to send any written relevant data, views, or 
arguments about this AD. Send your comments to an address listed under 
the ADDRESSES section. Include ``Docket No. FAA-2008-0597; Directorate 
Identifier 2008-NE-12-AD'' at the beginning of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this AD. We will consider all 
comments received by the closing date and may amend this AD because of 
those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this AD. Using the search function of the Web site, 
anyone can find and read the comments in any of our dockets, including, 
if provided, the name of the individual who sent the comment (or signed 
the comment on behalf of an association, business, labor union, etc.). 
You may review the DOT's complete Privacy Act Statement in the Federal 
Register published on April 11, 2000 (65 FR 19477-78).

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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
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:

2008-11-19 Rolls-Royce plc: Amendment 39-15542; Docket No. FAA-2008-
0597; Directorate Identifier 2008-NE-12-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective June 16, 
2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Rolls-Royce plc models Trent 768-60, 772-
60, 772B-60, 772C-60 turbofan engines with intermediate pressure 
(IP) turbine discs, part number (P/N) FK20795, that have a serial 
number specified in Table 1 of this AD, installed. These engines are 
installed on, but not limited to, Airbus 330 series airplanes.

Reason

    (d) Three Trent 700 IP Turbine discs that exhibited signs of 
wear at the bore following failure of the bearing chamber sealing 
sleeve were returned to service. This was based on the fact that 
Non-Destructive testing (NDT) did not reveal micro cracking on the 
affected disc areas. Further engineering investigation considered 
that, although no micro cracking had been found, the worn disc bore 
surfaces would have an associated fatigue penalty compared to an 
unaffected bore. A crack developing from these rubbed surfaces could 
potentially lead to a disc burst.
    As the described wear, present at the bores of those three 
discs, presents a potentially unsafe condition, this Airworthiness 
Directive requires identification of the three affected serial 
numbers of IP Turbine Discs (P/N FK20795) and removal from service 
prior to attaining a certain number of cycles, as indicated.
    We are issuing this AD to prevent a failure of the IP turbine 
disc that could result in an uncontained failure of the engine and 
possible damage to the airplane.

Actions and Compliance

    (e) Unless already done, do the following actions.
    (1) The affected IP Turbine Discs, P/N FK20795, must be removed 
from service prior to attaining the following number of Cycles Since 
New (CSN):

   Table 1.--IP Turbine Discs by Engine Serial Number and Disc Serial
                                 Number
------------------------------------------------------------------------
                                                           Removal limit
                       Serial No.                             in CSN
------------------------------------------------------------------------
CREB452.................................................           7,960
CREB216.................................................           7,930
CREB322.................................................           7,500
------------------------------------------------------------------------

    (2) For detailed instructions, refer to Rolls-Royce RB211 
Propulsion System Non-Modification Service Bulletin RB211-72-

[[Page 31021]]

AF734 original issue, section 3. Accomplishment Instructions.

FAA AD Differences

    (f) None.

Other FAA AD Provisions

    (g) Alternative Methods of Compliance (AMOCs): 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 MCAI EASA Airworthiness Directive 2007-0267-E, 
dated October 8, 2007, and RR Alert Service Bulletin RB.211-72-
AF734, dated October 3, 2007, for related information.
    (i) Contact James Lawrence, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone (781) 238-7176; fax (781) 238-
7199, for more information about this AD.

Material Incorporated by Reference

    (j) None.

    Issued in Burlington, Massachusetts, on May 23, 2008.
Robert G. Mann,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E8-12061 Filed 5-29-08; 8:45 am]
BILLING CODE 4910-13-P

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