Document ID: FAA-2007-0078-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Rolls-Royce plc RB211 Series Turbofan Engines
Posted Date: 2008-02-21T05:00Z

[Federal Register: February 21, 2008 (Volume 73, Number 35)]
[Proposed Rules]               
[Page 9502-9504]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21fe08-26]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0078; Directorate Identifier 2007-NE-40-AD]
RIN 2120-AA64

 
Airworthiness Directives; Rolls-Royce plc RB211 Series Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed AD results from mandatory 
continuing airworthiness information (MCAI) originated 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:

    High pressure (HP) turbine discs recently inspected in 
accordance with the Engine Manual have exhibited cracks in the disc 
rim. The discs have failed to meet the inspection acceptance 
criteria and have been returned to Rolls-Royce for engineering 
investigation. This investigation has concluded that the cracks have 
resulted from scores within the cooling air holes in the disc rim 
that could have been introduced during new part

[[Page 9503]]

manufacture or during overhaul of the disc. The engineering 
investigation has concluded that if this cracking was undetected 
then it could result in uncontained disc failure and a potential 
unsafe condition for the aircraft.

We are proposing this AD to prevent uncontained disc failure, possibly 
resulting in damage to the airplane.

DATES: We must receive comments on this proposed AD by March 24, 2008.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov
 and follow the instructions for sending your 

comments electronically.
     Mail: Docket Management Facility: U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     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 proposed 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: Ian Dargin, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
ian.dargin@faa.gov; telephone (781) 238-7178, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2007-0078; Directorate 
Identifier 2007-NE-40-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this proposed AD. We will consider 
all comments received by the closing date and may amend this proposed 
AD based on 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 proposed AD.

Discussion

    The European Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Community, has issued AD 
2006-0180, dated June 26, 2006, for RB211-524 series engines, AD 2006-
0181, dated June 26, 2006, for RB211-22B engines, and AD 2006-0182, 
dated June 28, 2006, for RB211-535 series engines, to correct the same 
unsafe condition for the specified products. The EASA ADs state:

    HPT discs recently inspected in accordance with the Engine 
Manual have exhibited cracks in the disc rim. The discs have failed 
to meet the inspection acceptance criteria and have been returned to 
Rolls-Royce for engineering investigation. This investigation has 
concluded that the cracks have resulted from scores within the 
cooling air holes in the disc rim that could have been introduced 
during new part manufacture or during overhaul of the disc. The 
engineering investigation has concluded that if this cracking was 
undetected then it could result in uncontained disc failure and a 
potential unsafe condition for the aircraft.

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

Relevant Service Information

    Rolls-Royce plc has issued Alert Service Bulletin No. RB.211-72-
AE969, dated May 9, 2006. The actions described in this service 
information are intended to correct the unsafe condition identified in 
the MCAI ADs.

FAA's Determination and Requirements of This Proposed AD

    These products have been approved by the United Kingdom (UK), and 
are approved for operation in the United States. Pursuant to our 
bilateral agreement with the UK, they have notified us of the unsafe 
condition described in the MCAI ADs, and service information referenced 
above. We are proposing this AD because we evaluated all pertinent 
information and determined an unsafe condition exists and is likely to 
exist or develop on other products of the same type design. This 
proposed AD would require initial and repetitive eddy current 
inspections of HP turbine discs.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD 
would affect about 506 products of U.S. registry. We also estimate that 
it would take about 4 work-hours per product to comply with the basic 
requirements of this proposed AD. The average labor rate is $80 per 
work-hour. Based on these figures, we estimate the cost of the proposed 
AD on U.S. operators to be $161,920.

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 proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would 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 proposed 
regulation:
    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 proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator,

[[Page 9504]]

the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    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]

    2. The FAA amends Sec.  39.13 by adding the following new 
airworthiness directive (AD):

Rolls-Royce plc: Docket No. FAA-2007-0078; Directorate Identifier 
2007-NE-40-AD.

Comments Due Date

    (a) We must receive comments by March 24, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Rolls-Royce plc (RR) models RB211-535E4 
series, RB211-535E4-B series, RB211-535E4-C series, RB211-535C 
series, RB211-524 series, and RB211-22B series turbofan engines. 
These engines are installed on, but not limited to, Boeing 747, 757, 
and 767, Lockheed L-1011, and Tupulev Tu204 airplanes.

Reason

    (d) European Aviation Safety Agency AD 2006-0180, dated June 26, 
2006, AD 2006-0181, dated June 26, 2006, and AD 2006-0182, dated 
June 28, 2006, state:

    High pressure (HP) turbine discs recently inspected in 
accordance with the Engine Manual have exhibited cracks in the disc 
rim. The discs have failed to meet the inspection acceptance 
criteria and have been returned to Rolls-Royce for engineering 
investigation. This investigation has concluded that the cracks have 
resulted from scores within the cooling air holes in the disc rim 
that could have been introduced during new part manufacture or 
during overhaul of the disc. The engineering investigation has 
concluded that if this cracking was undetected then it could result 
in uncontained disc failure and a potential unsafe condition for the 
aircraft.

We are issuing this AD to prevent uncontained disc failure, possibly 
resulting in damage to the airplane.

Actions and Compliance

    (e) Unless already done, perform an initial eddy current 
inspection (ECI) of the HP turbine disc air cooling holes. 
Information on ECI of HP turbine disc cooling holes can be found in 
RR Engine Overhaul Process Manual No. TSD594-J, Overhaul Process 
223, dated May 1, 2001.

Initial Inspection for RB211-22B Series Turbofan Engines

    (f) For RB211-22B series turbofan engines:
    (1) If an installed HP turbine disc has more than 9,500 cycles-
since-new (CSN) on the effective date of this AD, then ECI the HP 
turbine disc by whichever is the soonest of the following 
conditions:
    (i) Within 500 cycles from the effective date of this AD; or
    (ii) At the next shop visit where the HP turbine rotor is 
removed from the combustor outer casing.
    (2) If an installed HP turbine disc has 9,500 or fewer CSN on 
the effective date of this AD, then ECI the HP turbine disc by 
whichever is the soonest of the following conditions:
    (i) Before reaching 10,000 CSN; or
    (ii) At the next shop visit where the HP turbine rotor is 
removed from the combustor outer casing and the HP turbine disc has 
more than 2,750 CSN.
    (3) For HP turbine rotors at shop visit and already removed from 
the combustor outer casing on the effective date of this AD, ECI the 
HP turbine disc before reinstalling the HP turbine rotor in the 
combustor outer casing.

Initial Inspection of RB211-524 Series Turbofan Engines

    (g) For RB211-524 series turbofan engines, ECI the HP turbine 
disc at the soonest of the following after the effective date of the 
AD:
    (1) At the next shop visit where the HP turbine blades are 
removed from the HP turbine disc and when the HP turbine disc has 
more than 2,750 CSN.
    (2) For HP turbine rotors at shop visit and the HP turbine 
blades are removed from the HP turbine disc and the HP turbine disc 
life is more than 2,750 CSN, ECI the turbine disc before 
reinstalling the HP turbine blades.

Initial Inspection of RB211-535C, -535E4, -535E4-B, and -535E4-C Series 
Turbofan Engines

    (h) For RB211-535C, -535E4, -535E4-B, and -535E4-C series 
turbofan engines:
    (1) If an installed HP turbine disc has 17,500 or fewer CSN on 
the effective date of this AD, then ECI the HP turbine disc by 
whichever is the soonest of the following conditions:
    (i) Before reaching 18,000 CSN; or
    (ii) At the next shop visit where the HP turbine rotor is 
removed from the combustor outer casing, and the HP turbine disc has 
5,000 or more CSN.
    (iii) For HP turbine rotors at shop visit on the effective date 
of this AD that are removed from the combustor outer casing, and 
that have HP turbine discs with 5,000 or more CSN, ECI the HP 
turbine disc before reinstalling the HP turbine rotor in the 
combustor outer casing.
    (2) If an installed HP turbine disc has more than 17,500 CSN on 
the effective date of this AD, then ECI the HP turbine disc by 
whichever is the soonest of the following conditions:
    (i) Within 500 cycles from the effective date of this AD; or
    (ii) At the next shop visit where the HP turbine rotor is 
removed from the combustor outer casing.
    (iii) For HP turbine rotors at shop visit on the effective date 
of this AD that are removed from the combustor outer casing, ECI the 
HP turbine disc before reinstalling the HP turbine rotor in the 
combustor outer casing.

HP Turbine Disc Permanent Etching

    (i) On successful completion of the initial inspection only, 
permanently etch NMSB 72-AE969 onto the HP turbine disc, adjacent to 
the part number.

Repetitive ECI Inspections

    (j) Thereafter, perform repetitive ECIs at every shop visit 
where the HP turbine blades are removed from the HP turbine disc. 
Information on ECI of HP turbine disc air cooling holes can be found 
in RR Engine Overhaul Process Manual No. TSD594-J, Overhaul Process 
223, dated May 1, 2001.
    (k) 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.

Previous Credit

    (l) Initial inspections done before the effective date of this 
AD on HP turbine discs with a disc life above the minimum threshold 
(5,000 CSN for the RB211-535 engines and 2,750 CSN for both the 
RB211-524 and the RB211-22B engines) at the time of inspection, per 
paragraph 1.C.(2) of RR Alert Service Bulletin No. RB.211-72-AE969, 
comply with the initial inspection requirements specified in this 
AD.

Related Information

    (m) Refer to EASA AD 2006-0180, dated June 26, 2006, AD 2006-
0181, dated June 26, 2006, and AD 2006-0182, dated June 28, 2006, 
for related information.
    (n) Contact Ian Dargin, Aerospace Engineer, Engine Certification 
Office, FAA, Engine & Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: ian.dargin@faa.gov; 
telephone 781 238-7178; fax 781 238-7199, for more information about 
this AD.

    Issued in Burlington, Massachusetts, on February 13, 2008.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E8-3192 Filed 2-20-08; 8:45 am]

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