

[Federal Register: October 24, 2007 (Volume 72, Number 205)]
[Proposed Rules]               
[Page 60293-60295]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24oc07-26]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-0036; Directorate Identifier 2007-NE-22-AD]
RIN 2120-AA64

 
Airworthiness Directives; Rolls-Royce plc RB211-524 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) provided by the aviation 
authority of the United Kingdom to identify and correct an unsafe 
condition on an aviation product. The MCAI states the following:

    Recently an RB211 HP turbine disc has been found with a crack 
which had propagated further than expected from the risk model that 
was used to establish the original inspection.

    We are proposing this AD to detect cracks that could cause the high 
pressure (HP) turbine disc to fail and result in uncontained failure of 
the engine.

DATES: We must receive comments on this proposed AD by November 23, 
2007.

ADDRESSES: You may send comments by any of the following methods:
     Government-wide rulemaking Web site: Go to http://www.regulations.gov
 and follow the instructions for sending your 

comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., 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.
    You can get the service information identified in this proposed AD 
from Rolls-Royce plc, P.O. Box 31, DERBY, DE24 8BJ, UK, telephone: 44 
(0) 1332 242424; fax: 44 (0) 1332 249936.

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: Jason Yang, Aerospace Engineer, Engine 
Certification Office, FAA, Engine & Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
jason.yang@faa.gov; telephone (781) 238-7747; fax (781) 238-7199.


SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2007-0036; 
Directorate Identifier 2007-NE-22-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory,

[[Page 60294]]

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 
with FAA personnel concerning this proposed 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).

Discussion

    The Civil Aviation Authority (CAA), which is the aviation authority 
for the United Kingdom, has issued United Kingdom Airworthiness 
Directive G-2006-0002, dated February 13, 2006, to correct an unsafe 
condition for the specified products. The CAA AD states:

    A population of HP turbine discs that were manufactured between 
1989-1999 and which were subject to possible machining anomalies, 
were believed to have an increased chance of suffering from cooling 
air hole cracking, compared to the general fleet population of HP 
turbine discs. As a result of this risk, Rolls-Royce issued Non-
Modification Service Bulletin (NMSB) 72-C816, recommending in-
service inspections of the subject discs.
    Recently an RB211 HP turbine disc has been found with a crack 
which had propagated further than expected from the risk model that 
was used to establish the original inspection defined in the above 
NMSB; This has led to the need for a revision of the original 
inspection requirements.
    An HP turbine disc fracture would be uncontained and create a 
potential unsafe condition. Accordingly, this AD introduces revised 
inspection requirements to reflect the increased risk of HP turbine 
disc cracking and potential disc fracture.

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

Relevant Service Information

    RR has issued Service Bulletin RB.211-72-AE718, dated January 24, 
2006. The actions described in this service information are intended to 
correct the unsafe condition identified in the CAA AD.

FAA's Determination and Requirements of This Proposed 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 above. We are issuing 
this AD because we evaluated all the information provided by the CAA 
and determined the unsafe condition exists and is likely to exist or 
develop on other products of the same type design.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD 
would affect about 72 engines installed on airplanes of U.S. registry. 
We also estimate that it would take about 10.0 work-hours per product 
to comply with this proposed AD, and that the average labor rate is $80 
per work-hour. Required parts would cost about $15,000 per product. 
Based on these figures, we estimate the total cost of the proposed AD 
to U.S. operators to be $1,137,600. Our cost estimate is exclusive of 
possible warranty coverage.

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, 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 AD:

Rolls-Royce plc: Docket No. FAA-2007-0036; Directorate Identifier 
2007-NE-22-AD.

Comments Due Date

    (a) We must receive comments by November 23, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Rolls-Royce (RR) RB211-524 series 
turbofan engines with certain high pressure (HP) turbine disks, 
specified by part number (P/N) and serial number (SN) listed in 
Table 1 of this AD, installed. These engines are installed on, but 
not limited to, Boeing 747 series and 767 series airplanes and 
Lockheed L1011 series airplanes.

Reason

    (d) Recently an RB211 HP turbine disc has been found with a 
crack which had propagated further than expected from the risk model 
that was used to establish the original inspection defined in the 
above NMSB; This has led to the need for a revision of the original 
inspection requirements.
    An HP turbine disc fracture would be uncontained and create a 
potential unsafe condition. Accordingly, this AD introduces revised 
inspection requirements to reflect the increased risk of HP turbine 
disc cracking and potential disc fracture.

[[Page 60295]]

Actions and Compliance

    (e) Unless already done, do the following actions.
    (f) Carry out the eddy current inspection as detailed in Section 
3--Accomplishment Instructions of Rolls-Royce NMSB 72-AE718, dated 
January 24, 2006, in accordance with the following schedule:
    (1) The HP disc serial numbers listed in table 1 are to be 
inspected as follows:

                                 Table 1.--HP Disk Serial Numbers by Part Number
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              Part No.                       Serial No.                 Part No.                Serial No.
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UL29473.............................  LAQDY6043                 UL29472................  LQDY9125
UL29473.............................  LAQDY6048                 UL29472................  LQDY9554
UL29473.............................  LAQDY6079                 UL29472................  LQDY9582
UL29473.............................  LDRCZ10057                UL29472................  LQDY9895
UL29473.............................  LDRCZ10264                UL29472................  LQDY9910
UL29473.............................  LDRCZ10415                UL29472................  LQDY9947
UL29473.............................  LDRCZ11402                UL29472................  LQDY9960
UL29473.............................  LDRCZ11425                UL24994................  LQDY6777
UL29473.............................  LDRCZ11497                UL24994................  LQDY6792
UL29473.............................  LDRCZ11663                UL24994................  LQDY6859
UL29473.............................  LDRCZ11679                UL24994................  LQDY6860
UL29473.............................  LDRCZ12301                UL24994................  LQDY6866
UL29473.............................  LDRCZ12308                UL24994................  LQDY6869
UL29473.............................  LDRCZ12316                UL24994................  LQDY6934
UL29473.............................  LDRCZ12319                UL24994................  LQDY6946
UL29473.............................  LQDY6957                  UL24994................  LQDY6963
UL29473.............................  LQDY9075                  UL23166................  LQDY6745
UL29473.............................  LQDY9084                  UL23166................  LQDY6846
UL29473.............................  LQDY9557                  UL23166................  LQDY6848
UL29473.............................  LQDY9906                  UL23166................  LQDY6954
UL29473.............................  LQDY9956                  FK24790................  LDRCZ12492
UL29473.............................  LQDY9970                  FK24790................  LDRCZ12694
UL29473.............................  LQDY9985
----------------------------------------------------------------------------------------------------------------

    (2) For all RB211-524 engine marks except RB211-524D4 variants:
    (i) If the HP turbine disc cycles are greater than 6150 cycles 
since new on the effective date of this AD, inspect the HP turbine 
disc within 500 cycles after the effective date of this AD.
    (ii) If the HP turbine disc cycles are less than 6150 cycles 
since new on the effective date of this AD, inspect the disc by 
whichever is the soonest of the conditions below:
    (A) Prior to reaching 6650 cycles since new. The HP turbine disc 
life at inspection must be greater than 700 cycles since new.
    (B) At next shop visit where the HP turbine rotor is removed 
from the Combustor Outer Case and the HP turbine disc life is 
greater than 700 cycles since new. If a HP turbine disc that meets 
these cyclic life criteria is currently at shop visit, and if, at 
the effective date of this Airworthiness Directive, it has not yet 
been reinstalled into the Combustion Outer Case, then the HP turbine 
disc must be inspected in accordance with the requirements of this 
Airworthiness Directive at the current shop visit.
    (3) For all RB211-524D4 engine mark variants:
    (i) If the HP turbine disc cycles are greater than 5000 cycles 
since new on the effective date of this AD, inspect the HP turbine 
disc within 500 cycles after the effective date of this AD.
    (ii) If the HP turbine disc cycles were less than 5000 cycles 
since new on the effective date of this AD, inspect the HP turbine 
disc by whichever is the soonest of the conditions below:
    (A) Prior to reaching 5500 cycles since new. The HP turbine disc 
life at inspection must be greater than 700 cycles since new.
    (B) At the next shop visit where the HP turbine rotor is removed 
from the Combustor Outer Case and the HP turbine disc life is 
greater than 700 cycles since new. If a HP turbine disc that meets 
these cyclic life criteria is currently at shop visit, and if, at 
the effective date of this Airworthiness Directive, it has not yet 
been reinstalled into the Combustion Outer Case, then the HP turbine 
disc must be inspected in accordance with the requirements of this 
Airworthiness Directive at the current shop visit.
    (4) For all other HP turbine discs specified in the 
Applicability of this Directive but not listed in Table 1 on page 2:
    (i) Inspect the HP turbine disc at next shop visit where the HP 
turbine rotor is removed from the Combustor Outer Case and the HP 
turbine disc life is greater than 700 cycles since new. If a HP 
turbine disc that meets these cyclic life criteria is currently at 
shop visit, and if, at the effective date of this Airworthiness 
Directive, it has not yet been reinstalled into the Combustion Outer 
Case, then the HP turbine disc must be inspected in accordance with 
the requirements of this Airworthiness Directive at the current shop 
visit.
    (ii) If a HP turbine disc has previously passed the inspection 
to Rolls-Royce NMSB 72-C816 or the focused inspection carried out in 
accordance with Rolls-Royce TS594-J Overhaul Process Manual Task 70-
00-00-200-223 at greater than 700 cycles since new, then either of 
these inspections meets the requirements of this Airworthiness 
Directive.

FAA AD Differences

    (g) Wherever the MCAI AD specifies 24 November 2005, this AD 
specifies the effective date of this AD.

Other FAA AD Provisions

    (h) 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

    (i) Refer to the Civil Aviation Authority Airworthiness 
Directive G-2006-0002, dated February 13, 2006, and RR Nonmandatory 
Service Bulletin RB.211-72-AE718, dated January 24, 2006, for 
related information.
    (j) Contact Jason Yang, Aerospace Engineer, Engine Certification 
Office, FAA, Engine & Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: jason.yang@faa.gov; 
telephone (781) 238-7747; fax (781) 238-7199, for more information 
about this AD.

    Issued in Burlington, Massachusetts, on October 17, 2007.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E7-20923 Filed 10-23-07; 8:45 am]

BILLING CODE 4910-13-P
