[Federal Register Volume 71, Number 16 (Wednesday, January 25, 2006)]
[Proposed Rules]
[Pages 4065-4067]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-898]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-23392; Directorate Identifier 2005-NE-47-AD]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce Corporation (Formerly 
Allison Engine Company, Allison Gas Turbine Division, and Detroit 
Diesel Allison) Models 250-C30, 250-C40, and 250-C47 Series Turboshaft 
Engines

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

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for Rolls-Royce Corporation (formerly Allison Engine Company, Allison 
Gas Turbine Division, and Detroit Diesel Allison) (RRC) models 250-C30, 
250-40, and 250-C47 series turboshaft engines. This proposed AD would 
add an additional life limit for third- and fourth-stage turbine 
wheels. This proposed AD results from analysis by RRC of failures of 
third- and fourth-stage turbine wheels. We are proposing this AD to 
prevent loss of power, possible engine shutdown, or uncontained 
failure.

DATES: We must receive any comments on this proposed AD by March 27, 
2006.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     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, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    Contact Rolls-Royce Corporation, P.O. Box 420, Indianapolis, IN 
46206-0420; telephone (317) 230-6400; fax (317) 230-4243, for the 
service information identified in this proposed AD.
    You may examine the comments on this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: John Tallarovic, Aerospace Engineer, 
Chicago Aircraft Certification Office, FAA, 2300 East Devon Avenue, Des 
Plaines, IL 60018-4696; telephone (847) 294-8180; fax (847) 294-7834.

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-2005-23392; 
Directorate Identifier 2005-NE-47-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to http://dms.dot.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 
DOT Web site, anyone can find and read the comments in any of our 
dockets, including 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) or you 
may visit http://dms.dot.gov.

Examining the AD Docket

    You may examine the docket that contains the proposal, any comments 
received and, any final disposition in person at the DOT Docket Office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Office (telephone (800) 647-5227) is located on 
the plaza level of the Department of Transportation Nassif Building at 
the street address stated in ADDRESSES. Comments will be available in 
the AD docket shortly after the Docket Management Facility receives 
them.

Discussion

    Rolls-Royce Corporation investigated and analyzed nine failures of 
third- and fourth-stage turbine wheels, installed in models 250-C30, 
250-40, and 250-C47 series turboshaft engines. The analysis revealed 
that third- and fourth-stage turbine wheels can prematurely fail if 
they are operated too many times in the

[[Page 4066]]

transient overspeed region. This condition, if not corrected, could 
result in loss of power, possible engine shutdown, or uncontained 
engine failure.

Relevant Service Information

    We have reviewed and approved the technical contents of RRC Alert 
Commercial Engine Bulletins (CEBs) No. CEB A-72-3272 (250-C30 series 
engines), No. CEB A-72-5048 (250-C40 series engines), and No. CEB A-72-
6054 (250-C47 series engines), all Revision 1, all dated July 1, 2005 
(combined in one document). These Alert CEBs contain revised transient 
overspeed limit tables, and include the steady-state avoidance range 
and new transient event thresholds. These Alert CEBs also include 
requirements to record events exceeding the ``Event Threshold''.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would require 
recording the number of times the third- and fourth-stage turbine 
wheels enter into the speed range between ``Event Threshold'' and 
``Maximum Overspeed Transient''. This proposed AD would also require 
retiring and replacing third- and fourth-stage turbine wheels that 
accumulate six transient overspeed events based on certain duration and 
speed parameters. The proposed AD would require you to use the service 
information described previously to perform these actions.

Costs of Compliance

    We estimate that this proposed AD would affect 1,300 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 42 work hours per engine to replace the third- and fourth-
stage turbine wheels, and that the average labor rate is $65 per work 
hour. Required parts would cost about $25,000 per engine. We estimate 
that only 10% of all turbine wheel replacements would result from 
operators exceeding the new transient overspeed event limits. Based on 
these figures, we estimate the total potential maximum cost of the 
proposed AD to U.S. operators to be $3,604,900.

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 have 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 that the 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. Would 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. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration 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:

Rolls-Royce Corporation: Docket No. FAA-2005-23392; Directorate 
Identifier 2005-NE-47-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by March 27, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Rolls-Royce Corporation (formerly Allison 
Engine Company, Allison Gas Turbine Division, and Detroit Diesel 
Allison) (RRC) models 250-C30, 250-40, and 250-C47 series turboshaft 
engines. These engines are installed on, but not limited to, Bell 
206L-3, Bell 206L-4, Bell 407, MDHI 369F, MDHI 369FF, MDHI 600N, and 
Sikorsky S-76A helicopters.

Unsafe Condition

    (d) This AD results from analysis by RRC of failures of third- 
and fourth-stage turbine wheels. We are issuing this AD to prevent 
loss of power, possible engine shutdown, or uncontained failure.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.
    (f) Within 30 days after the effective date of this AD, record 
each time the third- and fourth-stage turbine wheels enter into the 
speed range between ``Event Threshold'' and ``Maximum Overspeed 
Transient''. Use paragraph 2.A. through 2.A.(5) of the 
Accomplishment Instructions and the applicable Figures 1 through 5 
of RRC Alert Commercial Engine Bulletins (CEBs) No. CEB A-72-3272, 
No. CEB A-72-5048, and No. CEB A-72-6054, all Revision 1, all dated 
July 1, 2005 (combined in one document) to determine the speed 
range.
    (g) Remove and retire any third-stage turbine wheel or fourth-
stage turbine wheel after the sixth time the wheel enters into the 
speed range between ``Event Threshold'' and ``Maximum Overspeed 
Transient''.

Third- and Fourth-Stage Turbine Wheel Life Limits

    (h) The retirement criteria in this AD are in addition to the 
existing third- and fourth-stage turbine wheel hour and cycle life 
limits. You must retire the wheels when you exceed any published 
life limit (transient speed excursions, hours, or cycles).

Alternative Methods of Compliance

    (i) The Manager, Chicago Aircraft Certification Office, has the 
authority to approve alternative methods of compliance for this AD 
if requested using the procedures found in 14 CFR 39.19.

Related Information

    (j) None.


[[Page 4067]]


    Issued in Burlington, Massachusetts, on January 18, 2006.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E6-898 Filed 1-24-06; 8:45 am]
BILLING CODE 4910-13-P