[Federal Register Volume 66, Number 217 (Thursday, November 8, 2001)]
[Proposed Rules]
[Pages 56493-56495]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-28025]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-31-AD]
RIN 2120-AA64


Airworthiness Directives; Rolls-Royce Corporation (Formerly 
Allison Engine Company) 250-C28 Series Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration (FAA) proposes to adopt a 
new airworthiness directive (AD) that is applicable to certain Rolls-
Royce Corporation (formerly Allison Engine Company) 250-C28 series 
engines. This proposal would require removal of third stage turbine 
wheels, part number (P/N) 6899383, with certain serial numbers (SN's), 
from service before exceeding new, reduced life limits. This proposal 
would also establish a drawdown program to require the removal of those 
turbine wheels that exceed the new lower limit. This proposal is 
prompted by five reports of uncommanded shutdown caused by third stage 
turbine blade tip fractures, and turbine shroud fractures. The actions 
specified by the proposed AD are intended to prevent uncommanded 
shutdown of the engine due to fractures of third stage turbine blade 
tips and third stage turbine shrouds.

DATES: Comments must be received by January 7, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

[[Page 56494]]

Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No.2001-NE-31-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. Comments may also be sent via 
the Internet using the following address: ``[email protected]''. 
Comments sent via the Internet must contain the docket number in the 
subject line.

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

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NE-31-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2001-NE-31-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    The FAA has received reports of five uncommanded shutdowns on 
Rolls-Royce Corporation 250-C28 series engines, caused by third stage 
turbine blade tip and turbine shroud fractures. The manufacturer's 
analysis indicates that this condition is caused by certain third stage 
turbine wheels, part number (P/N) 6899383, that have a critical 
dimension outside the manufacturing limit. There are believed to be 84 
third stage turbine wheels with this condition. For these 84 turbine 
wheels, the manufacturer has reduced the life limits of 4,550 hours 
time-since-new (TSN) and 6,000 cycles-since-new (CSN), to life limits 
of 1,500 hours TSN and 3,000 CSN. This condition, if not corrected, 
could result in an uncommanded shutdown of the engine due to fractures 
of third stage turbine blade tips and third stage turbine shrouds.

Proposed Requirements of This AD

    Since an unsafe condition has been identified that is likely to 
exist or develop on other Rolls-Royce Corporation 250-C28 series 
engines of the same type design, the proposed AD would require removal 
from service certain SN's of third stage turbine wheels before 
exceeding new, reduced life limits.

Economic Analysis

    There are approximately 84 engines of the affected design in the 
worldwide fleet. The FAA estimates that 42 engines installed on 
helicopters of U.S. registry would be affected by this proposed AD. The 
FAA also estimates that it would take approximately 44 work hours per 
engine to accomplish the proposed actions, and that the average labor 
rate is $60 per work hour. The cost of a new third stage turbine wheel 
is approximately $4,371. Although the FAA estimates that approximately 
$2,929 per wheel has been lost due to life reduction, the manufacturer 
has stated it may reduce the new wheel cost to the customer. Based on 
these figures, the total cost effect of the proposed AD on U.S. 
operators is estimated to be $294,462.

Regulatory Analysis

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it 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. 
Accordingly, the FAA has not consulted with state authorities prior to 
publication of this proposed rule.
    For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new 
airworthiness directive:

Rolls-Royce Corporation: Docket No. 2001-NE-31-AD.

Applicability

    This airworthiness directive (AD) is applicable to Rolls-Royce 
Corporation (formerly Allison Engine Company) 250-C28, -C28B, and -
C28C model engines with third stage turbine wheels part number (P/N) 
6899383, listed by serial number (SN) in the following Table 1:

[[Page 56495]]



                              Table 1.--SN's of Affected Third Stage Turbine Wheels
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                     HX91428R                              HX91489R                              HX91707R
                     HX91456R                              HX91490R                              HX91708R
                     HX91457R                              HX91492R                              HX91709R
                     HX91458R                              HX91493R                              HX91710R
                     HX91459R                              HX91494R                              HX91711R
                     HX91461R                              HX91500R                              HX91712R
                     HX91462R                              HX91501R                              HX91713R
                     HX91464R                              HX91503R                              HX91714R
                     HX914659                              HX91504R                              HX91715R
                     HX91465R                              HX91506R                              HX91721R
                     HX91466R                              HX91507R                              HX91722R
                     HX91467R                              HX91508R                              HX91726R
                     HX91468R                              HX91510R                              HX91733R
                     HX91469R                              HX91511R                              HX91735R
                     HX91471R                              HX91512R                              HX91736R
                     HX91472R                              HX91513R                              HX91738R
                     HX91473R                              HX91519R                              HX91742R
                     HX91474R                              HX91520R                              HX91744R
                     HX91475R                              HX91522R                              HX91748R
                     HX91477R                              HX91523R                              HX91749R
                     HX91478R                              HX91524R                              HX91750R
                     HX91480R                              HX91525R                              HX91754R
                     HX91482R                              HX91526R                              HX91764R
                     HX91483R                              HX91527R                              HX91765R
                     HX91485R                              HX91528R                              HX91766R
                     HX91486R                              HX91529R                              HX91767R
                     HX91487R                              HX91530R                              HX91768R
                     HX91488R                              HX91706R                              HX91769R
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    These engines are installed on, but not limited to Bell 
Helicopter Textron 206L-1 helicopters.

    Note 1: This AD applies to each engine identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For engines that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

Compliance

    Compliance with this AD is required as indicated, unless already 
done.
    To prevent an uncommanded shutdown of the engine due to 
fractures of third stage turbine blade tips and third stage turbine 
shrouds, do the following:
    (a) Remove from service the third stage turbine wheels, P/N 
6899383, listed by SN in Table 1 of this AD, in accordance with the 
following Table 2:

                       Table 2.--Removal Schedule
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  For third stage by turbine wheels on
     the effective date of this AD                  Remove by
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(1) With fewer than 3,000 cycles-since-  3,000 CSN or 1,500 hours TSN,
 new (CSN), and fewer than 1,500 hours    whichever occurs earlier.
 time-since-new (TSN).
(2) With between 3,000 and 6,000 CSN,    200 additional cycles, after
 and fewer than 1,500 hours TSN.          the effective date of this AD.
(3) With fewer than 3,000 CSN, and       100 additional hours, after the
 between 1,500 and 3,000 hours TSN.       effective date of this AD.
(4) With between 3,000 and 6,000 CSN     200 additionally cycles or 100
 and between 1,500 and 3,000 hours TSN.   additional hours, after the
                                          effective date of this AD,
                                          whichever occurs earlier.
(5) With more than 6,000 CSN, or more    Before further flight.
 than 3,000 hours TSN.
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    (b) After the effective date of this AD, do not install any 
third stage turbine wheels listed by SN in Table 1 of this AD. 
Thereafter, except as provided in paragraph (c) of this AD, no 
alternative cyclic life limits may be approved for the turbine 
wheels listed inTable 1 of this AD.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Chicago Aircraft Certification 
Office (ACO). Operators must submit their request through an 
appropriate FAA Principal Maintenance Inspector, who may add 
comments and then send it to the Manager, Chicago ACO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Chicago ACO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the helicopter to a location where the 
requirements of this AD can be done.

    Issued in Burlington, Massachusetts, on November 1, 2001.
Diane S. Romanosky,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-28025 Filed 11-7-01; 8:45 am]
BILLING CODE 4910-13-U