AD 2002-06-08

[Federal Register Volume 67, Number 56 (Friday, March 22, 2002)]
[Rules and Regulations]
[Pages 13262-13264]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 02-6913]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-31-AD; Amendment 39-12685; AD 2002-06-08]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to certain Rolls-Royce Corporation (formerly Allison 
Engine Company) 250-C28 series engines. This amendment requires 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 amendment also establishes a drawdown program to require 
the removal of those turbine wheels that exceed the new lower limits. 
This amendment is prompted by the potential to experience uncommanded 
shutdown caused by fractures of third stage turbine blade tips and 
shrouds. The actions specified by this AD are intended to prevent 
uncommanded shutdown of the engine due to fractures of third stage 
turbine blade tips and shrouds.

DATES: Effective date April 26, 2002.

ADDRESSES: The information contained in this AD may be examined, by 
appointment, at the Federal Aviation Administration (FAA), New England 
Region, Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA; or at the Office of the Federal Register, 800 North 
Capitol Street, NW, suite 700, Washington, DC.

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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that 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 
proposal, was published in the Federal Register on November 8, 2001 (66 
FR 56493). That action proposed to require removal of third stage 
turbine wheels, part number (P/N) 6899383, with SN's, from service 
before exceeding new, reduced life limits. That action also proposed to 
establish a drawdown program to require the removal of those turbine 
wheels that exceed the new lower limit.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Change Life Limits References

    One commenter requests that all references to ``new, reduced 
life'', and ``new lower'' limits be removed and replaced with 
``specified hour and cycle'' limits and ``acceptable hour and cycle'' 
limits.
    The FAA does not agree. The preamble of the AD provides background 
information as to why the AD is being issued. The FAA has only one 
means of mandating lower life limits on a life limited part, and that 
is with an AD. The sole purpose of this AD is to mandate lower life 
limits. Removing references to ``new, reduced life'', and ``new lower'' 
limits in the preamble adds to confusion because those references 
explain why this AD is being issued.

Remove References to Reports of Five Uncommanded Shutdowns

    The manufacturer requests that references to reports of five 
uncommanded shutdowns occurring as a result of the out-of-print 
condition addressed by this AD, be removed. At the time this AD action 
was first being considered, it was preliminarily reported that there 
were five uncommanded shutdowns occurring as a result of the out-of-
print condition addressed by this AD. It has since been determined that 
those shutdowns did not have the out-of-print condition and are 
unrelated to the actions required by this AD. The manufacturer still 
supports the issuance of this AD because of the potential safety issue 
that remains.
    The FAA agrees. Therefore, the summary in the preamble of this 
final rule is changed to read: ``This amendment is prompted by the 
potential to experience uncommanded shutdown caused by third stage 
turbine blade tip fractures, and turbine shroud fractures.''

Eliminate Potential Nomenclature Confusion

    The manufacturer requests that the phrase ``third stage turbine 
shrouds'' be replaced with the word ``shrouds'' and remove reference to 
turbine shroud fractures, to eliminate potential nomenclature 
confusion. The reason for the request is that on the model 250-C28 
series third stage turbine wheels, the blades and shrouds are cast 
together with the hub, creating a one piece unit.
    The FAA agrees. Therefore, the summary in the preamble of this 
final rule is changed to read: ``This amendment is prompted by the 
potential to experience uncommanded shutdown caused by fractures of 
third stage turbine blade tips and shrouds.

[[Page 13263]]

The actions specified by this AD are intended to prevent uncommanded 
shutdown of the engine due to fractures of third stage turbine blade 
tips and shrouds.''

Change Unsafe Condition Wording

    One commenter requests that the NPRM preamble wording found in the 
FAA's Determination of an Unsafe Condition and Proposed Actions 
paragraph be changed from: ``Since an unsafe condition has been 
identified that is likely to exist. * * *'', to ``Since an unsafe 
condition has been identified that may exist. * * *'' No justification 
was given for this change.
    The FAA does not agree. AD's are issued under Part 39 of the 
Federal Aviation Regulations, 14 CFR part 39. The FAA must make a 
finding that an unsafe condition prompting the AD ``is likely to'' 
exist or develop in other products of the same type design.

Incorporate Additional Information

    The manufacturer requests that a phrase be added to the Economic 
Analysis that states that not all affected third stage turbine wheels 
may be installed in engines.
    The FAA agrees that additional information should be added to the 
Economic Analysis. Therefore, the Economic Analysis is modified to 
include the sentence: ``There are approximately 84 engines worldwide 
that may have an affected third stage turbine wheel installed, however, 
it is not known how many of those third stage turbine wheels are 
installed in engines.''

Add Reference to Rolls-Royce Service Bulletin

    The manufacturer requests a clarification to the AD to include a 
reference to the Rolls-Royce Corporation service bulletin associated 
with this life limit change.
    The FAA does not agree. There is no reason to reference the service 
bulletin because all the pertinent information regarding the new 
reduced life limits of the affected third stage turbine wheels, which 
includes part number, serial numbers, and drawdown schedule, are 
included in the AD.

Reword Discussion Information

    One commenter requests changing in the discussion section the 
phrase `` to life limits of 1,500 hours TSN and 3,000 CSN'' to ``to 
life limits of 1,500 hours TSN or 3,000 CSN, whichever occurs first.'' 
This change request by the commenter would be appropriate if the intent 
of this section was to describe how to comply with the new reduced life 
limits. However, the intent of the discussion section is to provide 
background information on the various life limits and how they are 
changing relative to each other. Details on compliance are explained in 
Table 2 of the compliance section of the AD, in which the phrase 
``whichever occurs earlier'' is used where appropriate, consistent with 
the commenter's intent.

Restructure Contents of Table 2

    One commenter requests the restructuring of the contents of Table 2 
in the AD.
    The FAA does not agree. The information in Table 2 as published in 
the NPRM is accurate and concise, and therefore remains unchanged in 
this AD.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.

Economic Analysis

    There are approximately 84 third stage turbine wheels 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 AD. However, it is not known how many of those third stage turbine 
wheels are installed in engines. It would take approximately 44 work 
hours per engine to remove and replace an affected turbine wheel. The 
average labor rate is $60 per work hour. The cost of a new third stage 
turbine wheel is approximately $4,371. The FAA estimates that 
approximately $2,929 per wheel has been lost due to life reduction. 
However, the manufacturer has stated it may reduce the new wheel cost 
to the customer. Based on these figures, the total cost of the AD on 
U.S. operators is estimated to be $294,462.

Regulatory Analysis

    This final 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 final rule.
    For the reasons discussed above, I certify that this action (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 final evaluation has been prepared for 
this action and it 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.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

2002-06-08  Rolls-Royce Corporation: Amendment 39-12685. 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:


          Table 1.--SN's of Affected Third Stage Turbine Wheels
 
 
------------------------------------------------------------------------
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

[[Page 13264]]

 
HX91483R                 HX91527R                 HX91765R
HX91485R                 HX91528R                 HX91766R
HX91486R                 HX91529R                 HX91767R
HX91487R                 HX91530R                 HX91768R
HX91488R                 HX91706R                 HX91769R
------------------------------------------------------------------------
Note.--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
------------------------------------------------------------------------
 For third stage 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 additional 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.
------------------------------------------------------------------------

    (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 in Table 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 with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the aircraft to a location where the 
requirements of this AD can be done.

Effective Date

    (e) This amendment becomes effective on April 26, 2002.

    Issued in Burlington, Massachusetts, on March 14, 2002.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 02-6913 Filed 3-21-02; 8:45 am]
BILLING CODE 4910-13-P