Airworthiness Directives; Pratt & Whitney Canada PT6A-25C and -114A Series Turboprop Engines

[Federal Register Volume 66, Number 190 (Monday, October 1, 2001)]
[Rules and Regulations]
[Pages 49823-49824]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-24270]



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Federal Register / Vol. 66, No. 190 / Monday, October 1, 2001 / Rules 
and Regulations

[[Page 49823]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-26-AD; Amendment 39-12447; AD 2001-20-01]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Canada PT6A-25C and -
114A Series Turboprop Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Pratt & Whitney Canada (PWC) PT6A-25C and -114A turboprop 
engines. This amendment will require initial and repetitive visual 
inspections, and eventual replacement of the compressor bleed valve 
assembly, with a redesigned valve assembly for -114A and -25C engines. 
This amendment is prompted by reports of two occurrences of uncommanded 
engine power loss. The actions specified by this AD are intended to 
detect wear in the compressor bleed valve assembly which may cause 
valve orifice blockage, resulting in a loss of power, an inability to 
accelerate the engine, and an in-flight shutdown.

DATES: Effective date November 5, 2001. The incorporation by reference 
of certain publications listed in the regulations is approved by the 
Director of the Federal Register as of November 5, 2001.

ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney Canada, 1000 Marie-Victorin, Longueuil, 
Quebec, Canada J4G1A1. This information may be examined at the 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: James Rosa, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone: (781) 
238-7152; fax: (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to PWC PT6A-25C and -114A turboprop 
engines, was published in the Federal Register on September 20, 2000 
(65 FR 56819). That action proposed to require initial and repetitive 
visual inspections, and eventual replacement of the compressor bleed 
valve assembly, with a redesigned valve assembly for -114A engines, and 
-25C engines.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Comments Received Regarding Terminating Action

    Three commenters request that the FAA add PWC Service Bulletin (SB) 
PT6A-72-1581, Revision 1, dated February 1, 2000, as terminating action 
for the AD. The FAA agrees. The service bulletin referenced in the 
proposal, PWC SB PT6A-72-1588, and PWC SB PT6A-72-1581, Revision 1, 
introduce the same part, a new design of compressor bleed valve 
assembly that eliminates the unsafe condition. Therefore, either PWC SB 
PT6A-72-1581 or PWC SB PT6A-72-1588, dated February 18, 2000, will 
serve as terminating action for PT6A-114A to the inspection 
requirements of this AD.

Comment Regarding the Applicability of the AD

    One comment notes that all of the referenced service bulletins 
apply to the PT6A-25C and PT6A-114A engines only if those engines have 
incorporated SB PT6A-72-1510. The comment, therefore, asks that the FAA 
limit the applicability of this AD to just those engines that have 
incorporated SB PT6A-72-1510.
    The FAA agrees. Only those engines that were modified per SB PT6A-
72-1510 should be affected by this AD, which has been changed 
accordingly.

Differences Between the NPRM and AD

    Since the publication of the NPRM, Pratt and Whitey has published 
PWC SB PT6A-72-1589, dated November 1, 2000. This SB provides for 
inspection and replacement of compressor bleed valve assemblies 
installed on PT6A-25C series turboprop engines at the next shop visit, 
but no later than five years from the effective date of this AD. 
Replacement of the compressor bleed valve assembly is considered 
terminating action for the inspection requirements of this AD.

Economic Impact

    There are about 504 engines of the affected design in the worldwide 
fleet. The FAA estimates that 353 engines installed on aircraft of U.S. 
registry would be affected by this AD, that it would take about two 
work hours per engine to accomplish the initial inspections, and one 
hour to accomplish the replacement of the valve, and that the average 
labor rate is $60 per work hour. Required parts would cost about 
$7,458.00 per engine. Based on these figures, the total cost impact of 
the AD on U.S. operators is estimated to be $2,696,214.

Regulatory Impact

    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

[[Page 49824]]

Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, 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:

2001-20-01 Pratt & Whitney Canada: Amendment 39-12447. Docket 2000-
NE-26-AD.

Applicability

    This airworthiness directive (AD) applies to PT6A-25C and -114A 
Series turboprop engines, that have incorporated P&WC S.B. 1510, 
which are installed on but not limited to Pilatus PC-7 and Cessna 
208 Caravan airplanes.

    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 (f) 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 detect wear on the compressor bleed valve assembly cover, 
guide pin shaft, cotter pin, and to detect particles from diaphragm 
wear, which may cause valve orifice blockage, resulting in a loss of 
power, an inability to accelerate the engine, and an in-flight 
shutdown, do following:

Initial and Repetitive Inspections

    (a) Perform an initial visual inspection of the compressor bleed 
valve assembly components within 150 flight hours after the 
effective date of this AD in accordance with Accomplishment 
Instructions, Section 3A through 3B of Pratt & Whitney Canada (PWC) 
Service Bulletin (SB) PT6A-72-1574, Revision 2, dated October 14, 
1999.
    (b) Thereafter, perform repetitive visual inspections of the 
compressor bleed valve assembly components within 600 flight hours 
after the last inspection in accordance with Accomplishment 
Instructions, Section 3A through 3B of PWC SB PT6A-72-1574, Revision 
2, dated October 14, 1999.

Terminating Action

    (c) For PT6A-114A series turboprop engines, replacement of 
compressor bleed valve assemblies at the next shop visit, with the 
redesigned valve assembly, in accordance with PWC SB PT6A-72-1588, 
dated February 18, 2000 or PWC SB PT6A-72-1581, Revision 1, dated 
February 1, 2000, is considered terminating action for the 
inspection requirements of this AD. This action must be done at the 
next shop visit but no later than five years from the effective date 
of this AD.
    (d) For PT6A-25C series turboprop engines, replacement of 
compressor bleed valve assemblies with the redesigned valve 
assembly, at the next shop visit, in accordance with PWC SB PT6A-72-
1589, dated November 1, 2000, is considered terminating action for 
the inspection requirements of this AD. This action must be done at 
the next shop visit but no later than five years from the effective 
date of this AD.

Definition

    (e) For the purpose of this AD, a shop visit is defined as when 
the subassembly (i.e. module, accessories, components or build 
groups) is disassembled and access is available to the compressor 
bleed valve assembly.

Alternative Methods of Compliance

    (f) 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, Engine Certification Office (ECO). 
Operators shall submit their request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

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

Special Flight Permits

    (g) 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 airplane to a location where the 
requirements of this AD can be accomplished.

Documents That Have Been Incorporated by Reference

    (h) The inspections and replacement shall be done in accordance 
with the following Pratt & Whitney Canada service bulletins:

----------------------------------------------------------------------------------------------------------------
            Document No.                      Pages                 Revision                     Date
----------------------------------------------------------------------------------------------------------------
SB PT6A-72-1574....................  All...................  2.....................  Oct. 14, 1999.
    Total pages: 3
SB PT6A-72-1581....................  All...................  1.....................  Feb. 1, 2000.
    Total pages: 12
SB PT6A-72-1588....................  All...................  Original..............  Feb. 18, 2000.
    Total pages:12
SB PT6A-72-1589....................  All...................  Original..............  Nov. 1, 2000.
    Total pages: 10
----------------------------------------------------------------------------------------------------------------

This incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from Pratt & Whitney Canada, 1000 Marie-
Victorin, Longueuil, Quebec, Canada J4G1A1. Copies may be inspected 
at the 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.

    Note 3: The subject of this AD is addressed in Transport Canada 
Airworthiness Directive CF-99-23, dated September 14, 1999.

Effective Date

    (i) This amendment becomes effective on November 5, 2001.

    Issued in Burlington, Massachusetts, on September 20, 2001.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 01-24270 Filed 9-28-01; 8:45 am]
BILLING CODE 4910-13-P

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