[Federal Register Volume 65, Number 183 (Wednesday, September 20, 2000)]
[Proposed Rules]
[Pages 56819-56821]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-24114]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-26-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to Pratt & Whitney Canada (P&WC) 
PT6A-25C and -114A turboprop engines. This proposal would require 
initial and repetitive visual inspections, and eventual replacement of 
the compressor bleed valve assembly, with a redesigned valve assembly 
for the -114A engines, and initial and repetitive visual inspections 
only for -25C engines. This proposal is prompted by reports of two 
occurrences of uncommanded engine power loss. The actions specified by 
the proposed AD are intended to detect wear in the compressor bleed 
valve assembly which may cause valve orifice blockage, resulting in a 
loss of power, inability of engine acceleration, and in-flight shut 
down.

DATES: Comments must be received by November 20, 2000.

ADDRESSES: Submit comments to the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 2000-NE-26-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299. 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. 
Comments may be inspected at this location between 8:00 a.m. and 4:30 
p.m., Monday through Friday, except Federal holidays.
    The service information referenced in the proposed rule 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.

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: This proposal would require initial and 
repetitive visual inspections, and replacement if necessary, of certain 
compressor bleed valve assembly components on PT6A-25C and -114A 
turboprop engines, in accordance with P&WC Service Bulletin (SB) No. 
1574 Revision 2, dated October 14, 1999. This proposal would also 
require eventual replacement of compressor bleed valve assemblies with 
redesigned valve assemblies, on PT6A-114A turboprop engines, in 
accordance with P&WC SB No. 1588, dated February 18, 2000.

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 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 notice 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 notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2000-NE-26-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. 2000-NE-26-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    Transport Canada (TC), which is the airworthiness authority for 
Canada, recently notified the FAA that an unsafe condition may exist on 
P&WC PT6A-25C and -114A series turboprop engines, which are installed 
on but not limited to Pilatus PC-7 and Cessna 208 Caravan airplanes. TC 
advises that engines, which have incorporated P&WC SB No. 1510, may 
experience cotter pin and diaphragm wear and fatigue inside the 
compressor bleed valve assembly. Separation of sections of the cotter 
pin and particles from diaphragm wear may cause blockage of one or both 
valve orifices, resulting in a power loss, inability of the engine to 
accelerate and/or in-flight shut down. P&WC has issued SB No. 1574, 
Revision 2, dated October 14, 1999, which specifies initial visual 
inspection of compressor bleed valve assembly cover, guide pin shaft, 
cotter pin, and diaphragm for wear, and, replacement of these parts if 
necessary. TC classified this SB as mandatory by issuing AD No. CF-99-
23, dated September 14, 1999 in order to assure the continued 
airworthiness of these airplanes in Canada. P&WC has also issued SB No. 
1588, dated February 18, 2000, for PT6A-114A turboprop engines that 
specify compressor bleed valve assembly replacement with a redesigned 
valve assembly.

[[Page 56820]]

Bilateral Airworthiness Agreement

    These engine models are manufactured in Canada and are type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of Title 14 of the Code of Federal Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement. Pursuant 
to this bilateral airworthiness agreement, Transport Canada has kept 
the FAA informed of the situation described above. The FAA has examined 
the findings of Transport Canada, reviewed all available information, 
and determined that AD action is necessary for products of this type 
design that are certificated for operation in the United States.

Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design registered in 
the United States, the proposed AD would require initial visual 
inspection of certain compressor bleed valve assembly components within 
150 flight hours after the effective date of this AD, repetitive visual 
inspections within 600 flight hours after the last inspection, and if 
necessary, the replacement of certain components. The proposed AD would 
also require replacement of compressor bleed valve assemblies on PT6A-
114A engines which have had Pratt & Whitney Canada SB No. 1510 
incorporated, with a redesigned valve assembly at the next shop visit 
but no later than five years after the effective date of this AD. The 
actions would be required to be accomplished in accordance with the 
SB's described previously.

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 proposed AD, that it would take 
about 2 work hours per engine to accomplish the initial inspections, 
and 1 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 proposed AD on U.S. operators is estimated to be 
$2,696,214.00.

Regulatory Impact

    This proposal 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 proposal.
    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:

Pratt & Whitney Canada: Docket No. 2000-NE-26-AD.

    Applicability: This airworthiness directive (AD) applies to 
PT6A-25C and -114A Series turboprop engines, installed on but not 
limited to the following airplanes: Pilatus PC-7, Cessna 208 
Caravan.

    Note 1: This airworthiness directive (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 (e) 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: Required as indicated, unless accomplished 
previously.

Initial and Repetitive Inspections

    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 blockage of one or both valve orifices, 
resulting in a loss of power, inability of the engine to accelerate, 
and/or in-flight shut down, accomplish the following:
    (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 (P&WC) 
Service Bulletin (SB) No. 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 Pratt & Whitney Canada (P&WC) 
Service Bulletin (SB) No. 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 P&WC SB No. 1588, 
dated February 18, 2000, is considered terminating action for the 
repetitive inspection. This action must be done at the next shop 
visit but no later than five years from the effective date of this 
AD.

Definition

    (d) 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

    (e) 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

    (f) Special flight permits may be issued in accordance with 
sections 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 accomplished.


[[Page 56821]]


    Issued in Burlington, Massachusetts, on September 13, 2000.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-24114 Filed 9-19-00; 8:45 am]
BILLING CODE 4910-13-P