[Federal Register Volume 59, Number 21 (Tuesday, February 1, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-2177]


[[Page Unknown]]

[Federal Register: February 1, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-ANE-04; Amendment 39-8808; AD 94-03-02]

 

Airworthiness Directives; Pratt & Whitney Canada PW100 Series 
Turboprop Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule, request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to Pratt & Whitney Canada PW100 series turboprop engines. 
This action requires a life limit reduction for affected high pressure 
turbine (HPT) disks, and establishes a drawdown schedule for disks 
currently near, at, or greater than the new reduced service life. This 
amendment is prompted by reports of two HPT disk failures, one of which 
was uncontained. The actions specified in this AD are intended to 
prevent an uncontained HPT disk failure and damage to the aircraft.

DATES: Effective February 16, 1994.
    Comments for inclusion in the Rules Docket must be received on or 
before April 4, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-04, 12 New England 
Executive Park, Burlington, MA 01803-5299.
    The service information referenced in this AD may be obtained from 
Pratt & Whitney Canada, 1000, Marie-Victorin, Longueuil, Quebec, Canada 
J4G 1A1. This information may be examined at the FAA, New England 
Region, Office of the Assistant Chief Counsel, 12 New England Executive 
Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Marc Bouthillier, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7135, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: Transport Canada, which is the airworthiness 
authority for Canada, recently notified the Federal Aviation 
Administration (FAA) that an unsafe condition may exist on Pratt & 
Whitney Canada (PWC) Model PW118, PW118A, PW120, PW120A, PW121, PW123, 
PW124B, and PW125B turboprop engines. Transport Canada advises that 
they have received reports of two high pressure turbine (HPT) disk 
failures in the rim region with subsequent inflight engine shutdowns. 
Both disks failed at the same location in low cycle fatigue. One event 
was fully contained within the engine casings; the second event 
liberated some small debris through the engine nacelle.
    Transport Canada issued AD CF-94-XX, dated January XX, 1994, in 
order to assure the airworthiness of these PWC PW100 series turboprop 
engines in Canada.
    This engine model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
Section 21.29 of the Federal Aviation Regulations 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.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other PWC PW100 series turboprop engines of the 
same type design registered in the United States, the proposed AD would 
require a life limit reduction for affected HPT disks, and establishes 
a drawdown schedule to manage disks currently near, at, or greater than 
the new reduced service life, without significant effect on flight 
safety or economic factors. The FAA has determined that a reduction in 
cyclic life limit, based on demonstrated crack initiation and 
propagation rates, would minimize the possibility of a disk failure, 
and restore the level of safety required at the time of type 
certification.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ``ADDRESSES.'' 
All communications received on or before the closing date for comments 
will be considered, and this rule may be amended in light of the 
comments received. Factual information that supports the commenter's 
ideas and suggestions is extremely helpful in evaluating the 
effectiveness of the AD action and determining whether additional 
rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD 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 94-ANE-04.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, may 
be obtained from 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 14 CFR part 
39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [AMENDED]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

94-03-02 Pratt & Whitney Canada: Amendment 39-8808. Docket 94-ANE-
04.
    Applicability: Pratt & Whitney Canada (PWC) Model PW118, PW118A, 
PW120, PW120A, PW121, PW123, PW124B, and PW125B turboprop engines, 
installed on but not limited to Dehavilland DHC-8 series, Embraer 
EMB-120 series, ATR-42 and -72 series, Fokker 50 series, Canadair 
Models CL-215T and 415, Dornier 328 series, British Aerospace ATP 
series, and XAC Y7-200A aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent an uncontained HPT disk failure and damage to the 
aircraft, accomplish the following:
    (a) Remove from service high pressure turbine (HPT) disks, part 
numbers (P/N) 3035711 and 3038411, and replace with a serviceable 
part in accordance with the following schedule, based on cycles in 
service (CIS) on the effective date of this airworthiness directive 
(AD):
    (1) For disks with 13,000 or more CIS, remove within the next 
1,000 CIS after the effective date of this AD, but not to exceed 
15,000 total CIS.
    (2) For disks with 12,000 or more CIS, but less than 13,000 CIS, 
remove within the next 1,250 CIS, but not to exceed 14,000 total 
CIS.
    (3) For disks with 10,000 or more CIS, but less than 12,000 CIS, 
remove within the next 1,750 CIS, but not to exceed 13,250 total 
CIS.
    (4) For disks with 8,000 or more CIS, but less than 10,000 CIS, 
remove within the next 2,500 CIS, but not to exceed 12,000 total 
CIS.
    (5) For disks with less than 8,000 CIS, remove at or prior to 
accumulating 10,000 total CIS.
    (b) This AD establishes a new service cycle life limit for HPT 
disks, P/N 3035711 and 3038411, of 10,000 total CIS.

    Note: Further information on the life limit reduction for 
affected HPT disks can be found in PWC Service Information Letter 
No. 307, dated December 17, 1993.

    (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, Engine Certification Office. The 
request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office.

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

    (d) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the aircraft to a location where the 
requirements of this AD can be accomplished.
    (e) This amendment becomes effective on February 16, 1994.

    Issued in Burlington, Massachusetts, on January 24, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-2177 Filed 1-31-94; 8:45 am]
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