[Federal Register Volume 65, Number 222 (Thursday, November 16, 2000)]
[Proposed Rules]
[Pages 69258-69259]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-29379]


 ========================================================================
 Proposed Rules
                                                 Federal Register
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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  Federal Register / Vol. 65, No. 222 / Thursday, November 16, 2000 / 
Proposed Rules  

[[Page 69258]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-24-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Canada (P&WC) Model 
PW305 and PW305A Turbofan 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) 
Model PW305 and PW305A turbofan engines. This proposal would require 
removing stage 4 low pressure turbine (LPT) disks from service before 
exceeding new, lower cyclic life limits. This proposal is prompted by 
the results of a spin pit test analysis which indicate that the stage 4 
LPT disk does not have full published life. The actions specified by 
the proposed AD are intended to prevent LPT disk failure resulting from 
premature cracking of the LPT disks, which could result in an 
uncontained engine failure and damage to the airplane.

DATES: Comments must be received by December 18, 2000.

ADDRESSES: Submit comments to the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 2000-NE-24-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.
    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:

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 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 2000-NE-24-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-24-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    Transport Canada, which is the airworthiness authority for Canada, 
recently notified the FAA that an unsafe condition may exist on P&WC 
model PW305 and PW305A turbofan engines. P&WC ran a spin test and found 
earlier than expected indications of crack initiation. As a result of 
this test, Transport Canada advises that there is a possibility of 
premature failure of the stage 4 LPT disks, part numbers (P/N's) 
30A1457 and 30A1499. This condition, if not corrected, could cause a 
failure of the stage 4 LPT disk, that could result in an uncontained 
engine failure and damage to the airplane. To prevent a premature 
failure of the stage 4 LPT disk, this proposal would decrease the 
current life limit of these disks from 5,000 to 4,000 cycles-in-service 
(CIS).

Bilateral Airworthiness Agreement

    This engine model is manufactured in Canada and is type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation 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. To prevent 
premature failure of the stage 4 LPT disk used in the model PW305 and 
PW305A engines, Transport Canada issued airworthiness directive (AD) 
CF-99-28 in order to ensure the airworthiness of these P&WC engines in 
Canada.

Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require removing certain stage 4 LPT disk P/N's 
30A1457 and 30A1499 from service, before exceeding new lower cyclic 
life limit of 4000 CIS, and replacing them with serviceable parts. The 
new life limits are based on spin test analysis results that indicate 
that the LPT disks do not have full published lives.

Economic Analysis

    There are currently 358 engines in the domestic fleet containing 
the affected stage 4 LPT disks, P/N's 30A1457 and

[[Page 69259]]

30A1499, and a total of 484 engines in the worldwide fleet. The total 
cost to the domestic fleet to remove and replace these disks at the new 
life limit of 4000 CIS, rather than the former life limit of 5000 CIS, 
is estimated to be $6,331,015.

Regulatory Impact

    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:

Pratt & Whitney Canada: Docket No. 2000-NE-24-AD.
    Applicability: Pratt & Whitney Canada (P&WC) Model PW305 and 
PW305A turbofan engines, with stage 4 low pressure turbine (LPT) 
disks, part numbers (P/N's) 30A1457 and 30A1499. These engines are 
installed on but not limited to British Aerospace BAe. 125 1000A, 
BAe. 125 1000B, Hawker 1000 and Learjet 60 series airplanes.

    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 (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: Required as indicated, unless accomplished 
previously.
    To prevent premature LPT disk failure due to cracking of the LPT 
disks, which could result in an uncontained engine failure and 
damage to the airplane, accomplish the following:

New Stage 4 LPT Life Limit

    (a) Remove stage 4 LPT disks, P/N's 30A1457 and 30A1499, prior 
to exceeding the new life limit of 4000 cycles-in-service (CIS).
    (b) Except for the provisions of paragraph (c) of this AD, no 
parts, identified by P/N in paragraph (a) of this AD, that exceed 
the new life limit of 4000 CIS, may be installed.

Alternative Method 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, 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.

Ferry Flights

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

    Issued in Burlington, MA, on November 9, 2000.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-29379 Filed 11-15-00; 8:45 am]
BILLING CODE 4910-13-U