Airworthiness Directives; Pratt & Whitney Canada Models PW306A and PW306B Turbofan Engines

[Federal Register Volume 66, Number 25 (Tuesday, February 6, 2001)]
[Rules and Regulations]
[Pages 9029-9031]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-3060]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-NE-51-AD; Amendment 39-12103; AD 2001-03-02]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Canada Models PW306A 
and PW306B Turbofan 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 (PWC) models PW306A and PW306B 
turbofan engines. This amendment requires removing compressor rotor 
2nd, 3rd, and 4th stage drum assemblies and impellers from service 
before exceeding new, lower cyclic life limits. This amendment is 
prompted by the results of test analyses that indicate certain 
compressor rotor 2nd, 3rd, and 4th stage drum assemblies and impellers 
do not have full published life. The actions specified in this AD are 
intended to prevent premature cracking of compressor rotor 2nd, 3rd, 
and 4th stage drum assemblies and impellers which could result in an 
uncontained engine failure and damage to the airplane.

[[Page 9030]]


DATES: Effective February 21, 2001. Comments for inclusion in the rules 
docket must be received on or before April 9, 2001.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2000-NE-51-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. 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: Transport Canada (TC), which is the 
airworthiness authority for Canada, recently notified the FAA that an 
unsafe condition may exist on PWC models PW306A and PW306B turbofan 
engines. PWC conducted testing and found indications of crack 
initiations that occurred earlier than expected. As a result of this 
testing, the manufacturer advises that there is a possibility of 
premature failure of compressor rotor 2nd, 3rd, and 4th stage drum 
assemblies part numbers (P/N's) 30B4149-01, 30B4539-01, and 30B4725-01, 
and impellers P/N's 30B4183-01, 30B4494-01, and 30B4564-01. TC has 
issued Airworthiness Directive No. CF-2000-27, dated August 29, 2000, 
in order to ensure the continued airworthiness of these engines in 
Canada.

Bilateral Airworthiness Agreement

    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 (14 CFR 21.29) and 
the applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, TC has kept the FAA informed of the 
situation described above. The FAA has examined the findings of the 
manufacturer, 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.

Required Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design that are 
used on airplanes registered in the United States, this AD is being 
issued to prevent premature cracking of compressor rotor 2nd, 3rd, and 
4th stage drums and impellers. This AD requires a decrease in the 
current life limit of compressor rotor 2nd, 3rd, and 4th stage drum 
assemblies and impellers from 6,000 to 3,000 cycles, and replacement of 
the drums and impellers with serviceable parts. The new life limits are 
based on the manufacturer's test results that indicate that compressor 
rotor 2nd, 3rd, and 4th stage drum assemblies and impellers do not have 
full published lives.

Immediate Adoption

    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 
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. 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 2000-NE-51-AD.'' The postcard will be date stamped and 
returned to the commenter.

Regulatory Impact

    This action 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 
responsibilities among the various levels of government. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this proposal.
    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 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:

2001-03-02  Pratt & Whitney Canada: Amendment 39-12103. Docket No. 
2000-NE-51-AD.

[[Page 9031]]

Applicability

    Pratt & Whitney Canada (PWC) models PW306A and PW306B turbofan 
engines with compressor rotor 2nd, 3rd, and 4th stage drum assembly 
part numbers (P/N's) 30B4149-01, 30B4539-01, and 30B4725-01, and 
impellers P/N's 30B4183-01, 30B4494-01, and 30B4564-01 installed. 
These engines are installed on but not limited to Dornier Luftfahrt 
GmbH 328-300 Jet, and Israel Aircraft Industries, LTD. Galaxy 
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 (d) 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 premature cracking of compressor rotor 2nd, 3rd, and 
4th stage drum assemblies and impellers which could result in an 
uncontained engine failure and damage to the airplane, accomplish 
the following:

Compressor Rotor 2nd, 3rd, and 4th Stage Drum Assembly, and Impeller 
New Life Limit

    (a) Remove compressor rotor 2nd, 3rd, and 4th stage drum 
assembly P/N's 30B4149-01, 30B4539-01, or 30B4725-01, and impeller 
P/N's 30B4183-01, 30B4494-01, or 30B4564-01 before exceeding their 
new life limits in Table 1, and replace with serviceable parts.

                                            Table 1.--New Life Limits
----------------------------------------------------------------------------------------------------------------
                                                                                              Flight      Life
             Engine model                      Part name                Part numbers          count      limit
                                                                                              factor     cycles
----------------------------------------------------------------------------------------------------------------
PW306A...............................  Compressor Rotor 2nd,     30B4149-01                       0.9      3,000
                                        3rd, and 4th Stage Drum  30B4539-01                       0.9      3,000
                                        Assembly.                30B4725-01                       0.9      3,000
                                       Impeller................  30B4183-01                       0.9      3,000
                                                                 30B4494-01                       0.9      3,000
                                                                 30B4564-01                       0.9      3,000
PW306B...............................  Compressor Rotor 2nd,     30B4149-01                       1.0      3,000
                                        3rd, and 4th Stage Drum  30B4539-01                       1.0      3,000
                                        Assembly.                30B4725-01                       1.0      3,000
                                       Impeller................  30B4183-01                       1.0      3,000
                                                                 30B4494-01                       1.0      3,000
                                                                 30B4564-01                       1.0      3,000
----------------------------------------------------------------------------------------------------------------

Use of Flight Count Factor

    (b) For PW306A engines only, multiply number of flights 
(takeoffs and landings) by 0.9 to determine cycles.
Examples:
    3,333 (flights)  x  0.9 (flight count factor) = 3,000 cycles.
    2,850 (flights)  x  0.9 (flight count factor) = 2,565 cycles.
    (c) Except as provided for in paragraph (d) of this AD, do not 
install any part identified by P/N in paragraph (a) of this AD, that 
exceed the new life limit.

Alternative Method of Compliance

    (d) 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

    (e) 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.

Effective Date of This AD

    (f) This amendment becomes effective on February 21, 2001.

    Issued in Burlington, MA, on January 30, 2001.
David A. Downey,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-3060 Filed 2-5-01; 8:45 am]
BILLING CODE 4910-13-P

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