[Federal Register Volume 59, Number 120 (Thursday, June 23, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-15011]


[[Page Unknown]]

[Federal Register: June 23, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-ANE-47; Amendment 39-8927; AD 94-11-11]

 

Airworthiness Directives; Pratt & Whitney Canada PW100 Series 
Turboprop Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to Pratt & Whitney Canada PW100 series turboprop 
engines, that currently requires rework or replacement of the 
intercompressor case (ICC), and replacement of the low pressure rotor 
speed (NL) sensor port sealing tube and the external air tube 
connecting the P2.5/P3 switching valve to the rear inlet case. This 
amendment additionally requires installation of an airflow deflector 
bracket nozzle assembly, or modification of the No. 5 bearing pressure 
air system. Finally, this action requires installation of a No. 5 
bearing vent tube assembly and allows extension of the compliance 
interval for reworking or replacing the ICC. This amendment is prompted 
by the development of additional hardware that will further reduce the 
risk of internal oil fires in the ICC. The actions specified by this AD 
are intended to prevent fire in the engine ICC and nacelle cavities, 
inflight engine shutdown, and aircraft damage.

DATES: Effective July 25, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 25, 1994.
ADDRESSES: The service information referenced in this AD may be 
obtained from Pratt & Whitney Canada, Technical Publications 
Department, 1000 Marie Victorin, Longueuil, Quebec J4G 1A1. This 
information may be examined at the Federal Aviation Administration 
(FAA), New England Region, Office of the Assistant Chief Counsel, 12 
New England Executive Park, Burlington, MA 01803-5299; or at the Office 
of the Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.

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) PW118A, PW123, PW124B, PW125B, and PW126A 
turboprop engines. Transport Canada advises that they have received 
reports of internal oil fires in the intercompressor case (ICC). There 
have been 13 ICC fire events due to ignition of oil that had 
accumulated in the P2.5 air cavity. The ICC fire melts the brazing on 
the external air-tube connected to the P2.5/P3 switching-valve, and on 
the low pressure rotor speed (NL) sensor port sealing tube, allowing 
both to disengage. The ICC fire then migrates into the engine nacelle 
cavity resulting in inflight engine shutdown and potential aircraft 
damage.
    On December 14, 1992, the FAA issued AD 92-22-01, Amendment 39-8387 
(58 FR 6191, January 27, 1993), to require rework or replacement of the 
existing ICC and replacement of the NL sensor port sealing tube and the 
external air tube connecting the P2.5/P3 switching valve to the rear 
inlet case.
    Since the issuance of that AD, the manufacturer has developed 
additional hardware that will further reduce the risk of internal oil 
fires in the ICC.
    A proposal to supersede AD 92-22-01 was published in the Federal 
Register on November 3, 1993 (58 FR 58669). That action proposed to 
retain the requirements for rework or replacement of the existing ICC 
and replacement of the NL sensor port sealing tube and the external air 
tube connecting the P2.5/P3 switching valve to the rear inlet case. 
That action also proposed to extend the compliance end date for rework 
or replacement of the December 31, 1995, based upon fleet utilization 
rates and parts availability. In addition, that action proposed to 
require installation of an airflow deflector bracket nozzle assembly, 
or modification of the No. 5 bearing pressure air system. Finally, that 
action proposed to require installation of a No. 5 bearing vent tube 
assembly.
    PWC has issued the following service bulletins (SB): SB No. 21112, 
dated February 13, 1992; SB No. 20914, Revision 3, dated October 15, 
1991; SB No. 21113, Revision 1, dated May 4, 1992; SB No. 21111, 
Revision 1, dated June 22, 1992; SB No. 21088, Revision 1, dated 
November 12, 1991; and SB No. 21097, dated November 8, 1991. These SB's 
describe procedures for replacing the NL sensor port sealing tube and 
the external air tube connecting the P2.5/P3 switching valve to the 
rear inlet case.
    In addition, PWC has issued the following SB's: SB No. 20957, 
Revision 5, dated August 10, 1992, and SB No. 20962, Revision 4, dated 
August 10, 1992, that describe procedures for reworking the existing 2 
hole internal air passage ICC to a 19 hole design.
    PWC has also issued the following SB's: SB No. 21065, Revision 4, 
dated February 1, 1993, that describes procedures for installing an 
airflow deflector bracket nozzle assembly; SB No. 21211, dated January 
28, 1993, that describes procedures for modifying the No. 5 bearing 
pressure air system; and SB No. 21053, Revision 2, dated December 9, 
1991, that describes procedures for installing a No. 5 bearing vent 
tube assembly.
    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. Transport Canada issued AD's No. CF-91-
26R1, CF-92-03R1, and CF-92-06, mandating the accomplishment of the 
above service bulletins. 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.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter offered no objection to the proposed rule.
    One commenter states that earlier revisions to the SB's listed in 
the proposed rule should be acceptable for compliance, as the revisions 
were minor and did not materially affect the AD's requirements. The FAA 
concurs. PWC has issued PW100 Service Information Letter (SIL) No. PW-
281 that lists those SB's and revision levels that constitute 
acceptable methods of compliance to the actions required by this AD. 
The FAA has added a note to paragraph (f) of the AD to provide further 
guidance to operators on those acceptable alternate methods of 
compliance.
    One commenter states that the economic analysis in the proposed 
rule significantly underestimated costs to operators, by not including 
the costs for premature engine removal, added inspections and parts 
replacement not required by the proposed rule but required by the 
applicable maintenance manuals, and for life limited parts not suitable 
for reinstallation. The FAA does not concur. While other costs may be 
involved, they represent costs that will be borne by the operators 
eventually anyway. The economic analysis examines only those costs 
directly related to the actions required by the proposed rule. Although 
the AD may result in a hot section inspection at a time earlier than 
the operator originally scheduled, the costs of that inspection are not 
directly related to the requirements of the AD, and therefore are not a 
result of the AD. In addition, those costs will vary significantly for 
each engine, and, may not be accurate if extrapolated to a fleet-wide 
estimate based on a small sampling.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change described 
previously. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    The FAA estimates that 85 engines installed on aircraft of U.S. 
registry will be affected by this AD, that it will take approximately 8 
work hours per engine to accomplish the required actions, and that the 
average labor rate is $55 per work hour. The manufacturer advises the 
FAA that required parts will be supplied at no cost to the operator. 
Based on these figures, the total cost impact of the AD on U.S. 
operators is estimated to be $37,400.
    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.
    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 DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 
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, Incorporation by 
reference, 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 removing amendment 39-8387 (58 FR 
6191, January 27, 1993) and by adding a new airworthiness directive, 
Amendment 39-8927, to read as follows:

94-11-11   Pratt & Whitney Canada: Amendment 39-8927.
Docket 93-ANE-47. Supersedes AD 92-22-01, Amendment 39-8387.

    Applicability: Pratt & Whitney Canada (PWC) PW118A, PW123, PW124B, 
PW125B, and PW126A turboprop engines installed on but not limited to 
Embraer EMB-120, DeHavilland Dash 8 Series 300, Aerospatiale ATR 72, 
Fokker 50, and British Aerospace ATP aircraft.
    Compliance: Required as indicated, unless accomplished previously.
    To prevent fire in the engine intercompressor case (ICC) and 
nacelle cavities, inflight engine shutdown, and aircraft damage, 
accomplish the following:
    (a) Replace the low pressure rotor speed (NL) sensor port sealing 
tube and the external air tube connecting the P2.5/P3 switching valve 
to the rear inlet case at the next engine shop visit, but not later 
than October 21, 1994, 120 days after the date of publication in the 
Federal Register as follows:
    (1) For PW118A engines, in accordance with PWC Service Bulletin 
(SB) No. 21112, dated February 13, 1992, and SB No. 20914, Revision 3, 
dated October 15, 1991.
    (2) For PW123 engines, in accordance with PWC SB No. 21113, 
Revision 1, dated May 4, 1992.
    (3) For PW124B engines, in accordance with PWC SB No. 21111, 
Revision 1, dated June 22, 1992.
    (4) For PW125B engines, in accordance with PWC SB No. 21088, 
Revision 1, dated November 12, 1991.
    (5) For PW126A engines, in accordance with PWC SB No. 21097, dated 
November 8, 1991.
    (b) Install an airflow deflector bracket nozzle assembly in 
accordance with PWC SB No. 21065, Revision 4, dated February 1, 1993, 
or modify the No. 5 bearing pressure air system in accordance with SB 
21211, dated January 28, 1993, at the next engine shop visit, but not 
later than December 31, 1995.
    (c) Install a No. 5 bearing vent tube assembly in accordance with 
PWC SB No. 21053, Revision 2, dated December 9, 1991, at the next 
engine shop visit, but not later than December 31, 1995.
    (d) For engines incorporating the modifications specified by any 
revision level of PWC SB No. 20237, rework the existing 2 hole internal 
air passage ICC to a 19 hole design, or replace the existing ICC, in 
accordance with PWC SB No. 20957, Revision 5, dated August 10, 1992, or 
PWC SB No. 20962, Revision 4, dated August 10, 1992, at the next engine 
shop visit, but not later than December 31, 1995.
    (e) For the purpose of this AD, an engine shop visit is defined as 
when any major module is separated.
    (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. 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 1: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Engine Certification Office.
    NOTE 2: PWC has issued PW100 Service Information Letter (SIL) 
No. PW-281 that lists those SB's and revision levels that constitute 
acceptable methods of compliance to the requirements of this AD.
    (g) Special flight permits may be issued in accordance with 14 CFR 
21.197 and 21.199 to operate the aircraft to a location where the 
requirements of this AD can be accomplished.
    (h) The replacement and modifications shall be done in accordance 
with the following service bulletins: 

------------------------------------------------------------------------
 Document No.       Pages         Revision                Date          
------------------------------------------------------------------------
PWC SB No.              1-12  2                 December 9, 1991.       
 21053R2.                                                               
    Total                                                               
     pages: 12.                                                         
PWC SB No.              1-14  1                 May 4, 1992.            
 21113R1.                                                               
    Total                                                               
     pages: 14.                                                         
PWC SB No.               1-6  Original          February 13, 1992.      
 21112.                                                                 
    Total                                                               
     pages: 6.                                                          
PWC SB No.              1-13  1                 June 22, 1992.          
 21111R1.                                                               
    Total                                                               
     pages: 13.                                                         
PWC SB No.              1-18  1                 November 12, 1991.      
 21088R1.                                                               
    Total                                                               
     pages: 18.                                                         
PWC SB No.              1-18  4                 February 1, 1993.       
 21065R4.                                                               
    Total                                                               
     pages: 18.                                                         
PWC SB No.              1-11  Original          November 8, 1991.       
 21097.                                                                 
    Total                                                               
     pages: 11.                                                         
PWC SB No.               1-8  5                 August 10, 1992.        
 20957R5.                                                               
    Total                                                               
     pages: 8.                                                          
PWC SB No.               1-4  4                 August 10, 1992.        
 20962R4.                                                               
    Total                                                               
     pages: 4.                                                          
PWC SB No.              1-13  3                 October 15, 1991.       
 20914R3.                                                               
    Total                                                               
     pages: 13.                                                         
PWC SB No.              1-44  Original          January 28, 1993.       
 21211.                                                                 
    Total                                                               
     pages: 44.                                                         
------------------------------------------------------------------------

    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, Technical 
Publications Department, 1000 Marie Victorin, Longueuil, Quebec J4G 
1A1. Copies may be inspected at the FAA, New England Region, Office of 
the Assistant Chief 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.
    (i) This amendment becomes effective on July 25, 1994.

    Issued in Burlington, Massachusetts, on May 26, 1994.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 94-15011 Filed 6-22-94; 8:45 am]
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