[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:
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Document No. Pages Revision Date
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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.
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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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