[Federal Register Volume 62, Number 39 (Thursday, February 27, 1997)]
[Rules and Regulations]
[Pages 9068-9070]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-4993]



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Part IV





Department of Transportation





_______________________________________________________________________



Federal Aviation Administration



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14 CFR Part 39



Airworthiness Directives; Pratt & Whitney Canada PT6 Series Turboprop 
Engines; Final Rule

  Federal Register / Vol. 62, No. 39 / Thursday, February 27, 1997 / 
Rules and Regulations  

[[Page 9068]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-01; Amendment 39-9936; AD 97-04-12]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Canada PT6 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 certain Pratt & Whitney Canada (PWC) PT6 series 
turboprop engines. This action requires a one-time visual inspection of 
compressor bleed-off valves (BOVs) to determine if an affected 
supplier's code number is on the cover; and, if so, this AD requires 
the removal of the bleed valve cover assembly from the compressor bleed 
valve housing assembly and inspection of the cotter pin and the guide 
shaft pin. If the cotter pin or guide shaft pin is not acceptable, this 
AD requires modifying the compressor BOV or replacing it with a 
serviceable part. This amendment is prompted by reports of two 
malfunctions of compressor BOVs that resulted in inflight engine power 
reduction. The actions specified in this AD are intended to prevent 
engine power reduction due to malfunction of the compressor BOV, which 
could result in a forced landing and loss of the aircraft.

DATES: Effective March 14, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 14, 1997.
    Comments for inclusion in the Rules Docket must be received on or 
before April 28, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 97-ANE-01, 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; telephone (514) 677-9411, fax (514) 647-3620. This information 
may be examined 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.

FOR FURTHER INFORMATION CONTACT: Diane Cook, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone (617) 238-
7134, fax (617) 238-7199.

SUPPLEMENTARY INFORMATION: Transport Canada, which is the airworthiness 
authority for Canada, recently notified the FAA that an unsafe 
condition may exist on certain Pratt & Whitney Canada (PWC) PT6 series 
turboprop engines installed on single engine aircraft. Transport Canada 
advises that it has received reports of two malfunctions of compressor 
bleed-off valves (BOVs) on PWC PT6A-25C series engines, resulting in 
inflight engine power reduction. The investigation revealed that the 
cause of the compressor BOV malfunction was broken cotter pins. The 
debris from the cotter pins interfered with the movement of the BOV 
piston, which resulted in the BOV remaining in the closed position. The 
cotter pins broke due to stress loading from the guide shaft pin, which 
was improperly installed and loose. Further investigation indicates the 
compressor BOVs from the two malfunctions are from the same supplier. 
All BOVs produced from this supplier, which is approximately 1,000 
compressor BOVs since January 1995, are the suspect population. The 
compressor BOVs are common to all PWC PT6 series engine models. This 
condition, if not corrected, could result in engine power reduction due 
to malfunction of the compressor BOV, which could result in a forced 
landing and loss of the aircraft.
    Pratt & Whitney Canada has issued the following Service Bulletins 
(SBs): 14251, Revision 1, dated December 2, 1996; 13287, Revision, 
dated December 2, 1996; 12134, Revision 1, dated December, 1996; 4204, 
dated December 10, 1996, Original; 3344, Revision 1, dated December 3, 
1996; and 1538, Revision 3, dated December 2, 1996. The SBs describe 
procedures for visually inspecting BOVs to determine if the affected 
supplier's code number (No.) is on the cover. If the code No. is 
present, the SB describes the procedures for the removal of the bleed 
valve cover assembly from the bleed valve housing assembly, the 
inspection of the cotter pin and the guide shaft pin, the installation 
of a new compressor valve cover assembly if necessary, the reassembly 
of the bleed valve cover assembly to the bleed valve assembly, and the 
reidentification of the bleed valve assembly. Transport Canada 
classified these SBs as mandatory and issued Emergency AD CF-96-24, 
which is applicable to all PT6A engines installed in single engine 
aircraft, in order to assure the airworthiness of these 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 (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.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design registered in 
the United States, the proposed AD would require, within 100 hours time 
in service after the effective date of this AD, but no later than April 
2, 1997, a one-time visual inspection of compressor BOVs to determine 
if the affected supplier's code No. 8070, is on the cover. No further 
action is required if code No. 8070 is not on the cover, or if the 
compressor BOV has been marked with the reidentification ``RE71'' 
adjacent to the part number. If code No. 8070 is found and the 
compressor BOV has not been marked for reidentification, this AD 
requires inspecting the cotter pin for any wear indications and the 
guide shaft pin for any movement described in the applicable SB. If the 
cotter pin or guide shaft pin is not acceptable, this AD requires, 
prior to further flight, modifying the compressor BOV or replacing it 
with a serviceable part. If the conditions of the cotter pin and the 
guide shaft pin are acceptable, this AD requires the replacement of the 
cotter pin, and the reidentification of the bleed valve assembly in 
accordance with the PW SB. The calendar end-date of April 2, 1997, was 
determined based upon safety considerations and parts availability. The 
actions would be required to be accomplished in accordance with the SBs 
described previously.
    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

[[Page 9069]]

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 97-ANE-01.'' 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, Incorporation by 
reference, Safety.

Adoption of the 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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:
97-04-12  Pratt & Whitney Canada: Amendment 39-9936. Docket 97-ANE-
01.

    Applicability: Pratt & Whitney Canada (PWC) PT6 series turboprop 
engines manufactured after January 1, 1995, or any PT6 series 
engines that have had their compressor bleed-off valve (BOV) changed 
after January 1, 1995, and which are installed in single-engine 
aircraft including, but not limited to the following aircraft: Air 
Tractor AT, Ayres Turbo Thrush Commander, Cessna 208 Caravan, Argo 
Aircraft G169B, Embraer EMB-312 Tucano, Frakes AF-CAT, Pilatus PC-6, 
PC-7, PC-9, and PC-12, Schweitzer AG-CAT, Aerospatiale Socata TBM-
700, and Raytheon (Beech) T-34C.

    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 (e) 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 engine power reduction due to malfunction of the 
compressor BOV, which could result in a forced landing and loss of 
the aircraft, accomplish the following:
    (a) Within 100 hours time in service (TIS) after the effective 
date of this AD, but no later than April 2, 1997, perform a visual 
inspection of compressor BOVs to determine if the affected 
supplier's code number (No.) 8070, is on the cover, in accordance 
with the following PWC Service Bulletins (SBs), as applicable: 
14251, Revision 1, dated December 2, 1996; 13287, Revision 1, dated 
December 2, 1996; 12134, Revision 1, dated December 2, 1996; 4204, 
dated December 10, 1996, Original; 3344, Revision 1, dated December 
3, 1996; and 1538, Revision 3, dated December 2, 1996.
    (b) No further action is required if code No. 8070 is not on the 
cover of the compressor BOV, or if the compressor BOV has been 
marked with the reidentification ``RE71'' adjacent to the part 
number.
    (c) For compressor BOVs with code No. 8070 and no 
reidentification ``RE71'' marking, prior to further flight remove 
and inspect the cotter pin for any wear indications and inspect the 
guide shaft pin for any movement in accordance with the applicable 
SB listed in paragraph (a) of this AD.
    (1) If the cotter pin or guide shaft pin is not acceptable in 
accordance with the applicable SB listed in paragraph (a) of this 
AD, prior to further flight, modify the compressor BOV in accordance 
with the applicable SB listed in paragraph (a) of this AD, or 
replace it with a serviceable part.
    (2) If the cotter pin and the guide shaft pin are acceptable in 
accordance with the applicable SB listed in paragraph (a) of this 
AD, prior to further flight, replace the cotter pin with a 
serviceable part.
    (d) Assemble and install the compressor bleed valve cover 
assembly on the housing assembly and reidentify the bleed valve 
assembly with ``RE71'' in accordance with the applicable SB listed 
in paragraph (a) of this AD.
    (e) 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, Certification Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (f) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the aircraft to a location where 
the requirements of this AD can be accomplished.
    (g) The actions required by this AD shall be accomplished in 
accordance with the following PWC SBs:

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              Document No.                Pages           Revision                          Date                
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14251..................................      1-9  1......................  December 2, 1996.                    
      Total pages: 9...................                                                                         
13287..................................     1-11  1......................  December 2, 1996.                    
      Total pages: 11..................                                                                         
12134..................................      1-8  1......................  December 2, 1996.                    
      Total pages: 8...................                                                                         
4204...................................     1-11  Original...............  December 10, 1996.                   
      Total pages: 11..................                                                                         
3344...................................     1-11  1......................  December 3, 1996.                    
      Total pages: 11..................                                                                         
1538...................................      1-9  3......................  December 2, 1996.                    
      Total pages: 9...................                                                                         
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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, 1000 
Marie-Victorin, Longueuil, Quebec, Canada J4G 1A1; telephone (514) 
677-9411, fax (514) 647-3620. 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.
    (h) This amendment becomes effective on March 14, 1997.

    Issued in Burlington, Massachusetts, on February 18, 1997.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 97-4993 Filed 2-26-97; 9:21 am]
BILLING CODE 4910-13-U