[Federal Register Volume 69, Number 34 (Friday, February 20, 2004)]
[Proposed Rules]
[Pages 7878-7881]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-3682]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 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.
 
 ========================================================================
 

  Federal Register / Vol. 69, No. 34 / Friday, February 20, 2004 / 
Proposed Rules  

[[Page 7878]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NE-25-AD]
RIN 2120-AA64


Airworthiness Directives; Pratt & Whitney Canada PW206A and 
PW206E Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) for Pratt & Whitney Canada (PWC) PW206A and PW206E 
turboshaft engines. That AD currently requires initial and repetitive 
borescope inspections of compressor turbine and power turbine blades 
for blade axial shift, and replacement of blade retaining rivets and 
certain rotor air seals as terminating action for the repetitive 
borescope inspections.
    This proposed AD would require the same actions but needs to 
clarify the extent of engine disassembly that triggers the required 
part replacements. This proposed AD is prompted by reports of engine 
shutdowns and emergency landings due to severe vibration, resulting in 
exhaust gases escaping from the engine-to-exhaust nozzle interface, 
thereby triggering in-flight engine fire warnings. We are proposing 
this AD to prevent turbine blade axial shift, which could cause high 
levels of vibration, loss of engine torque, in-flight engine shutdown, 
and loss of the airframe exhaust duct.

DATES: We must receive any comments on this proposed AD by April 20, 
2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD:
     By mail: Federal Aviation Administration (FAA), 
New England Region, Office of the Regional Counsel, Attention: Rules 
Docket No. 2003-NE-25-AD, 12 New England Executive Park, Burlington, MA 
01803-5299.
     By fax: (781) 238-7055.
     By e-mail: [email protected]
    You can get the service information identified in this proposed AD 
from Pratt & Whitney Canada, 1000 Marie-Victorin, Longueuil, Quebec, 
Canada J4G1A1.
    You may examine the AD docket, by appointment, at the FAA, New 
England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Ian Dargin, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-
7178; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``AD Docket No. 2003-NE-25-AD'' in the 
subject line of your comments. If you want us to acknowledge receipt of 
your mailed comments, send us a self-addressed, stamped postcard with 
the docket number written on it; we will date-stamp your postcard and 
mail it back to you. We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of the proposed 
AD. If a person contacts us through a nonwritten communication, and 
that contact relates to a substantive part of this proposed AD, we will 
summarize the contact and place the summary in the docket. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications that affect you. You may get more information about 
plain language at http://www.faa.gov/language and http://www.plainlanguage.gov.

Examining the AD Docket

    You may examine the AD Docket (including any comments and service 
information), by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. See ADDRESSES for the 
location.

Discussion

    On August 4, 2003, the FAA issued airworthiness directive (AD) 
2003-16-10, Amendment 39-13263 (68 FR 48544, August 14, 2003), to 
require initial and repetitive borescope inspections of compressor 
turbine and power turbine blades for blade axial shift. That AD also 
required replacement of blade retaining rivets and certain rotor air 
seals as terminating action for the repetitive borescope inspections. 
That action was prompted by reports of engine shutdowns and emergency 
landings due to severe vibration and drops in engine torque, and an 
increase in internal engine temperature, triggering in-flight engine 
fire warnings. That condition, if not corrected, could result in 
turbine blade axial shift, which could cause high levels of vibration, 
loss of engine torque, in-flight engine shutdown, and loss of the 
airframe exhaust duct.

Comments Received Since AD 2003-16-10 Was Issued

    Since that final rule; request for comments was issued, we received 
two comments on that AD. We have considered those comments.

Request To Clarify the Extent of Engine Disassembly Required

    One commenter requests clarification in the AD of the extent of 
engine disassembly that would trigger the part replacements and 
clarification of the rework specified in the terminating action. The 
commenter states that more extensive disassembly is required to do the 
part replacement specified in Part B of PWC SB No. 200-72-28069, 
Revision 5, dated February 10, 2003, than to do the part rework 
specified in Part A of that SB. The commenter also states that the 
triggering event of a shop visit for any reason is too restrictive.
    The FAA agrees. We have rewritten the terminating action to be done 
at the next engine shop visit when access is available to subassembies, 
such as modules, accessories, and components, or at the next engine 
overhaul,

[[Page 7879]]

whichever occurs first, but before accumulating 1,800 flight hours from 
the effective date of this AD or before December 31, 2009, whichever 
occurs first.

Request To Clarify the Preamble

    One commenter requests clarification of what prompted the AD. The 
commenter suggests that the words describing the actions prompting this 
AD be changed to state that the AD is being issued to prevent turbine 
blade axial shift, leading to high levels of vibration and possible in-
flight engine shutdown.
    The FAA agrees to the suggested changes to the preamble, which have 
been incorporated into this document. There have been six emergency 
landings due to high vibration levels and in-flight engine fire 
warnings, one incident of the loss of the airframe exhaust duct, one 
in-flight shutdown, one pilot report of high oil consumption, and one 
pilot report of loss of torque. To date, there have been no failures 
that have resulted in uncontained engine failures. The aircraft warning 
and detection system should preclude uncontained engine failures from 
occurring. We agree that the loss of the airframe exhaust duct should 
have been referenced in the preamble to the current AD. Therefore, the 
preamble of this proposal is written to reference the loss of the 
airframe exhaust duct.

Correction To Include No. 4 Bearing Rear Rotor Air Seal

    The reference to replacing the No. 4 bearing rear rotor air seal 
was inadvertently omitted from the compliance section of the AD. We 
have rewritten paragraph (i) of the AD to include replacing of the No. 
4 bearing rear rotor air seal.

Relevant Service Information

    We have reviewed and approved the technical contents of the 
following Pratt & Whitney Canada service documents:
     Alert Service Bulletin (ASB) No. PW200-72-
A28242, Revision 1, dated October 2, 2002, that describes procedures 
for borescope inspecting of compressor turbine blades and power turbine 
blades for axial shift within the disks.
     Service Bulletin (SB) No. PW200-72-28069, 
Revision 5, dated February 10, 2003, that describes procedures for 
replacing compressor turbine blade retaining rivets, the No. 3 bearing 
rotor air seal, and the No. 4 bearing front rotor air seal.
     SB No. PW200-72-28239, Revision 2, dated 
February 10, 2003, that describes procedures for replacing power 
turbine blade retaining rivets. Transport Canada, which is the 
airworthiness authority for Canada, classified these service bulletins 
as mandatory and issued AD CF-2003-06, dated February 4, 2003, in order 
to ensure the airworthiness of these PWC PW206A and PW206E turboshaft 
engines in Canada.

Bilateral Agreement Information

    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. Under this bilateral 
airworthiness agreement, Transport Canada has kept the FAA informed of 
the situation described above. We have 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.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. Therefore, we are proposing this AD, which 
would require:
     Initial and repetitive borescope inspections of 
compressor turbine blades and power turbine blades for blade axial 
shift within the turbine disks; and
     Replacement of blade retaining rivets, the No. 3 
bearing rotor air seal, and the No. 4 bearing front rotor air seal as 
mandatory terminating action for the repetitive borescope inspections.
    You must use the service information described previously to 
perform the actions required by this AD.

Changes to 14 CFR Part 39--Effect on the Proposed AD

    On July 10, 2002, we issued a new version of 14 CFR part 39 (67 FR 
47998, July 22, 2002), which governs the FAA's AD system. This 
regulation now includes material that relates to altered products, 
special flight permits, and alternative methods of compliance. This 
material previously was included in each individual AD. Since this 
material is included in 14 CFR part 39, we will not include it in 
future AD actions.

Costs of Compliance

    There are about 130 PWC PW206A and PW206E turboshaft engines of the 
affected design in the worldwide fleet. We estimate that 15 engines 
installed on airplanes of U.S. registry would be affected by this 
proposed AD. We also estimate that it would take about 0.5 work hours 
per engine to perform the proposed actions, and that the average labor 
rate is $65 per work hour. Required parts would cost about $9,077 per 
engine. Based on these figures, we estimate the total cost of the 
proposed AD to U.S. operators to be $136,656. The manufacturer has 
stated that it may provide replacement parts at no cost to operators.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD 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.
    For the reasons discussed above, I certify that the 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. Would not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.
    We prepared a summary of the costs to comply with this proposal and 
placed it in the AD Docket. You may get a copy of this summary by 
sending a request to us at the address listed under ADDRESSES. Include 
``AD Docket No. 2003-NE-25-AD'' in your request.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 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. The FAA amends Sec.  39.13 by removing Amendment 39-13263 (68 FR 
48544, August 14, 2003) and by adding a new airworthiness directive, to 
read as follows:


[[Page 7880]]


Pratt & Whitney Canada: Docket No. 2003-NE-25-AD. Supersedes AD 
2003-16-10, Amendment 39-13263.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by April 20, 
2004.

Affected ADs

    (b) This AD supersedes AD 2003-16-10, Amendment 39-13263.

Applicability

    (c) This AD applies to Pratt & Whitney Canada (PWC) PW206A and 
PW206E turboshaft engines. These PWC engines are installed on, but 
not limited to, MD Helicopters Inc. Model MD-900 helicopters.

Unsafe Condition

    (d) This AD is prompted by the need to clarify the extent of 
engine disassembly that triggers the required part replacements. 
This AD is also prompted by reports of engine shutdowns and 
emergency landings due to severe vibration, resulting in exhaust 
gases escaping from the engine-to-exhaust nozzle interface, thereby 
triggering in-flight engine fire warnings. The actions specified in 
this AD are intended to prevent turbine blade axial shift, leading 
to high levels of vibration, in-flight engine shutdowns and loss of 
the airframe exhaust duct.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified unless the 
actions have already been done.

Initial Sequence of Borescope Inspections

    (f) Perform an initial sequence of borescope inspections of 
compressor turbine blades and power turbine blades for blade axial 
shift within the turbine disks. Use paragraph 3. of Accomplishment 
Instructions of PWC Alert Service Bulletin (ASB) No. PW200-72-
A28242, Revision 1, dated October 2, 2002, for the borescope 
inspection and determination of blade shift. Do the inspections at 
the following times:
    (1) Within 25 flight hours accumulated, or 30 days after the 
effective date of this AD, whichever occurs earlier.
    (2) After 30 flight hours, but before 50 flight hours 
accumulated since inspection of paragraph (f)(1) of this AD.
    (3) After 80 flight hours, but before 100 flight hours 
accumulated since inspection of paragraph (f)(1) of this AD.
    (4) After 180 flight hours, but before 200 flight hours 
accumulated since inspection of paragraph (f)(1) of this AD.

Repetitive Borescope Inspections

    (g) Thereafter, perform repetitive borescope inspections at 
intervals of not less than 280 nor more than 300 flight hours since-
last-inspection. Use paragraph 3. of Accomplishment Instructions of 
PWC ASB No. PW200-72-A28242, Revision 1, dated October 2, 2002, for 
the borescope inspections and determination of blade shift.

Disposition

    (h) If you find any blade shift, remove engine from service 
before further flight and perform rivet and rotor air seal 
replacements, as specified in paragraphs (i)(1) through (i)(3) of 
this AD, to return the engine to service.

Terminating Action

    (i) At the next engine shop visit when access is available to 
subassembies, such as modules, accessories, and components, or at 
the next engine overhaul, whichever occurs first, but before 
accumulating 1,800 flight hours from the effective date of this AD 
or before December 31, 2009, whichever occurs first, do the 
following:
    (1) Replace the compressor turbine blade retaining rivets with 
new P/N retaining rivets, and the No. 4 bearing rear rotor air seal 
with the new P/N No. 4 bearing rear rotor air seal. Use paragraph 
3., Part A, of Accomplishment Instructions of SB No. PW200-72-28069, 
Revision 5, dated February 10, 2003.
    (2) Replace the No. 3 bearing rotating air seal with the new P/N 
air seal, and the No. 4 bearing front rotor air seal with the new P/
N No. 4 bearing front rotor air seal. Use paragraph 3., Part B, of 
Accomplishment Instructions of SB No. PW200-72-28069, Revision 5, 
dated February 10, 2003.
    (3) Replace the power turbine blade retaining rivets with new P/
N power turbine blade retaining rivets. Use paragraph 3. of 
Accomplishment Instructions of SB No. PW200-72-28239, Revision 2, 
dated February 10, 2003.
    (j) Completing the actions in paragraphs (i)(1) through (i)(3) 
of this AD terminate all inspection requirements of this AD.

Previous Credit

    (k) Previous credit is allowed:
    (1) For performing the initial sequence for borescope 
inspections in paragraph (f) of this AD, that were done using AD 
2003-16-10.
    (2) For terminating action in paragraphs (i)(1) through (i)(3) 
of this AD that was done using Accomplishment Instructions of SB No. 
PW200-72-28069, Revision 4, dated December 27, 2000, and 
Accomplishment Instructions of SB No. PW200-72-28239, dated 
September 5, 2002, or Revision 1, dated December 5, 2002, before the 
effective date of this AD.

Alternative Methods of Compliance

    (l) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD if 
requested using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

    (m) You must use the following Pratt & Whitney Canada Service 
Bulletins and Alert Service Bulletin to perform the inspections and 
replacement actions required by this AD. The Director of the Federal 
Register approved the incorporation by reference of the documents 
listed in Table 1 of this AD as of August 29, 2003 (68 FR 48544, 
August 14, 2003), in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. You may get a copy from Pratt & Whitney Canada, 1000 Marie-
Victorin, Longueuil, Quebec, Canada J4G1A1. You may review copies at 
Federal Aviation Administration (FAA), New England Region, Office of 
the Regional Counsel, Attention: Rules Docket No. 2003-NE-25-AD, 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. Table 1 follows:

                                      Table 1.--Incorporation by Reference
----------------------------------------------------------------------------------------------------------------
           Service bulletin                 Page number(s)         Revision                  Date
----------------------------------------------------------------------------------------------------------------
PW200-72-A28242......................  All.....................            1  October 2, 2002.
Total Pages--7.
PW200-72-28069.......................  All.....................            5  February 10, 2003.
Total Pages--17.
PW200-72-28239.......................  All.....................            2  February 10, 2003.
Total Pages--20.
----------------------------------------------------------------------------------------------------------------


[[Page 7881]]

Related Information

    (n) Transport Canada issued airworthiness directive CF-2003-06, 
dated February 4, 2003, which pertains to the subject of this AD, in 
order to assure the airworthiness of these PWC PW206A and PW206E 
turboshaft engines in Canada.

    Issued in Burlington, Massachusetts, on February 13, 2004.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 04-3682 Filed 2-19-04; 8:45 am]
BILLING CODE 4910-13-P