E8-14320. Airworthiness Directives; Pratt & Whitney Canada PW206A, PW206B, PW206B2, PW206C, PW206E, PW207C, PW207D, and PW207E Turboshaft Engines

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

PW206 and PW207 compressor turbine (CT) disc bore areas may experience impact damage resulting from bending or fracture of the CT disc retaining nut. Damage of the CT disc bore area can reduce LCF capabilities of the CT disc, resulting in disc fracture.

We are proposing this AD to prevent damage to the CT disc bore area, which could result in possible uncontained failure of the engine and damage to the helicopter.

DATES:

We must receive comments on this proposed AD by July 25, 2008.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-0001.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• Fax: [phone].

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone [phone]) is the same as the Mail address provided in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Ian Dargin, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2007-0219; Directorate Identifier 2007-NE-46-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD based on those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

Transport Canada, which is the aviation safety authority for Canada, has issued AD CF-2007-24R1, dated December 21, 2007, (referred to after this as “the MCAI”) to correct an unsafe condition for the specified products. The MCAI states:

PW206 and PW207 compressor turbine (CT) disc bore areas may experience impact damage resulting from bending or fracture of the CT disc retaining nut. Damage of the CT disc bore area can reduce LCF capabilities of the CT disc, resulting in disc fracture.

Under high centrifugal loads, the CT disk retaining nut castellations might bend outward, then contact and mark the CT disk internal bore. Worldwide, a total of 5 events of CT nut damage and associated damage to the CT disk bore have been reported. A total of 195 out of 402 engines in the U.S. fleet have been inspected, with two cases of CT nut damage and no findings of disk damage, to date. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

PWC has issued Alert Service Bulletin (ASB) PW200-72-A28280, Revision 4, dated August 28, 2007. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

This product has been approved by the aviation authority of Canada, and is approved for operation in the United States. Pursuant to our bilateral agreement with Canada, they have notified us of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all information provided by Canada and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design. This proposed AD would require (1) inspecting the CT disc bore area for damage and if any damage is noticed, replacing the CT disc before further flight; and (2) replacing the existing CT disc retaining nut and associated hardware.

Differences Between the Proposed AD and the MCAI

Although the MCAI allows use of future revisions of PWC ASB PW200-72-A28280, we require the use of Revision 4 of that ASB.

Although the MCAI has a March 21, 2008 compliance date, we have a December 21, 2008 compliance date, based on a review of the risk assessment and the fleet inspection results to date.

Costs of Compliance

We estimate that this proposed AD would affect 402 engines of U.S. registry. We also estimate that it would take 8 work-hours per product to comply with this proposed AD. The average labor rate is $80 per work-hour. Required parts would cost about $500 per product. We expect that 1 disk on the remaining 207 engines will be replaced, at an estimated cost of $20,000. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $478,280. Our cost estimate is exclusive of possible warranty coverage.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. “Subtitle VII: Aviation Programs,” describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in “Subtitle VII, Part A, Subpart III, Section 44701: General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We 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 this 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket.

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 FAA 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new AD:

Pratt & Whitney Canada: Docket No. FAA-2007-0219; Directorate Identifier 2007-NE-46-AD.

Comments Due Date

(a) We must receive comments by July 25, 2008.

Affected ADs

(b) None.

Applicability

(c) This airworthiness directive (AD) applies to Pratt & Whitney Canada (PWC) PW206A, PW206B, PW206B2, PW206C, PW206E, PW207C, PW207D, and PW207E turboshaft engines.

(d) These engines are installed on, but not limited to, MD Explorer, Agusta S.p.A. A109, A109E, A109S, Bell Helicopter Textron Canada Limited 427, Bell 429, and Eurocopter Deutschland GmbH EC135 P1, and EC135 P2 helicopters.

(e) For engines that have been converted from one model to another, see Effectivity paragraph 1.A. of PWC Alert Service Bulletin (ASB) PW200-72-A28280, Revision 4, dated August 28, 2007.

Reason

(f) Transport Canada AD CF-2007-24R1, dated December 21, 2007, states:

PW206 and PW207 compressor turbine (CT) disc bore areas may experience impact damage resulting from bending or fracture of the CT disc retaining nut. Damage of the CT disc bore area can reduce LCF capabilities of the CT disc, resulting in disc fracture.

We are issuing this AD to prevent damage to the CT disc bore area, which could result in possible uncontained failure of the engine and damage to the helicopter.

Actions and Compliance

(g) Unless already done, do the following actions:

(1) For engines that have never had a shop visit and have accumulated 4,000 CT cycles or more since new; or for engines that accumulated 2,700 CT cycles or more since last shop visit, last CT disc inspection, or incorporation of PWC SB PW200-72-28287; within 1,150 hours of engine operating time since April 28, 2006 (original issue date of Alert Service Bulletin (ASB) PW200-72-A28280), but not later than December 21, 2008, whichever occurs first, accomplish the following in accordance with PWC ASB PW200-72-A28280, Revision 4, dated August 28, 2007:

(i) Inspect the CT disc bore area for damage and if any damage is noticed, replace the CT disc before further flight.

(ii) Replace the existing CT disc retaining nut and associated hardware.

(2) For engines that have never had a shop visit and have accumulated less than 4,000 CT cycles since new, before the engine reaches 4,000 CT cycles or by December 21, 2008, whichever occurs later, accomplish the following in accordance with PWC ASB PW200-72-A28280, Revision 4, dated August 28, 2007:

(i) Inspect the CT disc bore area for damage and if any damage is noticed, replace the CT disc before further flight.

(ii) Replace the existing CT disc retaining nut and associated hardware.

(3) For engines that have accumulated fewer than 2,700 CT cycles since last shop visit, last CT disc inspection, or incorporation of PWC SB PW200-72-28287; before the engine reaches 2,700 CT cycles or by December 21, 2008, whichever occurs later, accomplish the following in accordance with PWC ASB PW200-72-A28280, Revision 4, dated August 28, 2007:

(i) Inspect the CT disc bore area for damage and if any damage is noticed, replace the CT disc before further flight.

(ii) Replace the existing CT disc retaining nut and associated hardware.

Previous Credit

(h) Inspection of the CT disc bore and replacement of the CT disc retaining nut using PWC ASB PW200-72-A28280, dated April 28, 2006, or Revision 1, dated May 11, 2006, or Revision 2, dated September 29, 2006, or Revision 3, dated December 11, 2006, before the effective date of this AD, meet the requirements of this AD.

(i) Alternative Methods of Compliance (AMOCs): The Manager, Engine Certification Office, FAA, may approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

Related Information

(j) Refer to Transport Canada Airworthiness Directive 2007-24R1, dated December 21, 2007, for related information.

(k) Contact Ian Dargin, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park; Burlington, MA 01803; e-mail: [e-mail]; telephone [phone]; fax [phone].

Issued in Burlington, Massachusetts, on June 19, 2008.

Diane Cook,

Acting Manager, Engine and Propeller Directorate, Aircraft Certification Service.