Transport Canada (TC), which is the airworthiness authority for Canada, recently notified us that an unsafe condition may exist on PWC PW206B engines that have incorporated PWC SB No. 28119, and PW206C, PW206E, PW207D, and PW207E turboshaft engines. Transport Canada advises that two reports of
irregular LCF counting were observed between engines on the same helicopter, during weekly recording of LCF data in the engine log books. PWC investigated and confirmed that irregular DCU LCF count recordings can occur, registering above and below the LCF count data of a paired reference engine. LCF cycle count data is used to track life- limited critical rotating parts. Pratt & Whitney Canada determined that cycle counting history by the DCU becomes corrupted if system electrical power is shut off before the completion of data transfer. Data transfer occurs after engine shutdown, as the compressor revolutions per minute (rpm) decelerates through 20% speed. Operatorsmust verify the DCU data each week as described in the maintenance manual. However, some operators have not been verifying this data. This condition causes potential for some life limited rotating parts to be close to or even beyond the currently approved published life limits.
Relevant Service Information
We have reviewed and approved the technical contents of PWC Alert Service Bulletin (ASB) No. PW200-72-A28252, Revision 2, dated March 11, 2004. That ASB describes procedures to compare the LCF counting data recorded by the DCU to the data recorded in the engine log books. We have also reviewed and approved the technical contents of PWC service bulletin (SB) No. PW200-72-28253, dated February 12, 2004, that describes procedures for validating proper DCU automatic LCF counting before an engine is installed. Transport Canada classified these SBs as mandatory and issued AD No. CF-2004-06, dated March 31, 2004, in order to ensure the airworthiness of these PWC engines in Canada.Bilateral Airworthiness Agreement
These PWC PW206B, PW206C, PW206E, PW207D, and PW207E turboshaft engines are manufactured in Canada and are 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 This AD
The unsafe condition described previously is likely to exist or develop on other PWC PW206B, PW206C, PW206E, PW207D, and PW207E turboshaft engines of the same type design. We are issuing this AD to prevent critical rotating parts from exceeding published life limits, which could result in uncontained engine failure and possible loss of the helicopter. This AD requires a Comparison Check and a Consistency Check of the automatic LCF counting data made by the engine DCU on installed engines, at the following:
For engines with impeller and or compressor turbine (CT) disks and or power turbine (PT) disks having fewer than 2,000 cycles life limit remaining on the effective date of the AD; within the next 50 engine flight hours or two months, whichever occurs first, after the effective date of this AD; and
For engines with impeller and or CT disks and or PT disks having from 2,000 to 5,000 cycles life limit remaining on the effective date of the AD; within the next 200 engine flight hours or three months, whichever occurs first, after the effective date of this AD; and;
For engines with impeller and or CT disks and or PT disks having more than 5,000 cycles life limit remaining on the effective date of the AD; within the next500 engine flight hours or four months, whichever occurs first, after the effective date of this AD.
This AD also requires validating proper DCU automatic LCF counting before an engine is installed. You must use the service information described previously to perform the actions required by this AD.
FAA's Determination of the Effective Date
Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Docket Management System (DMS)
We have implemented new procedures for maintaining AD dockets electronically. As of May 17, 2004, we posted new AD actions on the DMS and assigned a DMS docket number. We track each action and assign a corresponding Directorate identifier. The DMS docket No. is in the form "Docket No. FAA-200X-XXXXX." Each DMS docket also lists theDirectorate identifier ("Old Docket Number") as a cross-reference for searching purposes.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "AD Docket No. FAA-2004-18585; Directorate Identifier 2004-NE-28-AD" in the subject line of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify it.
We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of the DMS Web site, anyone can find and readthe comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://dms.dot.gov.
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 with you. You can 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 docket that contains the AD, any comments received, and any final disposition in person at the DMS Docket Offices between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will
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 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 prepareda summary of the costs to comply with this AD 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Under 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 U.S.C. 106(g), 40113, 44701.
39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive: