Document ID: chunk:federal_register_of_legislation:F2006B06389:body:0:p2
Version: federal_register_of_legislation:F2006B06389
Segment Type: other
Provision Reference: 
Character Range: 2829–6049

28253, dated 12 February 2004.

            Compliance with previous revisions of P&WC ASB A28252 prior to the effective date of this Directive satisfies the requirements of ASB A28252, Revision 2, mandated by Requirements 1, 2 and 3 of this Directive.

4.         Incorporate the following P&WC Temporary Revisions (TR) into the Airworthiness Limitation Section of the applicable engine Maintenance Manuals:

 Engine Model      Maintenance Manual Part Number  TR Number     TR Date
PW206B               3039732                       AL-10, AL-11  11 March 2004
PW206C               3043322                       AL-8, AL -9   11 March 2004
PW206E               3038324                       AL-15, AL-16  11 March 2004
PW207D               3043612                           AL-5      11 March 2004
PW207E               3038324                       AL-15, AL-16  11 March 2004

            Note 2: Transport Canada AD CF-2004-06 refers.

 Compliance: For Requirement 1 - Compliance as follows:

                For engines with Impeller and/or Compressor Turbine (CT) Disks and/or Power Turbine (PT) Disks having less than 2,000 cycles life limit remaining - Within the next 50 engine flight hours or 2 months, whichever occurs first after the effective date of this Directive.

                For engines with Impeller and/or CT Disks and/or PT Disks having from 2,000 to 5,000 cycles life limit remaining - Within the next 200 engine flight hours or 3 months, whichever occurs first after the effective date of this Directive.

                For engines with Impeller and/or CT Disks and/or PT Disks having more than 5,000 cycles life limit remaining - Within the next 500 engine flight hours or 4 months, whichever occurs first after the effective date of this Directive.

            For Requirement 2 - Before further flight after the Requirement 2 checks. For Requirement 3 - Before the engines are installed in helicopters.
            For Requirement 4 - Before 30 July 2004.

            This Airworthiness Directive becomes effective on 14 July 2004.

            Background: Transport Canada has advised that two cases were identified where the PW206 DCU had not adequately recorded the engine LCF cycles, which are used to track life limited critical parts. Operators are required to verify the DCU data each week in accordance with the maintenance manual. However, it appears some operators were not confirming/verifying this data.

            This problem is caused when the electrical supply to the Engine Electronic Control (EEC) or DCU is turned OFF prematurely during engine shutdown.

            There is a potential for some life-limited parts to be close to or even beyond the currently approved and published limits. Hence, this Directive requires operators to verify their engine log books to confirm the LCF count.

            Pratt & Whitney Canada has requested relevant helicopter manufacturers to amend their Aircraft Flight Manuals to prevent DCU corruption and errors by ensuring that the EEC remains powered until Ng (N1) speed reaches zero.

 Bernard Malcolm Hole
 Delegate of the Civil Aviation Safety Authority 5 July 2004

 The above AD is notified in