AD/PW500/3 Hydro-mechanical Fuel Control Units (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Pratt and Whitney Canada Turbine Engines - PW500 Series

AD/PW500/3 Hydro-mechanical Fuel Control Units 14/2010

Applicability:

Pratt & Whitney Canada PW535A engines prior to serial number DC0241 with hydro-mechanical fuel control (HFC) P/N 819735-4, 819735-5, or 819735-6.

Requirement:

Unless previously accomplished, action in accordance with the requirements of Transport Canada AD CF-2004-28.

Note:  P&WC ASB A30257R1 and P&WC Engine Maintenance Manual 3044952 R14 refer.

Compliance:

For installed HFC units, within 50 hours after the effective date of this AD.

For HFC units not installed, at time of installation.

This Airworthiness Directive becomes effective on 16 July 2010.

Background:

Incidents of PW535A engines experiencing lack of response to the power lever input due to an incorrect adjustment of the HFC ratio unit setscrew during engine acceleration time setting has been reported.  As a result, this AD requires inspection and verification of the proper adjustment of the HFC ratio unit setscrew, and implementation of correct installation procedures.

David Punshon
Delegate of the Civil Aviation Safety Authority

5 July 2010