AD/JT15D/10 Engine P3 Compressor Delivery Tube (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 - JT15D Series

AD/JT15D/10 Engine P3 Compressor Delivery Tube 9/2008

Applicability:

Pratt & Whitney Canada (P&WC):

JT15D-5 engines which are before and include serial number PCE-100411; and

JT15D-5 engines which are before and include serial number PCE-JA0818; and

All JT15D-5B engines; and

All JT15D-5F engines; and

JT15D-5R engines which are before and include serial number PCE-JG0104; and

All JT15D-5 engines converted to model JT15D-5R by incorporation of P&WC Service Bulletin (SB) 7605.

Requirement:

Unless previously accomplished, incorporate P&WC Alert Service Bulletin (ASB) number A7611 Revision No. 1 dated 16 June 2008, or later revisions approved by Transport Canada.

Compliance with P&WC ASB A7611 dated 26 March 2008 prior to the effective date of this directive satisfies the corrective actions requirement of this directive.

Note:  Transport Canada AD CF-2008-23 dated 27 June 2008 refers.

Compliance:

Within 200 flight hours after the effective date of this directive, or before
31 December 2008, whichever occurs first.

This Airworthiness Directive becomes effective on 28 August 2008.

Background:

There have been several reported incidents of high altitude, dual engine flameout on JT15D-5 engines powered aircraft operating in certain meteorological conditions. Subsequent to the investigation of incidents, review of the engine design has revealed that the Fuel Control Hydro Mechanical Unit (HMU) P3 servo can be exposed to excessive moisture and freezing.  To preclude P3 servo freezing, P&WC has issued JT15D ASB A7611 to re-route compressor delivery air to the HMU and improve moisture separation.

Considering the potentially hazardous consequence of possible in-flight dual engine flameout, this AD is issued to mandate the incorporation of P&WC ASB A7611 to the affected JT15D-5 engines, in order to minimize the possibility of this hazard.

James Coyne
Delegate of the Civil Aviation Safety Authority

16 July 2008