AD/PT6A/32 - Exhaust Duct Cracking (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 39.1 (1) of CAR 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 - PT6A Series

AD/PT6A/32 Exhaust Duct Cracking 3/2003

Applicability: All PT6A-6, -6A, -6B, -11, -11AG, -15AG, -20, -20A, -20B, -21, -25, -25A, -25C, - 27, -28, -34, -34AG, -34B, -36, -110, -112, -135, and –135A series turboprop engines fitted with turbine exhaust ducts that are not in compliance with Pratt and Whitney Canada (P&WC) Service Bulletins (SB) 1610, 1610R1, 1610R2 or 12173R1.

Requirement: 1. Inspect the turbine exhaust duct for low-quality welds, created during repair, on the turbine exhaust duct near flange "A", in accordance with Paragraphs 3B through 3E of:

1. P&WC SB PT6A-72-1610 Revision 2 for models PT6A-6, -6A, -6B, -20, - 20A, -20B, -21, -25, -25A, -25C, -27, -28, -34, -34AG, -34B, -36, -135, and - 135A engines; or

b. P&WC SB PT6A-72-12173 Revision 1 for models PT6A-11, -11AG, - 15AG, -110, and -112 engines.

2. If it is determined that the welds meet acceptable criteria as detailed in Requirement 1a or 1b of this Directive:

1. Return the duct to service.