Airworthiness Directive · Amendment 39-22001 · Engine oil cooler
Pratt & Whitney Division Turbofan Engines
This AD applies to Pratt & Whitney Division PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 model turbofan engines, with an installed air/oil heat exchanger that has accumulated any number of cycles since new (CSN) or cycles since last overhaul.
The FAA is adopting a new airworthiness directive (AD) for all Pratt & Whitney Division (PW) PW4074, PW4074D, PW4077, PW4077D, PW4084D, PW4090, and PW4090-3 model turbofan engines. This AD was prompted by an in-flight shutdown (IFSD) of an engine due to an air/oil heat exchanger leak caused by corrosion and subsequent investigation by the manufacturer that revealed additional air/oil heat exchanger leaks. This AD requires an inspection of the air/oil heat exchanger and, depending on the results of the inspection, replacement of the air/oil heat exchanger. This AD also provides instructions for storing an air/ oil heat exchanger after inspection. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within 30 days prior to the first flight after the effective date of this AD, perform an inspection for leaks of the air/oil heat exchanger in accordance with the Accomplishment Instructions, paragraph 3., of Pratt & Whitney Special Instruction No. 255F-21A, dated February 15, 2022.
(2) If any air/oil heat exchanger fails the inspection required by paragraph (g)(1) of this AD, before further flight, remove the air/oil heat exchanger and replace with a part eligible for installation.
For the purpose of this AD, a “part eligible for installation” is:
(1) A new air/oil heat exchanger with zero CSN, or
(2) An overhauled air/oil heat exchanger with zero cycles since last overhaul, or
(3) An air/oil heat exchanger that has passed the inspection required by paragraph (g)(1) of this AD.
For performance of the inspection for leaks required by paragraph (g)(1) of this AD, the air/oil heat exchanger may be inspected more than 30 days prior to the first flight after the effective date of this AD if, after performing said inspection, the following are accomplished:
(1) The air/oil heat exchanger is stored in accordance with the Accomplishment Instructions, paragraph 6., of Pratt & Whitney Special Instruction No. 255F-21A, dated February 15, 2022; and
(2) The cumulative time between performance of the inspection and the first flight minus the time stored in accordance with paragraph (i)(1) of this AD does not exceed 30 days.
