Summary
We propose to adopt a new airworthiness directive (AD) for certain Pratt & Whitney Division (PW) PW2037, PW2037M, and PW2040 turbofan engines. This proposed AD was prompted by an unrecoverable engine in-flight shutdown (IFSD) after an ice crystal icing event. This proposed AD would require installing a software standard eligible for installation and preclude the use of electronic engine control (EEC) software standards earlier than SCN 5B/I. We are proposing this AD to correct the unsafe condition on these products.