Airworthiness Directives; Pratt & Whitney Division Turbofan

We are superseding Airworthiness Directive (AD) 2017-12-03 for certain Pratt & Whitney Division (PW) PW2037, PW2037M, and PW2040 turbofan engines. AD 2017-12-03 required installing a software standard eligible for installation and precludes the use of electronic engine control (EEC) software standards earlier than SCN 5B/I. This AD requires installing a software standard eligible for installation and preclude the use of EEC software standards earlier than SCN 5B/I or SCN 27A. This AD was prompted by an unrecoverable engine in-flight shutdown (IFSD) after an ice crystal icing event. We are issuing this AD to address the unsafe condition on these products.