AD 2023-24-04 Airworthiness Directives; Honeywell International Inc. Engines

Models named: AS907-1-1A, AS907-2-1G. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Honeywell International Inc. (Honeywell) Model AS907-1-1A and AS907-2-1G engines.

Comply with this AD within the compliance times specified, unless already done.

(1) For AS907-1-1A engines with an electronic control unit (ECU) having part number (P/N) 2119576-1011 and software version AS907_1001 installed, before exceeding the applicable compliance time in Table 1 to paragraph (g)(1) of this AD, either replace software version AS907_1001 with a software version eligible for installation; or replace the ECU with an ECU eligible for installation. Either the software or ECU must be replaced for all four ECUs installed in both airplane engines at the same time. Note 1 to paragraph (g)(1): Guidance for removing and replacing the ECU software or removing and replacing the ECU may be found in Honeywell Service Bulletin (SB) AS907-76-9031, Revision 2, dated May 15, 2022. Table 1 to Paragraph ( g )(1)—Model AS907-1-1A Engines Engine time since new (TSN) Compliance time Greater than 5,000 hours TSN Within 12 months or 400 flight hours (FH) after the effective date of this AD, whichever occurs first. 3,000 to 5,000 hours TSN Within 18 months or 600 FH after the effective date of this AD, whichever occurs first. Fewer than 3,000 hours TSN Within 24 months or 800 FH after the effective date of this AD, whichever occurs first. (2) For AS907-2-1G engines with serial numbers (S/N) P130101 through P130240 that have not incorporated Honeywell SB AS907-72-9063, and for AS907-2-1G engines with S/Ns P130241 through P130336, and S/Ns P130101 through P130240 that have incorporated Honeywell SB AS907-72-9063, before exceeding the applicable compliance time in Table 2 to paragraph (g)(2) of this AD, replace any installed ECU having P/N 2119576-3001 or P/N 2119576-3002 with an ECU eligible for installation. All four ECUs installed in both airplane engines must be replaced at the same time. Note 2 to paragraph (g)(2): Guidance for removing and replacing the ECU may be found in Honeywell SB AS907-76-9014, Revision 6, dated October 10, 2022. Note 3 to paragraph (g)(2): Guidance for converting a standard flow compressor to a high flow compressor for improving surge margin may be found in Honeywell SB AS907-72-9063, Revision 1, dated July 31, 2019. Table 2 to Paragraph ( g )(2)—Model AS907-2-1G Engines Engine type Compliance time Standard Flow Compressor AS907-2-1G engines (engine S/Ns P130101 through P130240 that have not incorporated Honeywell SB AS907-72-9063) Within 2 years or 800 FH after the effective date of this AD, whichever occurs first. High Flow Compressor AS907-2-1G engines (engine S/Ns P130241 through P130336 and engines that have incorporated Honeywell SB AS907-72-9063) Within 7 years or 2,800 FH after the effective date of this AD, whichever occurs first.

This AD was prompted by reports of compressor surge, including a dual engine compressor surge, during takeoff climb out through a steep temperature inversion, which caused a loss of engine thrust control. The FAA is issuing this AD to prevent loss of engine thrust control. The unsafe condition, if not addressed, could result in reduced controllability of the airplane, loss of control of the airplane, reduced ability of the flight crew to maintain the safe flight and landing of the airplane, and loss of the airplane.

None.