AD 2022-08-06 Airworthiness Directives; General Electric Company Turbofan Engines

This AD applies to General Electric Company (GE) CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 model turbofan engines installed on an airplane that has accumulated 250 or more parked days outdoors within the 24 months prior to the effective date of this AD.

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

(1) Torque Check: CF34-8C Model Turbofan Engines With Full Authority Digital Engine Control (FADEC) Software (SW) Below Version 6.60, and All Affected CF34-8E Model Turbofan Engines (i) If the affected engine is installed on an airplane that was parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, within 30 flight hours (FHs) or 5 calendar days, whichever occurs first after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 440 FHs after the effective date of this AD. (ii) For affected engines not requiring the performance of a rotational torque check by paragraph (g)(1)(i) of this AD, if the affected engine is installed on an airplane that was parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, within 200 FHs or 35 calendar days, whichever occurs first after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 880 FHs after the effective date of this AD. (iii) For affected engines not requiring the performance of a rotational torque check by paragraphs (g)(1)(i) or (g)(1)(ii) of this AD, before exceeding 880 FHs after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 1,680 FHs after the effective date of this AD. (2) Torque Check: CF34-8C Model Turbofan Engines With FADEC SW Version 6.60 or Above Installed on an Airplane That Is in Service as of the Effective Date of This AD (i) If the affected engine is installed on an airplane that was parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, within 200 FHs or 35 calendar days, whichever occurs first after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 10 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 880 FHs after the effective date of this AD. (ii) For affected engines not requiring the performance of a rotational torque check by paragraph (g)(2)(i) of this AD, if the affected engine is installed on an airplane that was parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, before exceeding 440 FHs after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed while parked less than or equal to 50 miles from a saltwater coastline for 250 or more parked days, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 880 FHs after the effective date of this AD. (iii) For affected engines not requiring the performance of a rotational torque check by paragraphs (g)(2)(i) or (g)(2)(ii) of this AD, before exceeding 880 FHs after the effective date of this AD, perform a rotational torque check of the actuating linkage assembly. If an airplane has two affected engines installed, operators may perform the rotational torque check of the actuating linkage assembly on the second engine before the second engine exceeds 1,680 FHs after the effective date of this AD. (3) Torque Check: All Affected Engines That Are Not currently in Service If the affected engine is installed on an airplane that was parked outdoors for 250 or more parked days within the 24 months prior to re-entering service, or if the engine was off-wing and stored outdoors for 250 or more days within the 24 months prior to reentering service, before further flight, perform a rotational torque check of the actuating linkage assembly. (4) Replacement of the Compressor Inlet Guide Vane (IGV) Outer Shroud Bushing and Vane Spindle Bushing If the actuating linkage assembly does not pass any rotational torque check required by paragraphs (g)(1) through (3) of this AD, before further flight, remove the compressor IGV outer shroud bushing and vane spindle bushing and replace with a zero cycles since new compressor IGV outer shroud bushing and vane spindle bushing. (5) Service Information for Performance of the Rotational Torque Check and Replacement of the Compressor IGV Outer Shroud Bushing and Vane Spindle Bushing Use the Accomplishment Instructions, paragraph 3.A.(1)(c), of GE CF34-8C Service Bulletin (SB) 72-0356 R00 or GE CF34-8E SB 72-0244 R00, both dated February 15, 2022, as applicable to the engine model, to perform the actions required by paragraphs (g)(1) through (4) of this AD.

This AD was prompted by an “Engine Degraded” message received in-flight from the Engine Indicating and Crew Alerting System (EICAS), and a subsequent investigation by the manufacturer that revealed corrosion of the variable geometry (VG) system actuator. The FAA is issuing this AD to detect corrosion of the VG system actuator. The unsafe condition, if not addressed, could result in failure of one or more engines, loss of engine thrust control, and reduced control of the airplane.

None.