AD FAA-2025-3998

The FAA is adopting a new airworthiness directive (AD) for certain General Electric Company (GE) Model CF34-8C1, CF34-8C5, CF34- 8C5A1, CF34-8C5A2, CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-8E5, CF34- 8E5A1, CF34-8E5A2, CF34-8E5A2HA, CF34-8E6, and CF34-8E6A1 engines. This AD was prompted by reports of in-flight "Engine Degraded" messages from the engine indicating and crew alerting system (EICAS) due to corrosion of the variable geometry (VG) system actuator. This AD requires removing certain electronic engine control (EEC) full authority digital electronic control (FADEC) software versions from service and installing an updated EEC FADEC software that is eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products.