# AD 2026-21-11: General Electric Company Engines

> 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.

Page: https://www.aerscheduler.com/airworthiness-directives/2026-21-11
Maker: General Electric Company
Product: Engine
Published: October 22, 2026
Effective: November 27, 2026
Amendment: 39-23500
Supersedes: nothing

## At a glance

Quoted from the FAA's summary of this AD. The full text below is what applies.

- What it requires: 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.
- Why: The FAA is issuing this AD to prevent EEC FADEC software from automatically locking the engine at idle until it is restarted.
- Applies to: 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
- Check an aircraft by N-number: https://www.aerscheduler.com/airworthiness-directives/check

## Applies to

This AD applies to the General Electric Company (GE) Model engines identified in paragraphs (c)(1) and (2) of this AD.

  (1) CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, and CF34-8C5B1 engines with an electronic engine control (EEC) full authority digital electronic control (FADEC) part number (P/N) 4120T00P29, 4120T00P30, 4120T00P37, 4120T00P38, 4120T00P45, 4120T00P46, 4120T00P53, 4120T00P54, 4120T00P57, or 4120T00P58 installed.

  (2) CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E5A2HA, CF34-8E6, and CF34-8E6A1 engines with an EEC FADEC P/N 4120T00P42 (VIN 111E9320G43), P/N 4120T00P44 (VIN 111E9320G45), P/N 4120T00P48 (VIN 111E9320G49), P/N 4120T00P50 (VIN 111E9320G51), or P/N 4120T00P60 (VIN 111E9320G61) installed.

## What it requires

### Definitions

For the purpose of this AD:

  (1) “Group 1 engines” are GE Model CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, and CF34-8C5B1 engines.

  (2) “Group 2 engines” are GE Model CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E5A2HA, CF34-8E6, and CF34-8E6A1 engines.

  (3) An “EEC FADEC software version that is eligible for installation” on Group 1 engines is any software version that is V6.60 or later approved version.

  (4) An “EEC FADEC software version that is eligible for installation” on Group 2 engines is any software version that is V5.70 or later approved version.

### Required Actions

  (1) For Group 1 engines, within 12 months after the effective date of this AD, replace any EEC FADEC software version that is V6.50 or earlier with an EEC FADEC software version that is eligible for installation.

  (2) For Group 2 engines, within 12 months after the effective date of this AD, replace any EEC FADEC software version that is V5.60 or earlier with an EEC FADEC software version that is eligible for installation.

## Source

- The Federal Register document 2026-21590, the legal text: https://www.federalregister.gov/documents/2026/10/22/2026-21590/airworthiness-directives-general-electric-company-engines
- Current status and corrections: the FAA's Dynamic Regulatory System, https://drs.faa.gov/

_Not the official record. Whether an AD applies to one aircraft depends on its serial number, installed equipment and records, and is a certificated mechanic's determination._