The Federal Aviation Administration (FAA) issued a notice of proposed rulemaking (NPRM) that would require new inspections and operational checks for General Electric CF34-series engines, following a 2024 fatal business jet accident that raised concerns about undetected corrosion.
Published May 1, the proposal would affect more than 1,100 engines installed on Bombardier Challenger 600 series aircraft and Bombardier CRJ200 airliners. The NPRM outlines a combination of borescope inspections, variable geometry (VG) system functional checks, and, for some engines, recurring restart tests—measures that vary by engine model and configuration.
While the FAA does not directly cite a specific accident, the action is widely tied to the February 2024 crash of a Bombardier Challenger 604 operated by Hop-A-Jet. The aircraft experienced a near-simultaneous loss of thrust in both engines on approach, resulting in two fatalities.
Investigators found that corrosion within the engines’ VG system components can restrict movement, causing them to fall out of schedule and increasing the risk of compressor instability and thrust loss. The National Transportation Safety Board (NTSB) concluded that corrosion in both engines led to compressor stalls and a total loss of thrust. The investigation also cited insufficient maintenance guidance for detecting corrosion during prior troubleshooting.
Under the proposed directive, certain engines would require inspection before further flight, while others would be subject to phased compliance periods of up to two years. Some configurations would also mandate restart testing at regular intervals, potentially as often as every three months. If discrepancies are found, required actions could include additional maintenance or engine removal.
The FAA estimates the proposal would impact approximately 1,152 U.S.-registered engines. Public comments are open through mid-June 2026, after which the agency will consider final rulemaking.