The United States Federal Aviation Administration (FAA) is planning to require owners and operators to inspect General Electric CF34 engines. The proposal applies to an estimated 1,152 engines installed on Challenger 600 and CRJ200 family aircraft and was prompted by a dual-engine power loss event in 2024.

Although not detailed by the FAA, the event has been linked to the crash of a Challenger 604 operated by Hop-A-Jet Worldwide Jet Charter earlier that year.

Through a notice of proposed rulemaking (NPRM) released on April 30, the FAA proposes a new airworthiness directive (AD) covering CF34-1A, CF34-3A, CF34-3A1, CF34-3A2, and CF34-3B engines. These power Challenger 600-series aircraft across all variants, along with a smaller number of CRJ200-family jets.

“This proposed AD was prompted by a dual-engine power loss event and a subsequent manufacturer investigation, which revealed corrosion in the high-pressure compressor (HPC) case affecting the variable geometry (VG) system,” the NPRM states.

The AD would require several tests, including borescope inspections for corrosion and, depending on the results, VG system functional checks for pressure evaluation. Corrective actions could include engine retirement. The directive would also require incorporation of the VG system check into the engine maintenance manual's airworthiness limitations.

Depending on engine type and serial number, owners and operators could be required to complete inspections before further flight, within one year, or within two years. In addition, some engines would be subject to restart tests every three months.

The FAA will accept comments on the proposed AD until June 15, 2026.

Hop-A-Jet Challenger crash

Although the FAA does not detail the triggering event in the NPRM, a 2005-built Challenger 604 equipped with CF34-3B engines and operated by Hop-A-Jet crashed near Naples Municipal on February 9, 2024, following a dual-engine failure. The accident killed two company pilots.

The crash prompted Hop-A-Jet and affiliated companies to file a lawsuit on September 26, 2025, against General Electric, Bombardier Aerospace, Learjet, and other aviation service providers. The Part 135 operator alleges negligence and concealment, claiming General Electric had been aware since 2019 that a key VG system in the CF34 engine family was prone to hidden corrosion.

On April 23, 2026, the National Transportation Safety Board (NTSB) released the final report on the crash. “Corrosion of both engines' VG system components led to operation in an off-schedule position and resulted in near-simultaneous sub-idle rotating compressor stalls on approach, subsequent loss of thrust in both engines, and an off-airport landing,” the report states.

“Contributing to the accident was inadequate fault-isolation guidance by the engine manufacturer, which prevented identification of corrosion buildup in VG system components during troubleshooting of hung-start events in both engines about one month before the accident,” the report adds.

Speaking to AIN before the FAA's proposed rulemaking was released, Hop-A-Jet president Barry Ellis said he was surprised no recommendations were issued by NTSB. While welcoming General Electric's revised service bulletins and maintenance manual updates addressing corrosion-detection procedures, issued on October 30, 2025, he called for further action.

“We believe that, in the interest of safety, there needs to be an FAA mandate to adhere to these service bulletin procedures, and to go further,” Ellis said, adding that this could take the form of an AD requiring more frequent borescope inspections and VG system pressure tests.

ch-aviation contacted General Electric, Bombardier, and Hop-A-Jet for comment.