Overview
- The NTSB concluded internal corrosion in variable-geometry components caused near-simultaneous compressor stalls that led to a fatal Challenger 604 accident and prompted FAA rulemaking.
- The FAA issued a notice of proposed rulemaking that would require borescope inspections and operational checks for specified GE CF34 engines, a proposal that covers more than 1,100 in-service engines.
- Hop-A-Jet filed formal comments during the NPRM comment period urging the FAA to mandate visual borescope corrosion inspections, require reporting of corrosion findings, and reinspect engines that were cleared under procedures that did not check corrosion-prone areas.
- The company says archived borescope images reviewed after the accident showed corrosion that had not been reported to the operator, highlighting that manufacturer-authorized vendors often perform proprietary inspections without guaranteed operator notification.
- If the FAA accepts these changes, operators could see new inspection protocols, tighter reporting rules, and more frequent functional checks in salt-exposed fleets, which would affect maintenance costs and how crews detect and respond to internal engine corrosion.