Fire of Unknown Origin Led to 2024 Citation X Accident

A Cessna Citation X+ experienced an in-flight fire and electrical failure that investigators could not trace to a specific cause, leading to loss of control during landing in Jamestown, New York, on Aug. 5, 2024, according to a newly released NTSB final report. The business jet was destroyed after it struck terrain short of the runway and then was consumed by post-impact fire. Only the two pilots were aboard; one sustained serious injuries while the other received only minor injuries.

The flight crew was attempting a precautionary landing at Chautauqua County/Jamestown Airport (KJHW) when the accident occurred shortly after 10 a.m. local time. The airplane had departed Chautauqua County/Dunkirk Airport (KDKK) in Dunkirk, New York, about 10:03 a.m., bound for Fort Lauderdale Executive Airport (KFXE) in Florida. The purpose of the flight was to retrieve airplane parts and a mechanic for maintenance on another company aircraft. 

About three minutes after departure, while climbing, the copilot reported smelling an electrical burning odor that he said dissipated. Both pilots subsequently smelled smoke, and multiple crew alerting system (CAS) messages appeared in quick succession. The crew diverted toward KJHW, but as the pilot maneuvered the airplane, he had difficulty maintaining airspeed and pitch control, and radio communications with air traffic control grew intermittent.

The pilot’s primary flight display began showing fault indications, and he reported losing trim control; attempts to use secondary trim were unsuccessful. The copilot separately described the airplane accelerating past 250 knots, with the nose trimmed down, as they descended through 10,000 feet, and said he heard the trim system’s audible “clacker” warning before losing contact with a second communication radio.

During the approach, the airplane struck terrain and runway approach lighting about 200 feet short of Runway 25, continued along the runway past the Runway 13/31 intersection, and came to rest off the left side of the pavement, roughly 2,150 feet beyond the point of initial impact. A post-impact fire ensued, and the pilots exited through the main cabin door after the copilot initially was unable to open it. The pilot was seriously injured, and the copilot sustained minor injuries. Investigators found no evidence of pre-impact mechanical anomalies with either engine, and the copilot reported no engine-related CAS messages during the flight.

The cockpit voice recorder, recovered and successfully downloaded, captured three flights, including an earlier flight that day in which the crew returned to KDKK after a scheduling change; the recording indicated that the crew did not complete checklists during that earlier flight. A separate aircraft recording system was also recovered, but thermal damage to its storage chip prevented data recovery.

Investigators focused their examination on wiring located aft of the rear pressure bulkhead, where several conductors showed arcing, welding, and beading. One wiring bundle in that area was identified as containing horizontal-stabilizer trim circuits; a second contained stabilizer position-sensor signal wiring, and a coaxial cable feeding the No. 2 VHF communication antenna was also routed through the same corridor. The No. 2 battery, located nearby, displayed arcing signatures, but further examination determined that the arcing likely originated outside the battery case, and fractured battery cable conductors were consistent with mechanical rather than electrical failure.

Investigators pointed to the intermittent smoke smell reported by the crew, the absence of any smoke observed by witnesses or captured on video during the approach, and the limited external sooting found on the airframe as evidence that the fire likely started inside the airplane, in a location inaccessible to the crew, and had not burned through the fuselage before landing.

According to the airframe manufacturer, the near-simultaneous appearance of multiple CAS messages was “consistent with the way the installed avionics systems would respond to the loss of electrical power or data communication,” the report stated, since several affected systems shared wiring routed through a common corridor in the aft fuselage before branching to individual components.

Maintenance records showed that the airplane had undergone service at a manufacturer facility on July 11, 2024, less than a month before the accident, including repair of the No. 2 battery, a functional check of the horizontal stabilizer trim actuator, and corrosion inspections of the wings and stabilizers. That work found that the No. 1 battery had experienced thermal runaway on five cells, and the No. 2 battery had failed a capacity test; both were serviced according to manufacturer guidance. Inspectors also noted that the main electrical junction box cover was missing four retaining studs and 32 stud-retaining rings, which were replaced. Post-accident testing of the horizontal stabilizer trim actuator, including load testing to its rated maximum, found the unit fully functional with no evidence of backdriving.

Weather at KJHW around the time of the accident was reported as visual conditions, with 10 miles visibility, a few clouds at 3,700 feet agl, and wind out of 220 degrees at 6 knots. Witnesses told investigators the approach appeared normal until the airplane landed short of the runway threshold and hard, and none reported seeing smoke trailing the aircraft; video from a nearby business likewise showed no visible smoke during the approach.