History of Flight
On February 9, 2024, at about 1511 eastern standard time, a Bombardier CL-600-2B16 airplane, registration N823KD, was destroyed in an accident near Naples, Florida. The aircraft was returning to Naples Municipal Airport (APF) from Ohio State University Airport (OSU) on a Title 14 Code of Federal Regulations Part 135 on-demand passenger flight operated by Ace Aviation Services, doing business as Hop-A-Jet. The two airline transport pilots sustained fatal injuries. The cabin attendant and two passengers received minor injuries, and one person on the ground also suffered a minor injury.
The airplane had been serviced with 350 gallons of fuel at OSU before departure. According to ADS-B flight track data and cockpit voice recorder (CVR) communications, the flight crew contacted the APF air traffic control tower while on a right downwind leg, maneuvering for a 5-mile final approach to runway 23. At about 1509, the tower controller cleared the flight to land. At that time, the airplane was about 6.5 miles north of APF, at approximately 2,000 ft geometric altitude and 166 knots ground speed, turning onto final approach.
Review of flight data recorder (FDR) data showed three master warnings: the first at 1509:33 (L ENGINE OIL PRESSURE), the second at 1509:34 (R ENGINE OIL PRESSURE), and the third at 1509:40 (ENGINE). These warnings were indicated by illumination of a Master Warning light, a red EICAS message, and a triple-chime voice advisory.
At 1510:03, while at about 1,000 ft pressure altitude and 122 knots, the crew announced, “…lost both engines… emergency… making an emergency landing.” The controller acknowledged and cleared the airplane to land. At 1510:12, at about 900 ft and 115 knots, the crew replied, “eh we’re clear to land but we’re not gonna make the runway uh we’ve lost both engines.” No further transmissions were received. ADS-B track data ended at 1510:47, the time the airplane touched down on Interstate 75 in Naples.
Dashcam video from a vehicle traveling south on Interstate 75 captured the final moments. The airplane descended in a shallow left turn, aligned with southbound traffic, and touched down with the left main landing gear first in the center lane, then the right main gear in the right lane. It continued to the right, through the breakdown lane, down a slight embankment, struck a non-frangible highway sign, veered further right, and impacted a concrete sound barrier wall. Dust, fire, smoke, and debris obscured the airplane after impact.
After the airplane came to rest, the cabin and emergency exits were blocked by fire. The cabin attendant coordinated the successful egress of herself and the passengers through the baggage compartment door in the tail section.
Aircraft Information
The airplane, a Bombardier CL-600-2B16, was manufactured in 2004 and powered by two GE CF34-3B turbofan engines. According to FAA and maintenance records, it was operated by the previous owner from 2005 to 2020, based primarily at Grantley Adams International Airport (BGI), Bridgetown, Barbados. It was registered to the accident operator on May 21, 2020, and transferred to the operator’s Part 135 certificate on June 3, 2021. At that time, the airplane and engines had about 6,939 total flight hours and 2,653 cycles since new. At departure from OSU on the accident day, totals were about 9,761 hours and 4,444 cycles. With the accident operator, the airplane was primarily based at Fort Lauderdale Executive Airport (FXE), Florida.
The airplane and engines were maintained under the operator’s FAA-approved Continued Airworthiness Maintenance Program, in accordance with Bombardier’s CL-604 Time Limits/Maintenance Checks Manual and GE’s service manual (SM) SEI-780. The engines were maintained and inspected on an “On-Condition” basis.
Previous Hung Start Event
On January 15, 2024 (25 days before the accident), pilots reported intermittent hung starts on both engines while preparing for taxi. A hung start is defined as light-off followed by abnormally slow acceleration and rotor speed stabilization below idle. Troubleshooting included draining and testing fuel (no contamination found), replacing both engine fuel filters (no defects observed), and functional checks (no anomalies noted). The operator used GE SM SEI-780 72-00-00 “Fault Isolation 07 Hung Start or Slow Start” for troubleshooting. The fault isolation flowchart contained 27 main logic blocks; block 21 referenced MP 68 to pressure check the variable geometry (VG) system. The MP 68 pressure test was not performed because the flowchart criteria to discontinue testing were met (engines started and no anomalies identified). With concurrence from the engine manufacturer, the airplane was returned to service. Both engines started and operated without issues for 33 flights over the next 25 days.
Engine Trend Monitoring
The operator participated in an engine trend monitoring program managed by the engine manufacturer. Parameters such as N1 and N2 speeds, vibration levels, oil temperature and pressure, and ambient conditions were collected for every flight and analyzed to calculate takeoff exhaust gas temperature hot day margin and monitor performance shifts. Service Bulletin (SB) 71-1000 R01 directed performance downloads every 50 flight cycles. The engine manufacturer did not issue any notices to the operator regarding trend monitoring data before or after the January 2024 hung starts.
Wreckage and Impact Information
Examination of the accident site revealed tire marks on the southbound lanes of Interstate 75 consistent with the left main landing gear. The airplane came to rest about 1,000 ft past the initial touchdown point, upright in the grass area between the breakdown lane and the sound barrier wall, facing north (opposite the direction of travel).
The forward fuselage was consumed by postimpact fire. All major components were accounted for; the ground was fuel-soaked with an odor consistent with Jet A fuel. The cockpit center console was separated from the main wreckage. Both engine thrust levers were found near the IDLE stop position. The flap selector handle was consistent with 45° flap extension.
The left wing was nearly entirely consumed by fire. Flap actuator jack screws were consistent with 45° extension. The left wing fuel boost pump was not found. The right wing exhibited leading edge damage from impact with a vertical steel I-beam of a highway sign; the front spar was severed in that area. The outer portion of the right wing was impact-separated; the inboard portion was thermally damaged. The right wing fuel boost pump was located nearby and showed thermal damage.
The tail section was largely intact but damaged by fire. The aft-mounted engines were secure in their mounts. The vertical stabilizer, horizontal stabilizer, and elevator control surfaces were intact.
About 16 ounces of liquid with odor and appearance consistent with Jet A fuel was drained from the aft tail fuel tank; the sample contained about ½ ounce of what appeared to be water. The auxiliary power unit fuel filter bowl was inspected; no debris was noted in the drained fuel and the filter appeared clean. Fuel was retained for further analysis.
The engines and pylons were cut from the airplane for recovery. A fuel sample from the No. 1 engine main supply line was collected; no fuel was released when the No. 2 engine main supply line was cut.
No. 1 (Left) Engine
The left engine fan and core assemblies displayed thermal damage from postimpact fire; some cowling was consumed. All fan blades were full length and intact with no impact damage to leading edges. Stage 4 low-pressure turbine blades appeared intact and straight. Cowl doors were opened; no case uncontainment was evident. No thermal distress was noted aft of the gearbox. The MFC throttle lever spindle, lever arm, and push/pull rod were connected and undamaged; red alignment marks indicated an IDLE throttle position.
The fuel filter appeared clean, with no debris or foreign material within the pleats. Fuel samples from various points were clear and consistent with Jet A. The fuel flow transmitter had unobstructed inlet and outlet ports. Fuel injectors showed normal operating signatures. One fuel igniter was removed and showed no anomalies.
Visual examination of the MFC, main fuel pump, and main fuel inlet port revealed no anomalies. The oil filter was in good condition with no particles in the pleats.
No. 2 (Right) Engine
The right engine spinner cone, access cowls, translating assembly cowls, and exhaust fairing displayed thermal damage. All fan blades were full length with minimal leading edge or tip damage. Stage 4 low-pressure turbine blades were full length and undamaged. The MFC throttle lever and linkage were observed forward of the IDLE stop. Core cowl doors were removed; no case uncontainment was observed.
The fuel filter bowl showed thermal discoloration; the filter was clean with no debris. Fuel samples from various points were collected; fuel from the filter bowl and heat exchanger had a yellowish tint, others were clear. Odor was consistent with Jet A. Samples from the MFC and main fuel pump contained small black debris, consistent with introduction during removal.
Fuel injectors showed normal operating signatures; one igniter was removed and showed no anomalies.
Visual examination of the MFC and main fuel pump revealed no anomalies. The main fuel inlet port had a small yellow debris particle. The oil filter appeared in good condition with no particles in the pleats.
Additional Information
During the investigation, the engine manufacturer issued several safety changes: 1. On May 14, 2024, SB 72-0345 R00 required a one-time inspection of CF34-BJ engines that had a hung start in the last 24 months to identify possible interface corrosion/obstruction. As of May 2025, 34 engines were inspected; seven failed and were removed from service—four from the accident operator’s fleet and three from two other operators. 2. On May 30, 2025, SB 72-0347 R00 provided instructions for a borescope inspection of the compressor case inner diameter and variable geometry system functional check, recommending all CF34-3BJ engines be inspected within 48 months. As of March 2026, 1,085 engines were inspected; one failed and was removed from service. 3. On February 6, 2026, SB 71-0000 R03 introduced changes to special requirements for sea/salt environments or if corrosion is present on external areas. 4. The engine manufacturer planned to introduce a periodic “HPC case localized BSI and VG Functional Check (MP 68)” task to the Chapter 05 Airworthiness Limitations section of SM SEI-780, to be conducted every 48 months. 5. On August 12, 2024, the engine manufacturer issued an incremental change to Fault Isolation 07, making the MP 68 pressure check one of the first tasks before removal of any line-replaceable unit.
Flight Recorders
The airplane was equipped with an L3 FA2100 FDR. The downloaded recording contained more than 150 hours of data spanning 56 flights, including the accident flight (duration about 2 hours 20 minutes). The FDR did not capture thrust lever position or autothrottle parameters.
During the descent, the decrease in power was similar in rate to previous decreases. At 15:09:22, N2 increased on both engines, consistent with thrust lever command increase. At 15:09:23, N2 rolled back on both engines to a sub-idle state, and ITT increased for the rest of the recording. The airplane decelerated immediately, consistent with engine power loss. Flaps were selected to 45°, and selected airspeed changed to 140 knots.
At 15:09:33, a No. 1 engine oil pressure warning was recorded, followed by No. 2 at 15:09:34. Airspeed was less than 130 knots. Pitch was commanded down, and descent rate exceeded 1,500 ft per minute. At 15:09:40, an engine warning was recorded, consistent with ITT exceeding the redline of 889°C. From 15:09:50, fuel flow values for both engines became intermittent (flowmeter does not report below 200 pounds per hour).
Stick shaker activated for two seconds at 15:10:21 at 490 ft and 112.5 knots. Pitch reduced after activation. The airplane touched down at 15:10:47 at about 110 knots, in a 15° left bank, with about 1.5° nose-up pitch.
Historical FDR Data Review
Engine data from all 56 recorded flights were reviewed. The deceleration rate during the accident flight was similar to previous descents. Engine performance was not consistent with a fuel cutoff event, combustor blowout, or flameout.
Comparison to Previous Hung Starts
FDR data from January 15, 2024, recorded ten hung starts between the two engines (eight fully stagnated). A comparison showed that the engines’ fuel and ITT behavior during the accident flight was consistent with behavior during the hung start rollbacks. Additionally, maintenance records noted seven other hung start events in the 10 years before the accident.
Medical and Pathological Information
An autopsy of the captain, performed by the District Twenty Medical Examiner, Collier County, Florida, determined the cause of death as inhalation of superheated gases. (Manner of death was not specified in the source.)