The cockpit voice recorder (CVR) failed to record before and during the January 31 crash of a medevac Bombardier Learjet 55 in Philadelphia and may not have recorded on any flights for several years, according to the preliminary NTSB report released yesterday. After departing Northeast Philadelphia Airport (KPNE) at 6:07 p.m. EST, the Learjet—headed to Springfield-Branson National Airport (KSGF) in Missouri—went down approximately one minute after takeoff, killing all aboard and one person on the ground.

Per Mexico’s Federal Civil Aviation Agency (Agencia Federal de Aviación Civil [AFAC]) rules drafted based on ICAO Annex six documentation, Part 25 aircraft with an mtow of 5,500 kg or more operating in Mexican airspace must have a CVR. In addition, foreign-registered multi-engine turbine aircraft with more than six passenger seats, as well as any foreign-operated air charter aircraft flying in Mexican airspace, must be equipped with a CVR.

Jet Rescue Air Ambulance is fully certified in both Mexico and the U.S. under FAA regulations; it has bases in Mexico City and in Miami, Florida. The Part 25-certified Learjet 55 has a maximum capacity of 10 passengers, mtow of 21,500 pounds (roughly 9,752 kg), and a range of 2,165 nm. There is no information about whether the accident airplane may have been operating with an inoperative CVR under a minimum equipment list.

Both pilots, two medical crewmembers, and two patients onboard the Part 129 air ambulance flight died in the accident. One person on the ground was also killed while four people were seriously injured and 20 more sustained minor injuries. The crew did not make any distress radio calls during the flight. There was a 400-foot cloud ceiling and six statute miles of visibility at the time of the accident. 

Security camera footage of the accident showed a large explosion as the aircraft crashed in a residential/commercial area. According to the report, the debris field extended 1,410 feet by 840 feet. “The CVR was recovered from the initial impact crater under eight feet of soil and debris and was sent to the NTSB Vehicle Recorders Laboratory in Washington, D.C., for processing and readout,” the report states.

Containing a 30-minute tape-based recorder, the CVR sustained significant damage from both the impact and water. The laboratory cleaned and repaired the device and then discovered that nothing had been recorded during the flight, and “during the audition it was determined that the CVR had likely not been recording audio for several years.”

The aircraft wreckage has been recovered for further examination, and the aircraft’s onboard enhanced ground proximity warning system computer, “which may contain flight data in its nonvolatile memory, was shipped to the manufacturer’s facility for evaluation and to determine whether any relevant flight data could be recovered.” Investigation of the accident is ongoing.