US investigators have disclosed that the cockpit-voice recorder on the ambulance Learjet 55 which fatally crashed in Philadelphia failed to capture audio from the flight.
The 30min recording tape had required extensive cleaning and repair after the device – which suffered substantial impact damage and liquid ingestion – was retrieved from the crash site.
But the National Transportation Safety Board says it “did not record” the 31 January flight, adding that analysis of the tape’s contents indicated it had probably “not been recording audio for several years”.
The aircraft was also fitted with an enhanced ground-proximity warning system which is undergoing evaluation to determine whether its memory contains any relevant flight data.
Bound for Springfield with six occupants, the Mexican-registered Jet Rescue aircraft (XA-UCI) had departed from Northeast Philadelphia airport.
After take-off from runway 24, the jet climbed to the southwest before turning slightly right and entering a gradual left turn, according to ADS-B surveillance data.
It continued in the left turn, reaching an altitude of 1,650ft before descending rapidly. The aircraft had reached 242kt groundspeed at 1,275ft when the data ended.
No distress call was received. The flight lasted about 1min.
Analysis of damage to a sign inflicted as the jet came down indicates a descent angle of 22°. The aircraft struck the ground in a residential and commercial area, disintegrating on impact.
“Wreckage and debris penetrated numerous homes, commercial buildings, and vehicles in the area, resulting in extensive fire and impact damage,” says the inquiry.
None of those on board the jet – two pilots, two medical personnel, and two passengers – survived. The crash also resulted in a fatality on the ground, while 24 other people were injured, four of them seriously.
Such was the force of the crash that the cockpit-voice recorder was located 8ft beneath soil and debris at the point of impact.
According to the aircraft’s operator, the captain had accumulated 9,200h total flight time while the second pilot had around 2,600h. Both were type-rated on the Learjet 55.
Instrument conditions prevailed at the time of the take-off, in darkness with an overcast cloud base just 400ft above ground level. Visibility was around 10km.
