The damaged flight data and cockpit voice recorders recovered from the wreckage of the Crossair Saab 340B which crashed shortly after take-off from Zurich on 10 January have been dispatched to the Transport Safety Board of Canada (TSB) for analysis.
All 10 passengers and crew were killed in the Swiss regional's first fatal accident in its 25-year history.
Swiss authorities say it remains unclear whether it will be possible to extract data from the recorders, which were found buried 3m (10ft) deep in wet ground at the accident site. The aircraft had been retrofitted by Crossair with an AlliedSignal 60-channel solid-state digital data recorder which, if readable, should provide detailed information.
Flight LX498, a scheduled service from Zurich to Dresden in Germany, departed just before 17.55 local time carrying seven passengers and three crew. The 10-year-old aircraft (HB-AKK) was one of 14 of the type operated by the airline. The type will begin to be phased out later this year when deliveries of Embraer RJ-145 regional jets begin.
Ground temperature was 2°C, with "almost no wind" and a "fairly low" cloudbase at around 1,000ft, according to Crossair vice-president flight operations, Captain André Dosé.
The captain was a Moldovan national who was trained to fly the Saab 340 by Crossair while working for Moldavian Airlines. The Slovakian co-pilot joined the carrier last August, having previously flown Saab 340s for Bratislava-based Tatra Air.
Controllers lost radar contact around 2min after take-off. Up to that point all communications were routine. The aircraft crashed in a field 7km (3.8nm)away, near the village of Niederhasli.
The only significant clue to emerge from radar data is that during the final few seconds before impact the aircraft executed a turn to the right, at a point where it should have been making a 180° turn to the left towards the Zurich east VOR.
Swiss Federal Aircraft Accident Investigation Office on-site investigator Daniel Knecht says the aircraft is estimated to have gone out of control at an altitude of around 4,700ft, meaning that its height above the ground was 2,500-3,000ft.
Source: Flight International