US National Transportation Safety Board investigators have cleared around half the wreckage of the crashed Colgan Air Bombardier Q400 from the impact site, and aim to have the rest cleared within two days.

Both Pratt & Whitney PW150 engines have been recovered for transport tomorrow and the agency has retrieved all six propeller blades from each powerplant.

NTSB member Steven Chealander says preliminary examination shows the engine condition is "consistent with high-powered flight" at the time of the accident.

Other sections of the aircraft recovered include five of the six de-icing valves, the control columns, and the de-icing boots. Chealander says the NTSB has retrieved "good boots" and is confident of being able to determine whether they were working.

Investigators have obtained the flight plan and other documentation, a total of 30 pages, but the NTSB is yet to download the on-board aircraft communications and addressing system (ACARS) records to establish how much in-flight weather information the crew had available.

Chealander says the crew's intended landing configuration was with 15° of flap, and that initial calculations put the Q400's weight at 55,000lb (24,950kg) with a reference speed of 119kt - this rose by 20kt, to 139kt, as a result of the precautionary activation of a switch to increase stall margins. Preliminary flight-data evidence puts the aircraft's calibrated airspeed at 134kt, but Chealander warns against reading too much into the early figures.

Manufacturer Bombardier, he says, claims that the Q400 is "not susceptible" to tail stall.

While forecasts on the night of the accident, 12 February, indicated an 80% probability of icing conditions from the surface to 8,000ft, the only pilot report on severe icing was relayed from Dunkirk, some 50km southwest of Buffalo.

Chealander states that a second Colgan Air aircraft, trailing the accident flight by 27min, experienced moderate icing between 4,000-2,500ft but arrived without incident.

But the NTSB is seeking more information on weather experienced by pilots on the night of the crash, and is to issue a questionnaire in order to gather data over the next few weeks.

Source: Air Transport Intelligence news