NTSB Probable Cause

THE PILOT-IN-COMMAND'S DECISION TO CONTINUE TAKEOFF WITH A KNOWN DEFICIENCY IN THE AIRPLANE - LOW POWER ON BOTH ENGINES WHICH RESULTED FROM OPEN COMPRESSOR SURGE VALVES. THE PILOT SUBSEQUENTLY FAILED TO MAINTAIN AIRSPEED WHILE MANEUVERING IN A TURN RESULTING IN AN IN-FLIGHT LOSS OF CONTROL AND A STALL/SPIN.