Cessna 340-A | N888MT

The DTSB determines the Probable Cause of this accident to be pilot error, in that the private pilot did enter the left downwind for runway 18 at KGPH at a speed below DMMS. He extended the landing gear, turned left base, and pulled aft on the control yoke in an ever decreasing speed. The entire traffic pattern was flown both too low and too slow, and the aircraft stalled and rolled left, impacting the ground and immediately erupting in fire. Both occupants were alive initially but could not get out of the burning aircraft. The cause of this accident is clearly a pilot error loss of speed awareness, and prolonged turning flight well below DMMS.

The DTSB recommends that all pilots of all aircraft become aware of DMMS and Vref for their aircraft, and that they commit to marking their airspeed indicators for both. At no time should flight be permitted to bank more than 30 degrees, or fly below the DMMS bug. Most airspeed indicators are marked with stall speeds, which may or may not be accurate for wings level stall. The DMMS reference protects pilots in coordinated flight up to 30 degrees bank. The DTSB recommends that all pilots commit to avoid flight below DMMS until on final, when they can slow to Vref to Vref plus 5.