20030413011929A

(-23) During a flight that was to be an IFR training flight departing from Sedona to williams gateway a Beech bonanza A-36 was destroyed after failing to get airborne after takeoff. The aircraft had three people on board: a private pilot, the instructor, and one observer in the back seat. Witnesses on the airport had observed the aircraft on the runway attempting to takeoff without enough power. The aircraft continued down the runway until it was observed the aircraft rotated 4/5 down the runway, the witness observed that the attitude of the aircraft was high but the mains were still on the runway. At the end of the runway the aircraft lifted about 2 to 3 feet in an extreme nose high attitude. The airport boundary at the end of the runway drops off to a shear cliff of 400 feet. The aircraft then continued into the ravine and impacted the opposite bank in an apparent stall and was destroyed by fire. All on board perished. Interviews with the witnesses, including some pilots who had experience in this aircraft type, stated that it was obvious to them that the aircraft was not producing enough power. The engine was not running rough, just that the RPM seemed low. An evaluation of the engine revealed that the spark plugs had evidence of lean condition. The powerplant representative had examined the engine and confirmed that the fuel system used a compensating aneroid, this meant that the engine should not have been leaned for takeoff at a high altitude airport. An interview with other students and instructors whom had flown with the instructor in the accident aircraft revealed that she would teach leaning in this and the other bonanza. The second bonanza operated by the flight school does not have the compensating aneroid and would require leaning for best performance. Some other factors in the accident were the checklists for the aircraft did not require that this aircraft be full rich for takeoff. Also the instructor's style was to let the student make minor mistakes and allow the student to discover the error on their own. The time between the student noticing the error and the time needed to abort the takeoff was too short; however, manifold pressure and RPM problems should have been evident. This flight school had already changed its training procedures to include more aircraft specific operations of systems and also more instructions for go-no go decisions, and to be more aggressive in making those decisions early enough in the takeoff roll. Tests were performed in farminton NM in a similar aircraft with similar conditions. Several profiles were tested to determine if the fuel mixture setting and the RPM settings would contribute to this accident. It was discovered that the aircraft would in every case reach flying speed no matter how the mixture and propeller settings were used. The only scenario that best looked like what witnesses had observed was to try and takeoff with the RPM set at cruise (2300), the mixture control set to lean, and the flaps set to full down. The flaps in the wreckage was found in the 5-degree position. It could not be determined if the flaps were in transit later in the takeoff roll. It could be possible that if the flaps were set to full down and discovered too late in the aircraft roll to abort before the end of the runway. The instructor could have tried to retract the flaps at the last minute. This could account for the settling that witnesses had seen. All those factors notwithstanding, there still was the issue that it was obvious to the witnesses that the aircraft was not performing as expected and the pilots continued with the takeoff anyway.