United States of America

A maintenance supervisor and two pilots noted that the left engine did not respond normally while being started. Aft starting, the pilot taxied to runway 10 for an IFR departure. Since the taxiway did not extend to the end of the runway, the pilot of another aircraft waited on the taxiway, just short of the runway, approximately 2,967 feet from the end. He observed smoke coming from the left engine of the MU-2 and reported this info on the unicom frequency. He reported that the MU-2 continued and rotated for takeoff approximately 200 to 250 yards east of his position. Reportedly, the aircraft climbed to approximately 300-400 feet afl, then turned left toward higher terrain. After turning, it enter what two witnesses described as a VMC roll, then crashed and burned. An examination of the airframe revealed no preimpact mechanical failures. A teardown of the left engine revealed that a turbine bearing, pn 3101092-1, had been misaligned and subsequently began to fail, damaging the 2nd and 3rd stages of the turbine section. The airport elev was 6,597 feet. The computed takeoff roll was 1,620 feet and the computed accelerate stop distance was 3,100 feet. The landing gear and selector found in down position. The aircraft was destroyed and all six occupants were killed.

The flight was conducting single-engine flight tests with the inboard gear doors removed and was being photographed by a chase aircraft. At the end of the tests the pilot was unable to restart the left engine and returned for a single-engine landing. The pilot overshot the landing attempt and executed a single-engine go-around. The pilot then reported he had a gear problem. An occupant of the chase aircraft reported that the main gear were hanging 75 to 80 degrees from the horizontal. A company employee at the airport reported that the nose gear was about 10° aft of the normal down and locked position. The aircraft continued on a wsw heading away from the airport, passing over several suitable emergency landing sites while in a slow descent until colliding with the guy/grounding wire atop a powerline pole located 4 miles wsw of the arpt. The aircraft was destroyed and both occupants were killed.

The aircraft departed Charleston in the early afternoon on a training mission, carrying a crew of nine. Weather conditions worsened en route with sky overcast at 4,500 feet, top of clouds at 8,000 feet and zero visibility below 4,500 feet due to rain falls and fog. The airplane struck the slope of Mt Johns Knob (4,908 feet high) located at the Tennessee - North Carolina border. The wreckage was found 118 feet below the summit and all nine occupants were killed. At the time of the accident, the visibility was below minimums for military training mission.

Before takeoff, the pilot filed a company flight plan for a VFR flight from Boise to Salmon, ID. He reported that during initial climb, the engine surged, then seemed to return to normal operation. He reduced the power to 33 inches of manifold pressure and set the propeller to 2,550 rpm. Shortly thereafter, the engine began losing power again, there was a second surge, then the propeller stopped. During an emergency landing, the pilot elected to cross over a road and land in an open field. He saw a power line along the road at the edge of the field and elected to cross under it to land. However, he did not see a single telephone pole on the opposite side of the road. The left wing struck the pole and the plane cartwheeled and crashed. Three occupants escaped with minor injuries and four others were uninjured. An investigation revealed that the crankshaft had failed from fatigue.

The crew was completing a positioning flight from Pueblo to Carlsbad on behalf of Air Resort Airlines. While cruising at an altitude of 11,700 feet over a mountainous area under VFR mode, weather conditions deteriorated. Shortly later, the airplane struck trees and crashed. Both pilots were seriously injured and the aircraft was destroyed.

Prior to flight the spark plugs on both engines were replaced due to minor engine vibration and the landing gear retract system wiring repaired due to the gear not retracting electrically on a prior occasion. After takeoff the gear would not retract electrically and the passenger had to crank up the gear manually. After the parachute jump the pilot shut down the left engine to isolate the vibration. He then started the left engine and feathered the right engine. Unable to unfeather the right engine he elected to land with full flaps and gear down after a straight-in approach. As he approached the threshold a Cessna 150 taxied onto the runway. The pilot executed a go-around while trying to retract the flaps and gear electrically without results. The passenger was attempting to retract the gear manually when the aircraft struck a tree. The pilot stated he did not make his landing intentions known on unicom during the approach. No pre-impact discrepancies were found to preclude normal prop operation. Normal elect power is halved with one generation inoperative.

The pilot took off with 4 passengers after waiting 4 hours for the air temperature to cool. The takeoff seemed normal, but over the river at about 50 feet agl, the aircraft began to sink. It impacted rough terrain on the far side of the river. The airport elevation was 2,045 feet msl and the temperature was 90 degrees. All five occupants were seriously injured.

Several black bears were spotted in a narrow canyon and the pilot began making tight, descending turns so his sightseeing passengers could get photographs. Reportedly, the stall warning horn came on, but the pilot continued the turns. He finally rolled out of the turn, but was headed uphill in the valley. The pilot was unable to maintain airspeed while climbing up the valley. Subsequently, the aircraft crashed and nosed over. The elevation of the crash site was about 3,000 feet and the reported temperature was 62° F. All six occupants were seriously injured.

Prior to the post-maintenance inspection flight the pilot/owner, who is a certificated a&p mechanic, had been calibrating the fuel flow on the right engine fuel injector pump. An external line had been connected to the fuel flow transmitter fitting of the fuel injector. Prior to the test flight the external line was removed and the fuel flow replaced. About 10 min after takeoff the pilot observed flames from 25 to 15 psi. The right engine was shut down and the prop feathered. After landing the pilot was unable to taxi the aircraft and the aircraft was abandoned.

The crew departed Shemya Airport at 0810LT on a short flight of 10 minutes to the Casco Grove Coast Guard Station (LORAN Station) based on Attu Island. At that time, weather conditions were considered as good with clouds down to 400 feet, broken at 2,000 feet, visibility eight miles and wind from 210 at 20 knots. Because of the short flight, the crew did not take the time to align the aircraft's inertial navigation system prior to departure. Upon arrival to Casco Grove Airport, weather deteriorated and the captain elected to maintain visual contact with the water surface while the copilot and the navigator were monitoring the approach on radar. On approach to the airport, the crew failed to realize their altitude was too low when the airplane struck the slope of a mountain located about 3 miles southwest of runway 02 threshold. The aircraft was destroyed and caught fire after impact. A crew member and one passenger were killed while 9 other occupants were injured.