Bethel

About 0800, the commercial pilot did a preflight inspection of the accident airplane, in preparation for a cargo flight. Dark night, visual meteorological conditions prevailed. He indicated that the weather conditions were clear and cold, and frost was on the airplane. He said the frost was not bonded to the skin of the airplane, and he was able to use a broom to clean off the frost, resulting in a clean wing and tail surface. He reported that no deicing fluid was applied. After takeoff, he retracted the flaps to about 5 degrees at 110 knots of airspeed. The airplane then rolled to the right about three times in a manner he described as a wave, or vortex-like movement. He applied left aileron and lowered the flaps to 20 degrees, but the roll to the right was more severe. The pilot said the engine power was "good." He then noticed that the airplane was descending toward the ground, so he attempted to put the flaps completely down. His next memory was being outside the airplane after it collided with the ground. The airplane's information manual contains several pages of limitations and warnings about departing with even small amounts of frost, ice, snow, or slush on the airplane, as it adversely affects the airplane's flight characteristics. The manufacturer requires a visual or tactile inspection of the wings, and horizontal stabilizer to ensure they are free of ice or frost if the outside air temperature is below 10 degrees C, (50 degrees F), and notes that a heated hangar or approved deicing fluids should be used to remove ice, snow and frost accumulations. The weather conditions included clear skies, and a temperature of -11 degrees F. Post accident examination of the airplane revealed no observed mechanical malfunction. An examination of the engine revealed internal over-temperature damage, and minor external fire damage consistent with a massive spike of fuel flow at the time of ground impact. Damage to the propeller blades was consistent with high power at the time of ground impact. The rolling/vortex motion of the airplane was consistent with airframe contamination due to frost.

The commercial certificated pilot was attempting to land on a remote runway during a Title 14, CFR Part 135, cargo flight. The approach end of the runway is located at the edge of a river. During the pilot's fourth attempt to land, the airplane collided with the river embankment, and sustained structural damage. The director of operations for the operator reported that he interviewed several witnesses to the accident. They told him that the weather conditions in the area had been good VFR, but as the pilot was attempting to land, rain and mist moved over the area, reducing the visibility to about 1/4 mile. Within 30 minutes of the accident, the weather conditions were once again VFR. The pilot told an FAA inspector that the weather conditions consisted of a 500 foot ceiling and 2 miles of visibility. The pilot reported that he made 3 passes over the runway before attempting to land. On the last landing approach, while maintaining 80 knots airspeed, the pilot said the nose of the airplane dropped, he applied full power and tried to raise the nose, but the airplane collided with the river bank.

The commercial pilot was positioning the airplane from the departure airport to another airport. The flight took place on a dark night with overcast skies, and no discernible horizon. The pilot departed and climbed to a cruise altitude between 1,200 and 1,400 feet msl. About 4 miles south of the departure airport, the airplane collided with an east-west ridge at 1,200 feet msl. The ridgeline is perpendicular to the direct route of flight between the departure and destination airports, and rises from west to east with a summit elevation of 1,714 feet msl. The departure airport was a newly commissioned airport 3 miles east-northeast of the old airport. The accident flight was the pilot's second trip to the new airport, and his first night departure from either the old or new airport. Direct flight from the new airport to the destination airport requires a higher altitude to clear the ridgeline than does a direct flight from the old airport. A direct flight from the old airport crosses the same ridgeline farther to the west, where the elevation of the ridge is less than 500 feet msl.

The captain and first officer were conducting a localizer DME back course approach to runway 36 in a twin-engine turboprop airplane during a night cargo flight under IFR conditions. The minimum visibility for the approach was one mile, and the minimum descent altitude (MDA) was 460 feet msl (338 feet agl). Prior to leaving their cruise altitude, the first officer listened to the ATIS information which included an altimeter setting of 29.30 inHg. No other altimeter information was received until the crew reported they were inbound on the approach. At that time, tower personnel told the crew that the visibility was one mile in light snow, the wind was from 040 degrees at 22 knots, and the altimeter setting was 29.22 inHg. The crew did not reset the airplane altimeters from 29.30 to 29.22. At the final approach fix (5 miles from the runway), the captain began a descent to the MDA. Thirty-six seconds before impact, the first officer cautioned the captain about the airplane's high airspeed. Due to strong crosswinds, the captain disconnected the autopilot 22 seconds before impact. He said he pushed the altitude hold feature on the flight director at the MDA. Eighteen seconds before impact, the airplane leveled off about 471 feet indicated altitude, but then descended again 9 seconds later. The descent continued until the airplane collided with the ground, 3.5 miles from the runway. The crew said that neither the airport, or the snow-covered terrain, was observed before impact. The crew reported that the landing lights were off. The airplane was not equipped with a ground proximity warning system.

The certificated commercial pilot, with five passengers aboard, was departing runway 18 on a scheduled commuter flight. The pilot stated that the flight's original departure time was delayed for two hours due to ice fog, and low visibility. He said that just after takeoff, the engine surged followed by a loss of power. The airplane collided with snow-covered terrain during an off-airport emergency landing, and sustained substantial damage to the propeller, fuselage, and wings. Following retrieval of the airplane, an FAA airworthiness inspector examined the airplane, and found no mechanical anomalies. While still attached to the airplane, the engine was started and run at idle. The engine later produced full power on an engine test stand. A pilot-rated Alaska State Trooper, with extensive experience in the accident airplane make and model, examined the airplane soon after the accident. He said the wings, horizontal stabilizer, and elevators had an accumulation of frost.

The airline transport pilot departed on a CFR Part 135 scheduled passenger flight to a remote coastal village. When the flight did not return, an aerial search was initiated. The wreckage was located the following day along the pilot's intended route, about 49 miles from the departure airport. The airplane had collided with flat, featureless, snow-covered, terrain. A pilot that departed about one minute after the accident airplane's departure, had a similar route of flight. He characterized the weather conditions along the accident airplane's route as overcast, with ceilings ranging between 2,500 and 4,500 feet. He said that as he approached the area of the accident, he encountered 'a wall of weather' starting from the ground, with tops at 1,500 feet. He added that visibility was low, with fog and varied layers of cloud cover. The pilot stated that he changed his route in order to avoid the worsening weather conditions. He added that with satisfactory weather conditions, and given the intended destination of the accident airplane, the standard route of flight would be directly over the location of the accident site. No pre accident anomalies were noted with the accident airplane.

The pilot of Cessna 207A, N800GA, was returning to his company base, passing about 2 miles north of a remote airstrip that was along the route of flight. The airstrip did not have any control tower. [Communications around an uncontrolled airport are conducted on a common traffic advisory frequency (CTAF)]. The pilot of a Short SC7, N451SA, announced his departure from the same airstrip on the CTAF, and took off in a northerly direction. He then began a climbing right turn toward the same destination as the Cessna 207A was proceeding. The two airplanes collided in mid-air, about 1.49 nautical miles east-northeast of the airstrip, which was about 18.3 miles west of their destination. They were observed spiraling downward from about 800 ft above the ground. Both airplanes were found lying flat and upright on a frozen lake, entangled together at the accident site. The Cessna's burned wreckage was lying on top of (and positioned toward the aft third of) the burned wreckage of the Short SC7.

The pilot of Cessna 207A, N800GA, was returning to his company base, passing about 2 miles north of a remote airstrip that was along the route of flight. The airstrip did not have any control tower. [Communications around an uncontrolled airport are conducted on a common traffic advisory frequency (CTAF)]. The pilot of a Short SC7, N451SA, announced his departure from the same airstrip on the CTAF, and took off in a northerly direction. He then began a climbing right turn toward the same destination as the Cessna 207A was proceeding. The two airplanes collided in mid-air, about 1.49 nautical miles east-northeast of the airstrip, which was about 18.3 miles west of their destination. They were observed spiraling downward from about 800 ft above the ground. Both airplanes were found lying flat and upright on a frozen lake, entangled together at the accident site. The Cessna's burned wreckage was lying on top of (and positioned toward the aft third of) the burned wreckage of the Short SC7.

The pilot was departing on a cargo flight. Just after takeoff, a company dispatcher attempted to contact the pilot by radio. The pilot replied, 'stand by.' No further communication was received from the pilot. The airplane was observed by ATC personnel in a left turn back toward the airport at an estimated altitude of 200 feet above the ground. The angle of bank during the turn increased, and the nose of the airplane suddenly dropped toward the ground. The airplane struck the ground in a nose and left wing low attitude about 1 mile west of the airport. The terrain around the airport was relatively flat, snow covered tundra. The airplane was destroyed. A postaccident examination of the engine did not reveal any mechanical malfunction. Power signatures in the engine indicated it was developing power. A postaccident examination of the propeller assembly revealed one of three composite blades had rotated in its blade clamp 17/32 inch; however, the propeller manufacturer indicated blade contact with the ground would try to drive the propeller from a high blade angle toward a low blade angle. Movement toward a low blade angle would compress the propeller feathering springs, while movement toward a high blade angle would result in a hydraulic lock condition as oil in the system is compressed. The propeller manufacturer indicated they had no reports of composite blade slippage in the blade clamps.

After receiving a special VFR (SVFR) clearance, the pilot departed the airport with a passenger on a scheduled commuter flight to a remote airport. About 14 miles north of the airport, at 1,000 feet mean sea level (msl), the pilot encountered whiteout conditions and reversed course, descending to about 500 feet msl. The pilot requested a SVFR arrival back to the departure airport and began maneuvering to intercept the inbound course. While in instrument meteorological conditions, the airplane descended and collided with flat, snow covered terrain about 5 mile north of the airport. The pilot was unable to distinguish any terrain features until impact with the ground.