Positioning

For unknown reasons, the aircraft completed a belly landing at Panana City-Tocument Airport. Both occupants evacuated safely and the aircraft was damaged beyond repair.

The accident flight was a repositioning flight being operated by two airline transport pilots, and it was the multiengine turboprop airplane's first flight after an aviation maintenance technician (AMT) had replaced the left engine propeller with an overhauled propeller. The AMT subsequently performed an engine run, which included verifying correct power settings and corresponding blade angles. A review of flight data recorder (FDR) data revealed that, about 2 seconds after rotation, the left engine propeller rpm decreased to 60 percent, and the left engine torque increased off-scale (beyond 5,000 ft lbs), which is consistent with the left propeller traveling to the feathered position and the engine torque increasing in an attempt to maintain propeller rpm. About 30 seconds later, the flight crew shut down the left engine and attempted to return to the departure airport. Postaccident examination of the rudder trim actuator revealed that the rudder trim was at its full-right limit, which would have occurred to counteract the left engine drag before its shutdown. Based on this evidence, it is likely that the flight crew did not readjust the trim when the drag was alleviated, which resulted in the airplane being operated in a crosscontrolled attitude for about 50 seconds with a left bank and full-right rudder trim. Although the airplane should have been able to climb about 500 ft per minute with one engine operating, it slowed and descended from 300 ft in the cross-controlled attitude until it stalled, as indicated by a stall warning recorded by the cockpit voice recorder, and subsequently impacted terrain. Examination of the wreckage, including teardown examination of the left engine and propeller, did not reveal any preimpact mechanical anomalies. Review of the airplane maintenance manual revealed instructions to check the propeller reversing linkage on the front end of the engine, which controlled the beta valve, for proper rigging during propeller installation. The manual also contained a warning that misadjustment of the beta valve can cause unplanned feathering of the propeller and result in a possible hazard to airplane operation and over torque damage to the engine; however, the beta valve rigging could not be verified postaccident due to impact damage. Additionally, the ground/flight idle solenoid energizes when weight becomes off wheels and further opens the beta valve, which could exacerbate an existing misrigged condition as soon as the airplane becomes airborne, which is when the airplane experienced the uncommanded propeller feathering. The FDR data were consistent with the flight crew not performing the Before Takeoff (Runup) checklist. One of the items on that checklist was a low-pitch solenoid test, which would have energized the solenoid and possibly driven the left propeller uncommanded to feather during ground operations rather than in flight. A similar test during the post maintenance engine-run would have had the same results.

The pilot was conducting an early morning repositioning flight of the cargo airplane. Shortly after takeoff, the pilot reported to air traffic control that he had “lost an engine” and would return to the airport. Several witnesses reported that the engines were running rough and one witness reported that he did not hear any engine sounds just before the impact. The airplane impacted trees, a wooden enclosure, a chain-linked fence, and shrubs in a residential area and was damaged by the impact and postimpact fire. The airplane had been parked outside for 5 days before the accident flight and had been plugged in to engine heaters the night before the flight. It was dark and snowing lightly at the time of the accident. The operator reported that no deicing services were provided before the flight and that the pilot mechanically removed all of the snow and ice accumulation. The wreckage and witness statements were consistent with the airplane being in a right-winglow descent but the airplane did not appear to be out of control. Neither of the propellers were at or near the feathered position. The emergency procedures published by the manufacturer for a loss of engine power stated that pilots should first secure the engine and feather the propeller following a loss of engine power and then turn the fuel selector for that engine to “off.” The procedures also cautioned that continued flight might not be possible if the propeller was not feathered. The right fuel selector valve and panel were found in the off position. Investigators were not able to determine why an experienced pilot did not follow the emergency procedures and immediately secure the engine following the loss of engine power. It is not known how much snow and ice had accumulated on the airplane leading up to the accident flight or if the pilot was successful in removing all of the snow and ice with only mechanical means. The on-scene examination of the wreckage and the teardown of both engines did not reveal any preimpact mechanical malfunctions or failures. While possible, it could not be determined if water or ice ingestion lead to the loss of engine power at takeoff.

The airline transport pilot was conducting a cross-country repositioning flight. While en route to the destination airport, the pilot contacted air traffic control and stated that he was beginning to descend. No further radio transmissions were made by the pilot. Radar and GPS information showed, about the same time as the pilot's last transmission, the airplane's flightpath began descending in a westerly direction. The last recorded GPS point showed the airplane about 200 ft southwest of the initial impact point, 90 ft above ground level, and at a groundspeed of 66 knots. The airplane wreckage was located in an open field and impact signatures were consistent with a stall/spin, which had resulted in a near-vertical impact at a slow airspeed. The right propeller blades were found in the feathered position. Examination of the right engine found that the oil gauge housing extension was improperly secured to the oil gauge housing, which resulted in a loss of engine oil. Additionally, the examination revealed a hole in the right engine's crankcase, metal material in the oil sump, and signatures consistent with the lack of lubrication. Cockpit switches were positioned in accordance with the in-flight shutdown of the right engine. No anomalies were found with the left engine or airframe that would have precluded normal operation. Another pilot who had flown with the accident pilot reported that the pilot typically used the autopilot, and the autopilot system was found with the roll, heading, and pitch modes active. During the descent, no significant changes of heading were recorded, and the direction of travel before the stall was not optimal for the airplane to land before a fence line. It is likely that the autopilot was controlling the airplane's flightpath before the stall. Despite one operating engine, the pilot did not maintain adequate airspeed and exceeded the airplane's critical angle-of-attack (AOA), which resulted in an aerodynamic stall/spin. Correcting the last GPS recorded airspeed for prevailing wind, the airplane's indicated airspeed would have been about 72 knots, which is above the airplane's 0-bank stall speed, but an undetermined mount of bank would have been applied to maintain heading, which would have accelerated the stall speed. It could not be determined why the pilot did not maintain adequate airspeed or notify air traffic controller of an engine problem. Although a review of the pilot's medical records revealed that he had several historical medical conditions and the toxicology tests detected several sedating allergy medications in his system, it was inconclusive whether the medical conditions or medications impaired the pilot's ability to fly the airplane or if the pilot was incapacitated. It is also possible that the pilot was distracted by the loss of oil from the right engine and that this resulted in his failure to maintain adequate airspeed, his exceedance of the airplane's critical AOA, and a subsequent stall/spin; however, based on the available evidence, the investigation could not determine the reason for the pilot's lack of corrective actions.

The pilots of the very light jet were conducting a positioning flight in instrument meteorological conditions. The flight was cleared by air traffic control for the instrument landing system (ILS) approach; upon being cleared for landing, the tower controller reported to the crew that there was no standing water on the runway. Review of the airplane's flight data recorder (FDR) data revealed that the airplane reached 50 ft above touchdown zone elevation (TDZE) at an indicated airspeed of 118 knots (KIAS). The airplane crossed the runway displaced threshold about 112 KIAS, and it touched down on the runway at 104 KIAS with about a 7-knot tailwind. FDR data revealed that, about 1.6 seconds after touchdown of the main landing gear, the nose landing gear touched down and the pilot's brake pedal input increased, with intermediate oscillations, over a period of 7.5 seconds before reaching full pedal deflection. During this time, the airplane achieved its maximum wheel braking friction coefficient and deceleration. The cockpit voice recorder recorded both pilots express concern the that the airplane was not slowing. About 4 seconds after the airplane reached maximum deceleration, the pilot applied the emergency parking brake (EPB). Upon application of the EPB, the wheel speed dropped to zero and the airplane began to skid, which resulted in reverted-rubber hydroplaning, further decreasing the airplane's stopping performance. The airplane continued past the end of the runway, crossed a service road, and came to rest in a drainage ditch. Postaccident examination of the brake system and data downloaded from the brake control unit indicated that it functioned as commanded during the landing. The airplane was not equipped with thrust reversers or spoilers to aid in deceleration. The operator's standard operating procedures required pilots to conduct a go-around if the airspeed at 50 ft above TDZE exceeded 111 kts. Further, the landing distances published in the airplane flight manual (AFM) are based on the airplane slowing to its reference speed (Vref) of 101 KIAS at 50 ft over the runway threshold. The airplane's speed at that time exceeded Vref, which resulted in an increased runway distance required to stop; however, landing distance calculations performed in accordance with the AFM showed that the airplane should still have been able to stop on the available runway. An airplane performance study also showed that the airplane had adequate distance available on which to stop had the pilot continued to apply maximum braking rather than engage the EPB. The application of the EPB resulted in skidding, which increased the stopping distance. Although the runway was not contaminated with standing water at the time of the accident, the performance study revealed that the maximum wheel braking friction coefficient was significantly less than the values derived from the unfactored wet runway landing distances published in the AFM, and was more consistent with the AFM-provided landing distances for runways contaminated with standing water. Federal Aviation Administration Safety Alert for Operators (SAFO) 15009 warns operators that, "the advisory data for wet runway landings may not provide a safe stopping margin under all conditions" and advised them to assume "a braking action of medium or fair when computing time-of-arrival landing performance or [increase] the factor applied to the wet runway time-of-arrival landing performance data." It is likely that, based on the landing data in the AFM, the crew expected a faster rate of deceleration upon application of maximum braking; when that rate of deceleration was not achieved, the pilot chose to engage the EPB, which only further degraded the airplane's braking performance.

The crew departed Laguna de Tres Palos on a positioning flight to the Acapulco-General Juan N. Álvarez International Airport. During the takeoff procedure, the seaplane started to oscillate from left to right. At a speed of about 45 knots, the crew abandoned the takeoff procedure when the aircraft nosed down, plunged into water and came to rest, inverted and submerged. Both pilots evacuated safely while the aircraft was damaged beyond repair.

The twin engine aircraft departed Moscow-Vnukovo Airport on a positioning flight to Makhatchkala, carrying a crew of three. On approach to Makhatchkala Airport, the crew was unable to lower the gear that remained stuck in their wheel well. Despite several attempts, the crew was unable to lower the gear manually and eventually decided to return to Moscow-Vnukovo for an emergency landing. The aircraft belly landed on a foam covered runway and slid for few dozen metres before coming to rest. All three crew members escaped uninjured and the aircraft was damaged beyond repair.

The crew departed Lanseria on a positioning flight to Lubumbashi where the aircraft was based. En route, the crew encountered engine problems and elected to make an emergency landing on the Lusaka - Chirundu Road. Eventually, the twin engine aircraft crashed in a cliff. Both occupants were injured and the aircraft was destroyed.

The airline transport pilot was repositioning the airplane to an airport near the owner's summer home. The airplane was not maintained for instrument flight, and the pilot had diverted the day before the accident due to weather. On the day of the accident, the pilot departed for the destination, but returned shortly after due to weather. After waiting for the weather conditions to improve, the pilot departed again that afternoon, and refueled the airplane at an intermediate airport before continuing toward the destination. The route of flight followed a highway that traversed a mountain pass. A witness located along the highway stated that he saw the accident airplane traveling northbound toward the mountain pass, below the overcast cloud layer. He also stated that the mountain pass was obscured, and he could see a thunderstorm developing toward the west, which was moving east toward the pass. A second witness, located near the accident site, saw the airplane descend vertically from the base of the clouds while spinning in a level attitude and impact the ground. The second witness reported that it was snowing and that the visibility was about ¼ mile at the time of the accident. The airplane impacted terrain in a level attitude, and was consumed by a postcrash fire. Examination of the flight controls, airframe, and engine revealed no mechanical malfunctions or anomalies that would have precluded normal operation. It is likely that the pilot experienced spatial disorientation and a subsequent loss of aircraft control upon encountering instrument meteorological conditions. The airplane exceeded its critical angle of attack and entered a flat spin at low altitude, resulting in an uncontrolled descent and impact with terrain.

The crew departed Moscow-Sheremetyevo Airport on a positioning flight to Moscow-Vnukovo Airport. On approach by night, the crew configured the aircraft for landed when he realized that the right main gear remained stuck in its wheel well. The crew following a holding pattern and after the runway was covered with foam, he completed an emergency landing. After touchdown, the right wing contacted ground and the aircraft slid for few dozen metres before coming to rest. Both pilots escaped uninjured and the aircraft was damaged beyond repair.