United States of America

The pilot was conducting a scheduled air taxi flight with five passengers onboard. Shortly after departure, the pilot began to smell an electrical burn odor, and he elected to return to the airport. About 1 minute later, the electrical burn smell intensified, which was followed by visible smoke in the cockpit, and the pilot declared an emergency to the tower. After landing and all the passengers had safely departed the airplane, heavy smoke filled the cockpit and passenger compartment, and the pilot saw a candle-like flame just behind the pilot and co-pilot seats, just beneath the floorboards of the airplane. Moments later, the airplane was engulfed in flames. Postaccident examination of the airframe revealed the origin of the fire to be centered behind the pilot’s row of seats, where a wire harness was found improperly installed on top of the aft fuel line from the left tank. Examination of the wire harness found a range of thermal and electrical damage consistent with chafing from the fuel line. It is likely that the installation of the wire harness permitted contact with the fuel line, which resulted in chafing, arcing, and the subsequent fire.

While on final approach, the airplane gradually slowed to near its stall speed. About 600 ft beyond the last recorded data, the airplane impacted the ground in a nose-down attitude that was consistent with a stall. Postaccident examination revealed no preaccident mechanical failures or malfunctions that would have contributed to the accident. Witnesses near the accident site reported very heavy sleet with low visibility conditions, whereas a witness located near the final approach flightpath, about 2 miles before the accident site observed the airplane fly by below an overcast cloud layer with no precipitation present. Based on the witness accounts and weather data, the airplane likely entered a lake effect band of heavy sleet during the final portion of the flight. The airplane was modified with 5-bladed propellers, and other pilots reported it would decelerate rapidly, especially when the speed/propeller levers were moved to the high rpm (forward) position. The pilot usually flew a larger corporate jet and had not flown the accident airplane for 8 months. The passenger was a student pilot with an interest in becoming a professional pilot. The pilot’s poor airspeed control on final approach was likely influenced by a lack of recency in the turboprop airplane. The workload of inflight deicing tasks may have also contributed to the poor airspeed control. The aerodynamic effects of the heavy sleet that was encountered near the accident site likely contributed to the stall to some degree.

A pilot-rated witness observed the airplane during the final approach to the destination airport and stated that the airplane was flying slowly, with a high pitch attitude, and was “wallowing” as if nobody was flying. The airplane stalled and impacted the ground about 300 ft from the runway. GPS and automatic dependent surveillance-broadcast (ADS-B) data captured the accident flight, but the ADS-B data ended about 0.24 miles before the accident. GPS data showed that the airplane’s speed was at or near the published stall speed for the airplane’s given loading condition. The airplane sustained substantial damage to the fuselage and both wings. Examination of the airplane verified flight and engine control continuity. No preimpact anomalies were found with respect to the airplane, engines, or systems. The pilot allowed the airspeed to decrease during the approach, increased pitch attitude, and exceeded critical angle of attack, which resulted in an aerodynamic stall and spin into terrain.

The captain (who was the pilot flying) initiated the takeoff roll, and the airplane accelerated normally. According to the cockpit voice recorder (CVR) transcript, the first officer made the “V1” and then “rotate” callouts. According to the captain (in a postaccident interview), when he pulled back on the control column to rotate the airplane, “nothing happened,” and the control column felt like it “was in concrete” and “frozen.” The CVR captured that the first officer subsequently made the “V2” callout, then the captain said “come on” in a strained voice. Both pilots recalled in postaccident interviews that they both attempted to pull back on the controls, but the airplane did not rotate. The CVR captured that the first officer called out “abort.” The first officer pulled the thrust levers to idle and applied the brakes, and the captain deployed the thrust reversers. (See “Execution of Rejected Takeoff” for more information.) The airplane overran the departure end of the runway and continued through the airport perimeter fence and across a road, striking electrical distribution lines and trees before coming to rest in a pasture, where a postcrash fire ensued. The pilots, two additional crewmembers, and all passengers evacuated the airplane. Two passengers received serious injuries, and one received a minor injury. The airplane was totally destroyed by a post crash fire.

The pilot stated that the departure started normally but that, after becoming airborne, the airplane controls were not responding to his inputs as expected. The airplane continued to pitch up in a nose-high attitude and he was unable to push the control yoke forward, which he described as feeling like he was “stretching” cables with forward pressure. With the airplane’s pitch uncontrollable, he elected to make a rapid maneuver toward an unpopulated area. The airplane descended into trees; after coming to a stop, a fire erupted. A postaccident examination of the flight control system revealed no definitive evidence of preimpact mechanical malfunctions or failures. Because the elevator system was extensively damaged and was partially consumed by fire, the investigation was not able to determine the cause of the pitch control anomaly. The airplane’s weight and center of gravity (CG) could not be confirmed. The burned remains of items found in the airplane could not be identified and the location of those items at impact could not be confirmed.

The pilot was on a cross-country flight, receiving vectors for an instrument approach while in instrument meteorological conditions (IMC). The approach controller instructed the pilot to descend to 2,800 ft mean sea level (msl) until established on the localizer, and subsequently cleared the flight for the instrument landing system (ILS) approach to runway 28R, then circle to land on runway 23. About 1 minute later, the controller told the pilot that it looked like the airplane was drifting right of course and asked him if he was correcting back on course. The pilot responded “correcting, 22G.” About 9 seconds later, the pilot transmitted “SoCal, is 22G, VFR runway 23” to which the controller told the pilot that the airplane was not tracking on the localizer and subsequently canceled the approach clearance and instructed the pilot to climb and maintain 3,000 ft. As the pilot acknowledged the altitude assignment, the controller issued a low altitude alert, and provided the minimum vectoring altitude in the area. The pilot acknowledged the controller’s instructions shortly after. At this time, recorded advanced dependent surveillance-broadcast (ADS-B) data showed the airplane on a northwesterly heading at an altitude of 2,400 ft msl. Over the course of the following 2 minutes, the controller issued multiple instructions for the pilot to climb to 4,000 ft, which the pilot acknowledged; however, ADS-B data showed that the airplane remained between 2,500 ft and 3,500 ft. The controller queried the pilot about his altitude and the pilot responded, “2,500 ft, 22G.” The controller subsequently issued a low altitude alert and advised the pilot to expedite the climb to 5,000 ft. No further communication was received from the pilot despite multiple queries from the controller. ADS-B data showed that the airplane had begun to climb and reached a maximum altitude of 3,500 ft before it began a descending right turn. The airplane remained in the right descending turn at a descent rate of about 5,000 ft per minute until the last recorded target at 900 ft msl, located about 1,333 ft northwest of the accident site. The airplane and two houses were destroyed. The pilot and the driver of a UPS truck were killed. Two other people on the ground were injured.

The captain and first officer were assigned a two-leg overnight on-demand cargo flight. The flight crew were accustomed to flying night cargo flights, had regularly flown together, and were experienced pilots. The first leg of the trip was uneventful and was flown by the captain; however, their trip was delayed 2 hours and 20 minutes at the intermediate stop due to a delay in the freight arriving. The flight subsequently departed with the first officer as the pilot flying. While enroute, about forty minutes from the destination, the flight crew asked the air traffic controller about the NOTAMs for the instrument landing system (ILS) instrument approach procedure at the destination. The controller informed the flight crew of two NOTAMs: the first pertained to the ILS glidepath being unserviceable and the second applied to the localizer being unserviceable. When the controller read the first NOTAM, he stated he did not know what “GP” meant, which was the abbreviation for the glideslope/glidepath on the approach. The controller also informed the flight crew that the localizer NOTAM was not in effect until later in the morning after their expected arrival, which was consistent with the published NOTAM. The flight crew subsequently requested the ILS approach and when the flight was about 15 miles from the final approach fix, the controller cleared the flight for the ILS or localizer approach, to which the captain read back that they were cleared for the ILS approach. As the flight neared the final approach fix, the captain reported that they had the airport in sight; he cancelled the instrument flight rules flight plan, and the flight continued flying towards the runway. The airplane crossed the final approach fix off course, high, and fast. The cockpit voice recorder (CVR) transcript revealed that the captain repeatedly instructed the first officer to correct for the approach path deviations. Furthermore, the majority of the approach was conducted with a flight-idle power setting and no standard altitude callouts were made during the final approach. Instead of performing a go-around and acknowledging the unstable approach conditions, the captain instructed the first officer to use the air brakes on final approach to reduce the altitude and airspeed. Shortly after this comment was made, the captain announced that they were low on the approach and a few seconds later the captain announced that trees were observed in their flight path. The CVR captured sounds consistent with power increasing; however, the audible stall warning tone was also heard. Subsequently, the airplane continued its descent and impacted terrain about .70 nautical mile from the runway. The airplane was destroyed by impact forces and both occupants were killed.

The company pilot and two employees had departed on an aerial imagery survey flight of forest vegetation. The airplane began to level off at an altitude of about 16,100 ft mean sea level (msl) and accelerated to a maximum recorded groundspeed of 209 knots. Less than 2 minutes later, the groundspeed decreased to about 93 knots, and the airplane descended about 500 ft while on a steady heading. The airplane subsequently entered a rapid descent and a right turn, and “mayday, mayday, mayday” and “we’re in a spin” transmissions were broadcast to air traffic control (ATC). A witness, who was located near the accident site, noticed the airplane nose down at high rate of speed and then saw the airplane spinning rapidly about its longitudinal axis. The airplane wreckage was located in remote wetlands and wooded terrain. Postaccident examination revealed that the airplane impacted the ground in a nose-low vertical attitude and at high speed. All major components of the airplane were located at the accident site. Examination of the airframe, engines, and propellers revealed no preimpact mechanical malfunctions or failures that would have precluded normal operation. According to the aircraft performance study for this accident, when the airplane pitched down, the normal load factor decreased rapidly from about 1.6 to less than 1 G. A rapid decrease in normal load factor is consistent with a stall when the wing exceeds its critical angle of attack. At that point, the air flow becomes separated at the wing, and the wing can no longer generate the necessary lift. If the airplane is in uncoordinated flight at the stall, a spin can result. Thus, the pilot likely did not maintain adequate airspeed, causing the airplane to exceed its critical angle of attack and enter a stall and spin. An important but unknown factor before and during the initial stall was the behavior of the pilot regarding his flight control inputs, including his possible attempt to recover. The airplane’s Pilot Operating Handbook states that spins are not authorized and does not include a procedure for inadvertent spin recovery.

The pilot was transporting six passengers on a scheduled revenue flight in instrument meteorological conditions. The pilot familiarized himself with the weather conditions before departure and surmised that he would be executing the instrument landing system (ILS) instrument approach for the landing runway at the destination airport. The operator prohibited approaches to runways less than 4,000 ft long if the tailwind component was 5 knots or more. The landing runway was 498 ft shorter than the operator-specified length. The pilot said he obtained the automated weather observing system (AWOS) data at least twice during the flight since he was required to obtain it before starting the instrument approach and then once again before he crossed the approach’s final-approach-fix (FAF). Though the pilot could not recall when he checked the AWOS, he said the conditions were within the airplane and company performance limits and he continued with the approach. A review of the wind data at the time he accepted the approach revealed the tailwind component was within limitations. As the airplane approached the FAF, wind speed increased, and the tailwind component ranged between 1 and 7 knots. Since the exact time the pilot checked the AWOS is unknown, it is possible that he obtained an observation when the tailwind component was within operator limits; however, between the time that the airplane crossed over the FAF and the time it landed, the tailwind component increased above 5 knots. The pilot said the approach was normal until he encountered a strong downdraft when the airplane was about 50 to 100 ft above the ground. He said that the approach became unstabilized and that he immediately executed a go-around; the airplane touched down briefly before becoming airborne again. The pilot said he was unable to establish a positive rate of climb and the airplane impacted trees off the end of the runway. The accident was captured on three airport surveillance cameras. A study of the video data revealed the airplane made a normal landing and touched down about 500 ft from the beginning of the runway. It was raining heavily at the time. The airplane rolled down the runway for about 21 seconds, and then took off again. The airplane entered a shallow climb, collided with trees, and caught on fire. All seven occupants were seriously injured and the airplane was destroyed.

The flight crew was conducting a personal flight with two passengers onboard. Before departure, the cockpit voice recorder (CVR) captured the pilots verbalizing items from the before takeoff checklist, but there was no challenge response for the taxi, before takeoff, or takeoff checklists. Further, no crew briefing was performed and neither pilot mentioned releasing the parking brake. The left seat pilot, who was the pilot flying (PF) and pilot-in-command (PIC), initiated takeoff from the slightly upsloping 3,665-ft-long asphalt runway. According to takeoff performance data that day and takeoff performance models, the airplane had adequate performance capability to take off from that runway. Flight data recorder (FDR) data indicated each thrust lever angle was set and remained at 65° while the engines were set and remained at 91% N1. During the takeoff roll, the CVR recorded the copilot, who was the pilot monitoring (PM) and second-in-command (SIC), making callouts for “airspeed’s alive,” “eighty knots cross check,” “v one,” and “rotate.” A comparison of FDR data from the accident flight with the previous two takeoffs showed that the airplane did not become airborne at the usual location along the runway, and the longitudinal acceleration was about 33% less. At the time of the rotate callout, the airspeed was about 104 knots calibrated airspeed, and the elevator was about +9° airplane nose up (ANU). Three seconds after the rotate callout, the CVR recorded the sound of physical straining, suggesting the pilot was likely attempting to rotate the airplane by pulling the control yoke. The CVR also captured statements from both the copilot and pilot expressing surprise that the airplane was not rotating as they expected. CVR and FDR data indicated that between the time of the rotate callout and the airplane reaching the end of the airport terrain, the airspeed increased to about 120 knots, the weight-on-wheels (WOW) remained in an on-ground state, and the elevator position increased to a maximum value of about +16° ANU. However, the airplane’s pitch attitude minimally changed. After the airplane cleared the end of the airport terrain where the ground elevation decreased 20 to 25 ft, FDR data indicate that the WOW transitioned to air mode with near-full ANU elevator control input, and the airplane pitched up nearly 22° in less than 2 seconds. FDR data depicted forward elevator control input in response to the rapid pitch-up, and the CVR recorded a stall warning then stick shaker activation. An off airport witness reported seeing the front portion of the right engine impact a nearby pole past the departure end of the runway. The airplane then rolled right to an inverted attitude, impacted the ground, then impacted an off airport occupied building. The airplane was destroyed by impact forces and a post crash fire and all four occupants were killed. On ground, four other people were injured, one seriously.