Texas

The instrument-rated commercial pilot was approaching the destination airport after a cross country flight in night instrument meteorological conditions. According to radar track data and air traffic control communications, while receiving radar vectors to the final approach course, the pilot did not always immediately comply with assigned headings and, on several occasions, allowed the airplane to descend below assigned altitudes. According to airplane performance calculations based on radar track and GPS data, the pilot made an engine power reduction about 2.5 minutes before the accident as he maneuvered toward the final approach fix. Following the engine power reduction, the airplane's airspeed decreased from 162 to 75 knots calibrated airspeed, and the angle of attack increased from 2.7° to 14°. About 4 miles from the final approach fix, the airplane descended below the specified minimum altitude for that segment of the instrument approach. The tower controller subsequently alerted the pilot of the airplane's low altitude, and the pilot replied that he would climb. At the time of the altitude alert, the airplane was 500 ft below the specified minimum altitude of 2,000 ft mean sea level. According to airplane performance calculations, 5 seconds after the tower controller told the pilot to check his altitude, the pilot made an abrupt elevator-up input that further decreased airspeed, and the airplane entered an aerodynamic stall. A witness saw the airplane abruptly transition from a straight-and-level flight attitude to a nose-down, steep left bank, vertical descent toward the ground, consistent with the stall. Additionally, a review of security camera footage established that the airplane had transitioned from a wings-level descent to a near vertical spiraling descent. A post accident examination of the airplane did not reveal any anomalies that would have precluded normal operation during the accident flight. Although the pilot had monocular vision following a childhood injury that resulted in very limited vision in his left eye, he had passed a medical flight test and received a Statement of Demonstrated Ability. The pilot had flown for several decades with monocular vision and, as such, his lack of binocular depth perception likely did not impede his ability to monitor the cockpit instrumentation during the accident flight. The pilot had recently purchased the airplane, and records indicated that he had obtained make and model specific training about 1 month before the accident and had flown the airplane about 10 hours before the accident flight. The pilot's instrument proficiency and night currency could not be determined from the available records; therefore, it could not be determined whether a lack of recent instrument or night experience contributed to the pilot's difficulty in maintaining control of the airplane.

The instrument-rated private pilot was conducting a personal cross-country flight in the airplane. A review of the air traffic control transcripts and radar data revealed that the pilot was executing the RNAV GPS Y instrument approach to the runway. The air traffic controller then canceled the pilot's approach clearance and issued a heading change off of the approach course to provide spacing between a preceding aircraft. The pilot acknowledged the heading assignment. Radar data indicated that, after the controller cancelled the approach, the airplane began a left climbing turn from 5,600 to 5,800 ft, continued the left turn through the assigned 270 heading, and then descended rapidly. At that point, the airplane was no longer visible on the controller's radar display, and contact with the pilot was lost. The final recorded radar return showed the airplane at 5,100 ft. The airplane impacted a television tower guy wire, several power lines, and terrain, and then came to rest in an open field about 800 ft from the tower. A postaccident examination of the airplane and engine revealed no anomalies that would have precluded normal operation. A postaccident examination of the engine revealed rotational signatures on the first stage compressor blades and light rotational signatures in the compressor and power turbines, and debris was found in the engine's gas path, all of which are consistent with engine rotation at impact. A witness in the parking lot next to the television tower stated that he heard the accident airplane overhead, saw a large flash of light that filled his field of view, and then observed the television tower collapse on top of itself. Surveillance videos located 1.5 miles north-northeast and 0.3 mile north-northwest of the accident site showed the airplane in a left descending turn near the television tower. After it passed the television tower, multiple bright flashes of light were observed, which were consistent with the airplane impacting the television tower guy wire and then the power lines. Further, the radar track and accident wreckage were consistent with a rapid, descending left turn to impact. Weather conditions were conducive to the accumulation of ice at the destination airport about the time that the pilot initiated the left turn. It is likely that the airplane accumulated at least light structural icing during the descent and that this affected the airplane's controllability. Also, the airplane likely encountered wind gusting up to 31 knots as it was turning; this also could have affected the airplane's controllability. The night, instrument meteorological conditions at the time of the accident were conducive to the development of spatial disorientation, and the airplane's rapid, descending left turn to impact is consistent with the pilot's loss of airplane control due to spatial disorientation. Therefore, based on the available evidence, it is likely that, while initiating the climbing left turn, the pilot became spatially disoriented, which resulted in his loss of airplane control and his failure to see and avoid the tower guy wire, and that light ice accumulation on the airplane and the gusting wind negatively affected the airplane's controllability.

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.

Witnesses reported observing the airplane flying slowly toward the airport at a low altitude. The left engine was at a low rpm; "sputtering," "knocking," or making a "banging" noise; and trailing black smoke. One witness said that, as the airplane passed over his location, he saw the tail "kick" horizontally to the right and the airplane bank slightly left. The airplane subsequently collided with trees and impacted a field 1/2 mile north of the airport. Disassembly of the right engine revealed no anomalies, and signatures on the right propeller blades were consistent with power and rotation on impact. The left propeller was found feathered. Disassembly of the left engine revealed that the spark plugs were black and heavily carbonized, consistent with a rich fuel-air mixture; the exhaust tubing also exhibited dark sooting. The rubber boot that connected the intercooler to the fuel injector servo was found dislodged and partially sucked in toward the servo. The clamp used to secure the hose was loose but remained around the servo, the safety wire on the clamp was in place, and the clamp was not impact damaged or bent. The condition of the boot and the clamp were consistent with improper installation. The time since the last overhaul of the left engine was about 1,050 hours. The last 100-hour inspection occurred 3 months before the accident, and the airplane had been flown only 0.8 hour since then. It could not be determined when the rubber boot was improperly installed. Although the left engine had failed, the pilot should have been able to fly the airplane and maintain altitude on the operable right engine, particularly since he had appropriately feathered the left engine.

The twin engine aircraft, owned by Lawrence R. Liptack, crashed in flames in an open field located northeast of Bowie, Texas. The pilot and owner, aged 51, was killed with his son aged 10. The multi-engine airplane was about 500 ft above ground level (agl) and on a left base landing approach when a witness saw the airplane suddenly point straight down, begin spinning, and make three complete rotations before impacting terrain in a partially nose-down attitude. The airplane came to rest upright, and was mostly consumed by an immediate post impact fire. A post accident examination of the wreckage revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. A pilot operating another pipeline patrol airplane in the vicinity reported frequent severe-to-extreme turbulence about 1,000-2,000 ft above ground level. Data from an on-board GPS unit indicated that, while on the base leg of the airport traffic pattern for landing, the accident airplane's airspeed decayed 10 knots below the manufacturer's recommended approach speed for turbulent conditions. An autopsy performed on the pilot found significant existing atherosclerotic disease (60 to 80 percent) and described evidence of an acute, premortem, nonocclusive thrombosis of the left anterior descending coronary artery. The medical examiner's conclusion stated it "appears the decedent likely suffered an acute cardiac event while piloting his aircraft" and "died primarily due to hypertensive and atherosclerotic cardiovascular disease and that his multiple blunt force injuries likely contributed to his death." It is likely that the pilot was incapacitated due to the acute cardiac event and lost control of the airplane during the approach to land.

The private pilot was conducting a personal flight during day, instrument flight rules (IFR) conditions. The pilot checked in with an air route traffic control center, and, after radar data showed multiple changes in altitude that were not in accordance with the assigned altitudes, an air traffic controller queried the pilot about the altitude changes. The pilot reported an autopilot problem and then later requested clearance to deviate around weather at a higher altitude. The airplane passed through several sectors and controllers, and it was understood that the pilot was aware of the adverse weather due to the deviation information in the flight strip. The air traffic controller did not provide additional adverse weather information and updates to the pilot, as required by a Federal Aviation Administration order; however, general broadcasts of this weather information were recorded on the frequency the pilot was using before the accident. Multiple weather resources showed rapidly developing multicellular to supercell-type convective activity with cloud tops near 48,000 ft. Forecasts and advisories warned of potential strong to severe thunderstorms with the potential for moderate-to-severe turbulence, hail, lightning, heavy rains, and high wind. Radar data indicated that the pilot turned into the intense weather cells instead of away from them as he had requested. The pilot declared a "mayday" and reported that he had lost visual reference and was in a spin. Damage to the airplane and witness marks on the ground were consistent with the airplane impacting in a level attitude and a flat spin. No mechanical anomalies were noted that would have precluded normal operation before the loss of control and impact with the ground. The investigation could not determine if there was an anomaly with the autopilot or if the rapidly developing thunderstorms and associated weather created a perception of an autopilot problem. The autopsy identified coronary artery disease. Although the coronary artery disease could have led to an acute coronary syndrome with symptoms such as chest pain, shortness of breath, palpitations, or fainting, it was unlikely to have impaired the pilot's judgment following a preflight weather briefing or while decision-making en route. Thus, there is no evidence that a medical condition contributed to the accident. The toxicology testing of the pilot identified zolpidem in the pilot's blood and tetrahydrocannabinol and its metabolite in the pilot's cavity blood, which indicated that he was using two potentially impairing substances in the days to hours before the accident. It is unlikely that the pilot's use of zolpidem contributed to the accident; however, the investigation could not determine whether the pilot's use of marijuana contributed to the cause of the accident.

The non-instrument-rated pilot departed on a cross-country flight in a twin-engine turboprop airplane on an instrument flight plan. As the pilot neared his destination airport, he received heading and altitude vectors from air traffic control. The controller cleared the flight for the approach to the airport; shortly afterward, the pilot radioed that he was executing a missed approach. The controller then issued missed approach instructions, which the pilot acknowledged. There was no further communication with the pilot. The airplane collided with terrain in a near-vertical angle. About the time of the accident, the automated weather reporting station recorded a 300-foot overcast ceiling, and 5 miles visibility in mist. Examination of the wreckage did not reveal any anomalies that would have precluded normal operation. Additionally, both engines displayed signatures consistent with the production of power at the time of impact. The pilot's logbook indicated that he had a total of 1,281.6 flight hours, with 512.4 in multi-engine airplanes and 192.9 in the accident airplane. The logbook also revealed that he had 29.7 total hours of actual instrument time, with 15.6 of those hours in the accident airplane. Of the total instrument time, he received 1 hour of instrument instruction by a flight instructor, recorded about 3 years before the accident. The accident is consistent with a loss of control in instrument conditions.

The pilot reported that he had added fuel at the previous fuel stop and that he was using a fuel totalizer to determine the quantity of fuel onboard. After climbing to a cruise altitude of 14,000 feet above ground level, he discovered that the fuel mixture control was frozen and that he was unable to lean the mixture to a lower fuel flow setting. The pilot reported that because of the increased fuel consumption, he briefly considered an en route stop for additional fuel but decided to continue. During descent, the airplane experienced a complete loss of power in both engines, and the pilot made an emergency off-field, gear-up landing about 7 miles from the destination. The airplane impacted terrain and thick scrub trees, which resulted in substantial damage to both wings, both engine mounts, and the fuselage. A postaccident examination found that only a trace of fuel remained. The pilot also reported that there was no mechanical malfunction or failure and that his inadequate fuel management was partly because he had become overconfident in his abilities after 50 years of flying.

The instrument-rated pilot obtained a weather briefing prior to departure that contained surface observations along the route of flight, as well as significant meteorological (SIGMET) and airman's meteorological (AIRMET) information. The briefing also included convective weather advisories, a convective outlook, the area forecast, pilot reports, radar summary, and winds aloft information. The area forecast included overcast ceilings at 1,500 feet mean sea level (msl) with cloud tops at 6,000 feet msl, visibility between 3 and 5 miles, light rain and mist, and isolated thunderstorms with cumulonimbus tops to 35,000 feet msl. After the pilot departed, he established contact with air traffic control; the airplane was initially observed on radar heading toward the destination airport. An analysis of radar from the day of the accident indicated that isolated thunderstorms existed and that, almost 4 minutes after departing, the airplane encountered an area of developing rain showers and vertical updrafts. The airplane began a descending right turn followed by a brief climb, then another descent; its ground speed slowed from 202 knots to 110 knots before the data ended. At that time, the airplane was at 4,500 feet msl. A witness said he heard the airplane but was unable to see it due to the low cloud layer. A few moments later, he saw the airplane exit the cloud layer in a spin before it impacted the ground. A postaccident examination revealed no mechanical deficiencies that would have precluded normal operation of the airplane and engine.