WPR19LA066

The instrument rated pilot departed into marginal visual flight rules conditions between sunset and the end of civil twilight. Shortly after takeoff, he contacted air traffic control and stated that he was in the clouds at 5,000 ft mean sea level (msl) and requested an instrument landing system approach at the destination airport. The controller issued the airplane a discrete transponder code and asked the pilot if he wanted an IFR clearance; however, the pilot did not respond, and no further communications were received from the airplane. Radar data showed that the airplane entered a descending left turn before radar contact was lost about 3,050 ft msl. Witnesses and surveillance video indicated that the airplane descended out of the clouds in a steep, nose-low attitude and impacted terrain. The extensive fragmentation of the wreckage precluded a thorough examination of the airplane's flight controls, instruments, and other systems; however, no anomalies were noted during examination of the engines. AIRMETs for instrument flight rules (IFR), mountain obscuration, turbulence, and icing conditions were all valid for the area of the accident site at the time of the accident. Both the departure and destination airports reported overcast ceilings below 2,000 ft above ground level about the time of the accident, with surface temperatures just above freezing. An atmospheric sounding indicated a high potential for light rime icing and moderate turbulence at 5,000 ft in the vicinity of the accident site, and radar imagery suggested clouds and potential light icing conditions. There was no evidence that the pilot obtained a weather briefing before departure. Although impact damage precluded a thorough examination of the airplane's flight instruments, the restricted visibility and lighting conditions present at the time were conducive to the development of spatial disorientation, and the airplane's descending turn and high-energy impact are consistent with the known effects of spatial disorientation.

HISTORY OF FLIGHT On January 17, 2019, at 1645 Pacific standard time, a Piper PA23-250 airplane, N14372, was destroyed when it was involved in an accident near Ellensburg, Washington. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight. The flight originated from Bowers Field Airport (ELN), Ellensburg, Washington, about 1639, and was destined for McAllister Field Airport (YKM), Yakima, Washington, located about 28 nautical miles south. Radar data showed the airplane depart ELN to the northwest, make an approximate 180° left turn to the southeast, and then make a turn southwest before flying south. (See Figure 1). At 1644, the airplane had reached an altitude of 4,750 ft mean sea level (msl); shortly thereafter, it entered a descending left turn before radar data ended at 16:45:18 and 3,050 ft msl. The instrument rated pilot contacted air traffic control after departure and stated that he was in the clouds at 5,000 ft, and he requested the instrument landing system RWY27 approach at YKM. The controller issued the pilot a discrete transponder code and asked the pilot if he was requesting an IFR clearance, but the pilot did not respond, and no further communications were received from the airplane. Figure - Flight Track One witness at ELN reported that he helped the pilot clear snow from his airplane. The accident pilot indicated to him that he had hoped to conduct the flight in visual flight rules (VFR) conditions. The witness looked to the south and indicated that he could see the ridge to the south in some places but not in others and stated that the whole valley was covered by clouds "here and there." The accident pilot indicated that he would be contacting air traffic control for vectors around the weather. A witness near the accident scene heard the airplane flying low and looked up to see it "diving down sideways." A second witness stated that he heard the engines "gunning" and he looked up and saw a two-engine airplane descending nose-low before it impacted the ground. Video of the accident, which was taken from about 3 miles southeast of the accident site, was consistent with the witness observations. The video showed the airplane exiting clouds and remaining in an approximate 30° nose-low attitude and at a significant bank angle until it impacted the ground. METEOROLOGICAL INFORMATION AIRMETs for instrument flight rules (IFR), mountain obscuration, turbulence, and icing conditions were all valid for the area of the accident site at the time of the accident. The station models on the surface analysis chart surrounding the accident site depicted calm to light winds of 5 knots or less, overcast clouds, temperatures in the low-to-mid 30s °F, and dew point temperatures in the low 30s to high 20s °F, or temperature-dew spreads of 4°F or less. Several stations west, northeast, and east of the accident site reported snow showers, and a station south of the accident sitereport visibility restricted in mist or fog. The National Composite Radar Image depicted several areas of echoes associated with rain and snow showers extending over and north of the Ellensburg area and another area immediately south of the accident site. Very light intensity echoes were identified within 5 miles east and south of the accident site. The 1653 observation at YKM included 10 miles visibility, an overcast ceiling at 1,300 ft agl, temperature 3°C, and dew point 1°C. The end of civil twilight occurred at 1717 on the day of the accident. There was no evidence that the pilot obtained a weather briefing from an official, access-controlled source before departing on the flight. WRECKAGE AND IMPACT INFORMATION The wreckage debris path was orientated on a 213° magnetic heading and extended about 350 ft. Ground signatures and the orientation of the wreckage indicated that the airplane impacted the ground in a nose-low, left-wing-low attitude. The wreckage was highly fragmented; impact damage precluded determination of flight control continuity and examination of the flight instruments. Both engines were examined, and no anomalies were noted that would have precluded normal operation. The propellers were found separated from both engines. Both propeller assemblies displayed symmetry of impact damage. Chordwise scratches and leading-edge gouges were present on all blades. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy was conducted on the pilot by the King County Medical Examiner, Seattle, Washington, and the cause of death was attributed to multiple blunt force injuries. Toxicology testing performed by the FAA Forensic Sciences Laboratory was negative for ethanol. Tamsulosin was detected in liver and muscle specimens. Tamsulosin, brand name Flomax, is a urinary retention medication used to treat an enlarged prostrate. The pilot had reported the use of Tamsulosin on his most recent flight physical and no restrictions to flight were issued because of it. ADDITIONAL INFORMATION The FAA Civil Aeromedical Institute's publication, "Introduction to Aviation Physiology," defines spatial disorientation as a “loss of proper bearings; state of mental confusion as to position, location, or movement relative to the position of the earth.” Factors contributing to spatial disorientation include changes in acceleration, flight in IFR conditions, frequent transfer between visual flight rules and IFR conditions, and unperceived changes in aircraft attitude. The FAA’s Airplane Flying Handbook (FAA-H-8083-3B) describes some hazards associated with flying when the ground or horizon are obscured. The handbook states, in part, the following: The vestibular sense (motion sensing by the inner ear) in particular can and will confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in airplane attitude, nor can they accurately sense attitude changes that occur at a uniform rate over a period of time. On the other hand,false sensations are often generated, leading the pilot to believe the attitude of the airplane has changed when, in fact, it has not. These false sensations result in the pilot experiencing spatial disorientation.