History of Flight
On September 20, 2020, at about 1050 central daylight time, a Piper PA-46-310, registration N236KM, was substantially damaged when it impacted terrain near Hilltop Lakes, Texas. The commercial pilot and three passengers sustained fatal injuries. The flight was operating under Title 14 Code of Federal Regulations Part 91 as a personal flight.
While in cruise flight at 19,000 ft mean sea level, the pilot declared an emergency to air traffic control, reporting a loss of engine power and the need to divert. The pilot selected Hilltop Lakes Airport (0TE4), approximately 5 miles south of the position. Archived ADS-B data showed that the airplane descended from 19,000 ft about 5 miles west of the airport, circled once, and then tracked toward a final approach. The last data point indicated the airplane about 1 mile north of the approach end of runway 15 at an altitude of 1,250 ft, groundspeed 169 knots, on a track of 145°. Approximately 12 minutes and 45 seconds elapsed from cruise to the last point, yielding an average descent rate of 1,392 ft per minute.
Witnesses located about 1/4 mile south of the runway end reported seeing the airplane appearing to take off, but noted the propeller was not turning. They observed the airplane in a left bank just before the nose dropped and it impacted the ground in a near vertical attitude.
Meteorological Information
Winds aloft reported near the airport about 9 minutes after the accident included: at 1,306 ft MSL, wind from 037° at 15 knots; at 2,458 ft, 051° at 19 knots; at 4,861 ft, 062° at 20 knots; and at 7,046 ft, 059° at 21 knots.
Wreckage and Impact Information
The airplane came to rest along a road about 200 ft south of the airport property. Impact was in a nose-low, near-vertical attitude, causing substantial damage to the fuselage and both wings. A strong odor consistent with jet fuel was noted, and the left-wing fuel tank was breached.
The cockpit area showed extensive aft crushing and tearing, resulting in fuselage separation. Flight control cable continuity was confirmed from cockpit to control surfaces except for separations consistent with wreckage recovery cuts and impact forces. The flap actuator rod was extended about 6 inches, indicating flaps were fully extended at impact.
During post-recovery examination, liquid consistent with Jet-A fuel was observed pouring from the vapor return line at the right wing root and from the leading edge near the inboard end of the fuel tank.
The engine sustained severe impact damage and deformation. The center firewall was deformed. Components including the starter, alternator, and air conditioning compressor remained attached. No evidence of uncontained engine failure or undercowl fire was found. The fuel control unit and turboprop governor lines were intact; the Py line fittings at the governor were secure but could be backed off without a wrench, and the P3 line fitting was finger tight. No debris accumulation was noted on the magnetic chip detector or in fuel/oil filters. Residual fuel in the fuel filter bowl contained a small amount of shiny particulate.
The accident airplane was equipped with a Shadin Avionics engine trend monitor (ETM), which recorded data from the flight. Logged events included multiple unsuccessful engine start attempts earlier in the day, torque exceedances, power checks during cruise, and an engine off log at 10:41:48 CDT, when Ng dropped below 48%.
Additional Information
The JetProp LLC Airplane Flight Manual supplement for emergency procedures related to engine power loss in flight superseded the original procedures. The first item on the Engine Failure (Mechanical Failure) checklist directed trimming for 90 knots indicated airspeed. Track data showed groundspeed varied between 122 and 172 knots during the descent. The Power Off Landing checklist instructed establishing best gliding angle at 90 KIAS, with a note to establish a spiral pattern to arrive at 1,500 ft above the field at the downwind position. A second note advised using flaps as necessary and slowing to 77 KIAS with flaps fully extended for the shortest landing. When the airplane was on a downwind leg, reported altitude was about 5,000 ft above ground level.