History of Flight
On October 27, 2014, about 0740 mountain daylight time, a Mooney M20F airplane, N3539X, was substantially damaged when it impacted the ground just north of the Boulder Municipal Airport (KBDU), Boulder, Colorado. A postimpact fire ensued. The airline transport pilot was fatally injured. The airplane was registered to and operated by a private individual under Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was originating at the time of the accident and was en route to Rocky Mountain Metropolitan Airport (KBJC), Denver, Colorado, for routine maintenance.
Witnesses reported seeing the airplane take off from runway 08. Shortly after liftoff, the airplane banked left and continued north in a steep bank with a nose-low attitude. It impacted the ground nearly vertical, coming to rest on the north edge of Independence Road, just north of KBDU. Three witnesses provided statements to NTSB investigators; none reported hearing unusual sounds. Two additional witnesses observed the airplane bank left and roll inverted before impact. A third witness heard the engine accelerate, then quiet, before the impact sound.
Personnel Information
The pilot, age 35, held a commercial pilot certificate with airplane single-engine land and sea ratings, an airline transport pilot certificate with multi-engine land privileges and an EMB-145 type rating, and a flight instructor certificate with airplane single-engine rating. He held a first-class medical certificate without limitations issued October 3, 2014. His logbooks indicated at least 3,438 total hours and 1,151 hours as pilot-in-command. He completed a flight review in February 2014 and a two-hour checkout flight on September 27, 2014, during which the instructor noted he was cautious but slow in stall recovery and had difficulty with the landing gear handle.
Aircraft Information
The Mooney M20F (serial number 670076) was manufactured in 1966 and held a standard airworthiness certificate. It was powered by a Lycoming IO-360-A1A engine (200 hp) with a two-blade Hartzell propeller. The airplane was maintained under an annual inspection program; the actual records were destroyed in the fire. A digital copy showed an annual inspection on November 13, 2013, at 5,507.5 airframe hours, and a new baggage door installed on August 14, 2014, at 5,521.3 tachometer hours.
Meteorological Information
The closest weather station, at KBDU, reported at 0736: wind 150° at 8 knots, visibility 10 miles, clear sky, temperature 7°C, dew point 2°C, altimeter 29.87 inches. At 0756: wind 330° at 4 knots, visibility 10 miles, clear, temperature 6°C, dew point 2°C, altimeter 29.89 inches. Civil twilight began at 0657, sunrise at 0725; at 0740 the sun angle was 2.29° above the horizon.
Wreckage and Impact
The accident site was on the north side of the airport, outside the perimeter fence, at elevation 5,280 feet. The initial impact point was a crater in the road, about 6 inches deep and 24 inches long. The main wreckage came to rest 14 feet north of the crater, including the fuselage, empennage, wings, and engine/propeller assembly. The wreckage was charred, melted, and partially consumed by fire.
Examination of the cockpit controls showed the throttle forward (full power), mixture forward (rich), propeller control forward (high rpm), and landing gear handle in the retracted position. Both wings had flaps in the retracted position. The right and left main landing gear were consistent with retracted. The empennage partially separated due to impact and fire. No preaccident mechanical malfunctions were found with the airframe or flight controls.
Additional Information
Security camera footage from the Soaring Society of Boulder showed the airplane taxiing and on takeoff roll. The airplane was visible for about 18 seconds on the runway for at least 1,000 feet; the rotation and accident sequence were not captured due to sun position and camera angle.
Performance data from the Mooney M20F Owner's Manual for 5,000 feet, 41°F, 2,300 pounds, indicated a ground run of 900 feet and 1,500 feet to clear a 50-foot obstacle, with maximum climb rate at 1,100 feet and 108 knots indicated airspeed, in the takeoff configuration (gear down, flaps 15°, full rich, calm wind).
Medical and Pathological Information
An autopsy by the Boulder County Coroner on October 28, 2014, determined the cause of death as multiple blunt force injuries. Toxicological tests by the FAA's Civil Aerospace Medical Institute were negative for all tested substances.
Tests and Research
Engine examination revealed spark plug signatures consistent with normal operation. Magneto and leads were fire-damaged and could not be tested. Propeller blades showed rotational scoring and impact damage; one blade had its outboard portion separated and partially consumed by fire. No preaccident mechanical malfunctions were found with the engine that would have precluded normal operation. A small amount of fluid from the fuel divider tested positive for water.