Boulder, CO, USA
N3539X
MOONEY M20
Witnesses reported that, just after takeoff, the airplane rolled left to an inverted position and impacted terrain. One witness reported hearing abnormal engine sounds just before the impact, but other witnesses did not recall hearing anything abnormal. The pilot was departing to the east with a direct crosswind, and the sun was most likely in the pilot's eyes, but it could not be determined what effect this would have on the pilot's control of the airplane. The throttle, mixture, and propeller controls were found in the full power, rich mixture, and high rpm positions, respectively. However, the propeller blade signatures were consistent with the engine operating at a low power setting. A trace amount of water was found in the fuel divider; however, this could have come from post-accident firefighting measures. Due to impact and postcrash fire damage, fuel from the fuel tanks and lines was not available for examination, and the damage also precluded a functional test of the engine and related systems. The investigation could not determine if the engine lost power before the airplane rolled inverted.
HISTORY OF FLIGHTOn October 27, 2014, about 0740 mountain daylight time (MDT), 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 the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight was originating at the time of the accident and was en route to Rocky Mountain Metropolitan Airport (KBJC), Denver, Colorado. According to family and friends of the pilot, he was taking the airplane to KBJC to have routine maintenance performed on the airplane. Several witnesses reported seeing the airplane as it took off from runway 08 (4,100 feet by 75 feet, asphalt). Shortly after liftoff, the airplane banked to the left and continued to the north in a steep bank and a nose low attitude. The airplane impacted the ground, nearly vertical, and came to rest on the north edge of Independence Road, just north of KBDU. Investigators with the National Transportation Safety Board (NTSB) took statements from 3 witnesses. These witnesses observed the airplane in different phases of flight. None of the witnesses reported or recalled hearing anything unusual or abnormal prior to the accident. Three additional witnesses provided written statements to local law enforcement officers. Two of these witnesses observed the airplane take off, bank to the left, and continue rolling inverted until it impacted the road. The third witness did not see the airplane in the air. This witness heard the engine accelerate and then "quiet" before the "thump" or impact with the ground. The witness commented that the sound was not right just prior to the impact with the ground. PERSONNEL INFORMATIONThe pilot, age 35, held a commercial pilot certificate with airplane single engine land and sea ratings and an airline transport pilot certificate with airplane multiengine land privileges and a type rating in an EMB-145. He also held a flight instructor certificate with an airplane single engine rating. He was issued a first class airman medical certificate without limitations on October 3, 2014. The pilot's family provided investigators three of his logbooks for review. The most recent logbook was maintained digitally. A review of the logbook indicated that the pilot had logged no less than 3,438 hours total time; 1,151 hours as pilot in command. On the pilot record for his insurance application, the pilot wrote that he successfully completed a flight review or equivalent in February 2014. A review of his digital logbook did not illustrate which airplane this was conducted in or if it was part of training with his employer. The pilot completed a 2 hour checkout flight with a flight instructor on September 27, 2014. The flight instructor stated that he was a confident and cautious pilot. He commented that the pilot was "slow" in stall recovery and had some "difficulty" with the landing gear handle in the airplane. During the checkout flight they did 15 to 20 touch and go landings in addition to stalls. AIRCRAFT INFORMATIONThe accident airplane, a Mooney M20F (serial number 670076), was manufactured in 1966. It was registered with the Federal Aviation Administration (FAA) on a standard airworthiness certificate for normal operations. A Lycoming IO-360-A1A engine rated at 200 horsepower at 2,700 rpm powered the airplane. The engine was equipped with a 2-blade, Hartzell propeller. The airplane was registered to a private group, operated by the pilot, and was maintained under an annual inspection program. The actual maintenance records were believed to have been destroyed in the post-impact fire. A review a digital copy of the maintenance records indicated that an annual inspection had been completed on November 13, 2013, at an airframe total time of 5,507.5 hours. On August 14, 2014, the installation of a new baggage door was completed at a tachometer time of 5,521.3 hours. METEOROLOGICAL INFORMATIONThe closest official weather observation station was located at KBDU, less than a mile from the accident site. The elevation of the weather observation station was 5,288 feet msl. The routine aviation weather report (METAR) for KBDU, issued at 0736, reported, wind 150 degrees at 8 knots, visibility 10 miles, sky condition clear, temperature 7 degrees Celsius (C), dew point temperature 2 degrees C, altimeter 29.87 inches. The METAR for KBDU, issued at 0756, reported wind 330 degrees at 4 knots, visibility 10 miles, sky condition clear, temperature 6 degrees C, dew point temperature 2 degrees C, altimeter 29.89 inches. According to the United States Naval Observatory, Astronomical Applications Department Sun and Moon Data, civil twilight began at 0657 and the sunrise was recorded at 0725 MDT. At 0740 the suns angle was calculated at 2.29 degrees above the horizon and 108.69 degrees from north. AIRPORT INFORMATIONThe accident airplane, a Mooney M20F (serial number 670076), was manufactured in 1966. It was registered with the Federal Aviation Administration (FAA) on a standard airworthiness certificate for normal operations. A Lycoming IO-360-A1A engine rated at 200 horsepower at 2,700 rpm powered the airplane. The engine was equipped with a 2-blade, Hartzell propeller. The airplane was registered to a private group, operated by the pilot, and was maintained under an annual inspection program. The actual maintenance records were believed to have been destroyed in the post-impact fire. A review a digital copy of the maintenance records indicated that an annual inspection had been completed on November 13, 2013, at an airframe total time of 5,507.5 hours. On August 14, 2014, the installation of a new baggage door was completed at a tachometer time of 5,521.3 hours. WRECKAGE AND IMPACT INFORMATIONThe accident site was located on the north side of the airport, outside of the perimeter fence. The accident site was at an elevation of 5,280 feet msl. The initial impact point was characterized by a crater in the road, approximately 6 inches at its greatest depth and 24 inches at its greatest length. Fragmented windscreen surrounded and was found inside of the crater. Ground scars outside and adjacent to the crater were consistent with the propeller blades and airplane. The main wreckage came to rest 14 feet north of the crater, on the side of the road and adjacent a barbed wire fence. The main wreckage included the fuselage, empennage, both wings, and the engine and propeller assembly. The wreckage was charred, melted, partially consumed by fire, and exhibited impact damage. The fuselage included the cabin area and instrument panel. The instrument panel was damaged by the fire and impact forces and no reliable readings were available. The throttle quadrant, which included the throttle control, mixture control, and propeller control, was damaged by the fire. The throttle control was forward in a position consistent with full power. The mixture was in a forward position consistent with a rich mixture. The propeller control was forward in a position consistent with high rpm. The landing gear handle was in a position consistent with the landing gear retracted. The right wing included the right aileron and right wing flap. The right wing remained attached to the fuselage and exhibited impact and fire damage at the root and along the leading edge of the wing. The right wing flap appeared to be in the retracted or zero-flap position. The right aileron remained attached and exhibited fire damage on the inboard portion of the control surface. The flight control was continuous from the aileron inboard to the cabin and flight yoke. The right main landing gear was in a position consistent with a retracted assembly. The left wing included the left aileron and left wing flap. The left wing remained attached to the fuselage and exhibited impact and fire damage along the entire wing. The left wing tip was crushed aft and folder over. The left wing flap appeared to be in the retracted or zero-flap position. The left aileron remained attached and exhibited fire damage along the entire control surface. The flight control was continuous from the aileron inboard to the cabin and flight yoke. The left main landing gear was in a position consistent with a retracted assembly. The empennage included the horizontal and vertical stabilizer, rudder, and elevators. The empennage separated partially from the fuselage due to impact and fire damage. The entire assembly exhibited impact and fire damage. The flight controls were continuous from the rudder and elevators inboard to the cabin through impact and fire damage. No preaccident mechanical malfunctions or failures were found with the airframe or flight controls that would have precluded normal operation. ADDITIONAL INFORMATIONSecurity Camera Footage The Soaring Society of Boulder's security system captured several angles of an airplane, consistent in time, color, and circumstances with the accident airplane. This airplane was observed both during the taxi and takeoff roll. One angle illustrated the airplane taking the runway about 0740:16. The airplane passed through the screen/frame of four different camera angles and was in view for a total of 18 seconds. The rotation, takeoff, and accident sequence were not captured due to sun position and camera angle. The airplane appeared to remain on the ground in all four frames, for at least 1,000 feet. Performance The Owner's Manual for the Mooney Aircraft, Inc. Model M20F, provided the following performance information for the takeoff and climb with the following conditions: Altitude 5,000 feet, temperature 41 degrees Fahrenheit, weight 2,300 pounds - 900 foot ground run - 1,500 feet to clear a 50 foot obstacle - maximum rate of climb at 1,100 feet and 108 knots indicated airspeed The takeoff configuration for this performance included landing gear down, full rich mixture, 15 degrees flaps, calm winds, and a hard surface runway. MEDICAL AND PATHOLOGICAL INFORMATIONThe autopsy was performed by the Office of the Boulder County Coroner on October 28, 2014. The autopsy concluded that the cause of death was "multiple blunt force injuries" and the report listed the specific injuries. The FAA's Civil Aerospace Medical Institute, Oklahoma City, Oklahoma, performed toxicological tests on specimens that were collected during the autopsy (CAMI Reference #201400253001). Results were negative for all tests conducted. TESTS AND RESEARCHEngine Examination The upper bank of spark plugs were removed and exhibited signatures consistent with normal operation when compared to a Champion Spark Plug Chart. The magnetos and leads were fire damaged and could not be functionally tested. Impact and fire damage precluded rotational confirmation of gear and valve train continuity. The number one and number three cylinders were removed to facilitate the examination. Engine continuity was confirmed visually. The propeller remained partially attached to the engine at the propeller flange. The blades were labeled "A" and "B" for identification purposes. Blade A exhibited impact and fire damage and rotational scoring on the face of the blade. Blade A was relatively straight. Blade B exhibited impact and fire damage. The outboard portion of the blade separated and was partially consumed by fire. The remainder of the blade was relatively straight. No preaccident mechanical malfunctions or failures were found with the engine that would have precluded normal operation. A small amount of fluid was noted in the fuel divider on the top of the engine. Prior to disassembly the divider appeared intact without impact or fire damage and did not appear to be compromised. The fluid tested positive for water content.
The loss of airplane control for reasons that could not be determined by the postaccident examination, which was limited due to impact damage and postcrash fire.
Source: NTSB Aviation Accident Database
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