History of Flight
On September 24, 2015, at 1908 central daylight time, an amateur-built Mustang II airplane, registration N929DS, impacted terrain during initial climb at Granbury Regional Airport (GDJ), Granbury, Texas. The pilot and passenger sustained fatal injuries, and the airplane was destroyed. The flight was conducted as a personal flight under 14 CFR Part 91. Day visual meteorological conditions prevailed, and no flight plan was filed. The airplane was departing for a local flight.
Witnesses at the north end of the runway reported that after the airplane took off to the south, it briefly leveled off and flew down the runway at low altitude. It then entered a steep nose-up climb, followed by a sudden roll to the right, and a steep nose-down descent. Video from a security camera about 700 feet away showed the airplane descending in a 20° to 30° nose-down attitude. The airplane impacted the terrain, and a postimpact fire ensued.
Personnel Information
The pilot was employed as a helicopter pilot for an air ambulance company, operating Bell 206L3 and 407 helicopters. He purchased the completed Mustang II on August 18, 2015, and had accumulated 33.5 hours in the accident airplane. His last biannual flight review was on June 3, 2014, in a Bell 206L3; his last fixed-wing flight review was not located during the investigation. It could not be determined when the pilot last practiced stall recoveries.
Aircraft Information
N929DS was an amateur-built, low-wing, single-engine airplane. On May 19, 2015, it was inspected in accordance with Federal Aviation Rule 43 Appendix D and found to be in a condition for safe operation. At that inspection, the airplane and engine had accumulated 402.88 hours. According to the pilot's logbook, at the time of the accident, the airplane had accrued no less than 436.3 hours.
Wreckage and Impact Information
The wreckage came to rest in a grass field near the departure end of runway 14. Impact signatures were consistent with a nose-low collision with terrain. The propeller, spinner, and hub fractured from the engine at the propeller flange and were partially embedded in the ground. The main wreckage, several yards away, consisted of the remainder of the airplane. A postimpact fire consumed much of the wreckage. Flight control continuity was established. Examination of the propeller found deep pitting and gouging on the leading edges of both blades, as well as deep chordwise scratches. One blade was fractured near its mid-span with grainy, gravelly fracture surfaces. No anomalies were detected with the airframe.
The engine was examined; continuity and compression were verified to each cylinder. The carburetor and magnetos were heat damaged and could not be tested. No preimpact defects were noted.
Several cockpit electronic devices with potential for data retention via non-volatile memory were sent to the NTSB laboratory for examination, but fire damage precluded data download. A GoPro Hero 2 camera found in the wreckage was also sent for download.
Medical and Pathological Information
An autopsy performed by the Tarrant County Medical Examiner listed the cause of death as "multiple blunt force injuries due to [an] aircraft crash with [a] post-crash fire" and ruled the manner as accident. Forensic toxicology by the FAA Civil Aerospace Medical Institute on specimens from the pilot was negative for all tested substances.
Tests and Research
Examination of the GoPro camera revealed no damage, and image recording information was extracted from the SD card. The card contained 26 aviation-related video files, of which 18 were recorded in the accident airplane. None of those 18 contained a recording of the accident flight.
Of the 18 video files, eight recordings showed a maneuver similar to that described by witnesses. In these recordings, the aircraft began a takeoff roll, became airborne, and remained at low altitude as it traveled down the runway. Near the departure end, it climbed quickly and then was brought to a level attitude. In most of these recordings, the aircraft exhibited a varying degree of right roll, either simultaneously with leveling or moments thereafter. During these eight recordings, the airspeed indicator never displayed a value less than 80 mph. In one recording, an electronic tone was heard on the audio track, consistent with the stall warning tone from previous landings. At that time, the indicated airspeed was approximately 105 mph, and the aircraft's attitude was about 10° in pitch and 45° in roll to the right, while the pilot was exiting the climb and leveling. Though the stall warning horn sounded briefly, there were no other indications the aircraft was approaching a stalled condition.