History of Flight
On March 21, 2016, at about 1201 Pacific daylight time, an Airborne XT912 weight-shift control aircraft, registration N670EM, was destroyed when it struck a fence and a roadway shortly after takeoff from Northrop/Hawthorne Municipal Airport (HHR) in Hawthorne, California. The student pilot sustained fatal injuries. The aircraft was owned and operated by Pacific Blue Air (PBA) of Venice, California. The instructional flight was conducted under 14 Code of Federal Regulations Part 91 in visual meteorological conditions; no flight plan was filed.
Multiple witnesses reported that the aircraft began its takeoff roll on runway 25 from a point before the displaced threshold. Immediately after liftoff, the aircraft banked and turned right, continuing until its flight track was nearly perpendicular to the runway heading. The initial segment was a climb but transitioned to a descent as the roll continued. Witness estimates of maximum altitude ranged from 40 to 200 ft, and maximum bank angle estimates ranged from 45° to 90°. All witnesses stated that engine rpm remained constant or increased during the flight and that the engine continued to run until impact. No other aircraft were mentioned.
The aircraft struck the airport perimeter fence and then impacted a four-lane road north of the airport, roughly parallel to runway 25. On impact, the aircraft immediately caught fire. A water pumping/construction crew working about 100 ft away responded within seconds, attempting to rescue the pilot and extinguish the fire. Two Los Angeles County Sheriff's deputies responded within a minute. Air traffic control tower personnel notified HHR operations, who responded within minutes. Los Angeles County Fire Department equipment and personnel arrived shortly after. The pilot was extracted and transported to a hospital. The wreckage was examined on scene by FAA and NTSB personnel later that day and recovered for further examination.
Pilot Information
The pilot held an FAA student pilot certificate issued in May 2014. According to her logbook, her first flight was in October 2013, and she flew about two to three times per month thereafter. All flight time was in weight-shift control aircraft. She accrued about 38 hours in an Evolution Revo before transitioning to the accident aircraft on June 8, 2015, accumulating about 21 hours in it. Her first solo flight was on November 2, 2015, with about 48 hours total experience. The logbook listed eight solo flights totaling 6.9 hours. Her most recent flight, a solo cross-country, was on March 16, 2016.
About three days before the accident, the pilot experienced a snowboarding accident, striking her head or neck. She wore a helmet, did not lose consciousness, but suffered a "strained neck." Her fiancé reported she was sore but otherwise unchanged. A PBA co-owner saw the pilot arrive at the airport and stay in her car on the phone for about 20 minutes; when she entered the hangar, she appeared "slightly agitated." Telephone records showed five calls and one text between 1040 and 1122.
Aircraft Information
The aircraft, commonly called a "trike," was registered as a light sport aircraft. It was manufactured in 2007 and equipped with a Rotax 912 series engine. Maximum takeoff weight was 992 lbs. The aircraft was equipped with an "SST" model wing, described by the manufacturer as a high-performance flex wing using struts for negative loads. The most recent annual condition inspection was on June 3, 2015, and the most recent 100-hour inspection on November 10, 2015. Maintenance records showed no indications of prior significant damage or problems.
Wreckage and Impact Information
The wreckage was about 280 ft north of runway 7/25 centerline and 1,400 ft west of the east end of the paved runway. The aircraft struck a 6-ft-high chain link fence and impacted the road about 15 ft north of the fence, coming to rest at the north edge of the road adjacent to a fenced electrical enclosure. The fence damage, road scar, and wreckage formed a line perpendicular to the runway.
Most wreckage was tightly contained except for the right main wheel assembly and a few fragments. The airframe and wing structure consisted of aluminum tubing with steel cables; some tubes were fire-damaged. The carriage rested on its right side, nose pointing southeast. All steel cables remained intact. The forward carriage frame and nose gear were separated by fracture and fire. The right wheel assembly was separated above its support struts, showing crush damage consistent with fence contact. Seats were not identified, consistent with fire consumption. Four instruments (airspeed indicator, radio, transponder, EFIS) were severely fire-damaged. The airframe recovery parachute was out of its container, reefed/folded, partially extended, and much was fused or consumed by fire. The parachute extraction rocket was absent its propellant, consistent with ground fire consumption.
Detailed examination found no evidence of pre-impact mechanical deficiencies that would preclude normal flight. The engine remained attached to its steel frame and showed no pre-impact failures but sustained significant impact and fire damage, preventing determination of pre-accident operability. The three-blade composite propeller remained attached; two blades were separated from the hub, and all damage was consistent with impact with engine operating.
Additional Information
Air traffic control transcripts and radar data indicated that a DeHavilland DHC-6 landed on runway 25 about 40 seconds before the accident aircraft was cleared for takeoff from the same runway. The local controller did not issue a wake turbulence advisory. The DHC-6 pilots reported landing weight about 10,500 lbs with 20° flaps and approach speed 75 knots.
A wake vortex study using the NASA Langley APA algorithm indicated that meteorological conditions and relative times allowed for a possible wake encounter. The DHC-6 left vortex could have been in a position to be encountered by the accident aircraft between 60 and 80 seconds after the DHC-6 overflew the threshold. The residual vortex strength could have exceeded the roll control capability of the accident aircraft, with induced rolling moments up to about four times the aircraft's roll capability.
Medical and Pathological Information
An autopsy determined the cause of death as multiple traumatic injuries. No significant natural disease was identified. Toxicology found 0.22 ug/dl diphenhydramine in chest blood and 0.05 ug/mL benzoylecgonine in vitreous fluid. Diphenhydramine is a sedating antihistamine; benzoylecgonine is a cocaine metabolite.