History of Flight
On February 8, 2010, at about 1250 Pacific standard time, an experimental Yakovlev Yak 52, registration N52VY, collided with terrain while maneuvering near Redlands, California. The owner/pilot was operating under 14 CFR Part 91. The commercial pilot and a pilot-rated passenger were killed; the airplane sustained substantial damage. The local personal flight departed Redlands about 1230. Visual meteorological conditions prevailed, and no flight plan was filed.
Multiple witnesses were interviewed. One witness observed the airplane performing aerobatics, then returning to the airport. The pilot shut down, deplaned, and shortly thereafter boarded and departed again, heading to the aerobatic box northeast of the airport. Over about 10 minutes, the airplane completed several loops and other maneuvers. The witness saw the airplane in a rapid descent with a nose-low attitude and wings rocking about the longitudinal axis.
Another witness stated the pilot asked for a funnel to add oil to the onboard smoke system. The airplane then departed and performed aerobatics for 10–15 minutes. The witness observed the airplane at low altitude beginning a spin with white smoke from the smoke machine. The rotation increased as the airplane neared terrain and subsequently crashed.
Personnel Information
The 27-year-old pilot held a commercial pilot certificate with single- and multi-engine land airplane and rotorcraft-helicopter ratings, plus an instrument airplane rating. He held a second-class medical certificate issued October 30, 2006, with a limitation to wear corrective lenses. According to his logbook, he had 277.8 total flight hours, including 188.7 in single-engine airplanes, 67.3 in rotorcraft, and 21.1 hours in the Yak 52 (7.7 hours dual aerobatic training and 5.2 hours solo aerobatic).
The 29-year-old pilot-rated passenger held a commercial pilot certificate with multi-engine land and instrument airplane ratings, and a private pilot certificate with single-engine land rating. She held a third-class medical certificate issued March 8, 2007, with no limitations. No personal flight records were found; on her last medical application, she reported 200 total flight hours. Both were California Air National Guard officers who flew MQ-1 Predator unmanned aircraft systems. The pilot was positioned in the front seat, passenger in the back; both were secured with shoulder harnesses.
Aircraft Information
The Yak 52 was manufactured in 1985 and registered in the United States in July 2002. It is a single-engine, two-seat tandem, low-wing primary trainer with metal construction and full aerobatic capability. The engine was a Vedenev M-14P radial rated at 360 horsepower, with a three-bladed wood/composite propeller. No maintenance logbooks were found; copies of maintenance were obtained from the facility used by the pilot. At the last condition inspection on February 24, 2009, airframe time was 963 hours; engine time was 1,402 hours. Hours accumulated since then are unknown.
Wreckage and Impact
The wreckage was located at an elevation of about 1,660 feet msl, about 1.2 nautical miles from Redlands airport on a bearing of 60 degrees, on relatively flat terrain with rocks and low vegetation. The main wreckage, including fuselage, tail, and wings, came to rest within the aerobatic box. A shallow crater was a few feet aft of the wreckage. The entire wreckage was upright in a relatively level attitude. The nose was pushed back into the fuselage, accordioning the skin. The bottom skin of the tail section detached, remaining attached only by top skin; the tail scorpioned forward. The propeller blades splintered near the engine. The left wing's leading edge was wrapped around a boulder.
Medical and Pathological Information
The San Bernardino County Coroner completed autopsies on both occupants. Specimens from the pilot were tested by the FAA Toxicology and Accident Research Laboratory; results were negative for carbon monoxide, volatiles, and tested drugs.
Tests and Research
A Safety Board investigator examined the airplane at a salvage facility on March 25, 2010, with FAA inspectors present. The left wing remained attached; aileron and flap were attached. The wing sustained aft crush deformation to the inboard section. The right wing remained attached, leading edge accordioned. The empennage was intact; control cables were severed by recovery personnel. Rudder and elevator continuity was verified from control surfaces to the entangled cockpit area, but cockpit continuity could not be confirmed due to crush damage. No evidence of mechanical malfunctions or failures was found.
Additional Information
Aerobatic Maneuvers
Two pieces of paper labeled "International Aerobatic Club" were found on the pilot's kneeboard. An industry expert identified these as a "known sequence" for a sportsman-level contest. The pilot had pages showing how maneuvers should be performed based on wind direction and order. The expert noted that pilots sometimes deviate to practice specific maneuvers.
Video
A witness recorded a short video of the airplane on a cell phone. It showed several seconds prior to impact, with a smoke trail from the onboard smoke system. The video quality was poor, preventing definitive analysis of control deflections or propeller rpm. Yak 52 experts viewed the video; one stated the smoke trail indicated a spin of at least three turns, likely fully developed. The smoke "corkscrew" tightened after two turns, suggesting a lower nose attitude and possible recovery. He concluded the airplane appeared to be in a conventional spin that recovered at too low an altitude for safe flight, resulting in a low-speed, high-descent-rate impact.
Human Factors
According to an FAA Research Psychologist, the Predator's Stability Augmentation System prevents aerobatic maneuvers, and most flights involve slow, level attitudes. He stated that flying aerobatics in a Yak is very different from piloting a Predator, and Predator experience did not contribute negatively. A U.S. Air Force flight surgeon noted potential areas of concern for transitioning from unmanned to manned aircraft, including negative transference and physiologic de-conditioning, but did not apply these directly to the accident.