Background
On August 20, 2011, about 1315 eastern daylight time, an amateur-built Lancair IV P (N71DM) and a Yakolev Yak-55M (N521BC) collided near Hammonton Airport (N81), Hammonton, New Jersey. Both airplanes sustained substantial damage. The certificated private pilot of the Lancair was fatally injured, and the certificated private pilot of the Yak, who parachuted from his airplane, was seriously injured. Visual meteorological conditions prevailed, and no flight plan had been filed for either flight. The flights were conducted under 14 Code of Federal Regulations Part 91.
Flight History
The Lancair departed South Jersey Regional Airport (VAY), Mount Holly, New Jersey, for an undetermined destination. A manager at Flying W Airport (N14) stated the pilot had discussed visiting a friend at N81 and indicated he intended to land there. The Yak departed N81 on a local aerobatic flight. According to friends of the Yak pilot, he was performing maneuvers in an aerobatic practice area, also known as the "aerobatic box," while being observed by an observer/coach. The airspace east of runway 3/21 was uncontrolled.
Witness Accounts
A ground witness reported seeing the Yak take off and begin aerobatic maneuvers. After about 20 minutes, she observed the Yak make a steep climb and then a steep dive. As it did so, she saw a white airplane traveling "really fast" in level flight collide with the Yak. Neither airplane appeared to alter course before the collision. The observer, seated across the runway with radios tuned to the aerobatic box frequency and the CTAF, noted that the Yak pilot would radio intended maneuvers for postflight critique. The maneuver during the accident was a hammerhead stall. The observer saw the Yak climb, heard another airplane (a Cessna), and called the Yak pilot to advise of the Cessna. He did not see the Lancair approach due to sun glare but saw the Yak break into two pieces and the Lancair lose a wing section before descending. He shouted for the Yak pilot to jump and estimated the Yak was about 1,600 to 1,700 feet above the ground when the pilot parachuted. Neither the Cessna nor the Lancair pilot transmitted on the radio prior to the accident, according to the observer.
The pilot of a Cessna 172, returning to N81, reported seeing the Yak climbing vertically with smoke. He crossed the runway to fly a downwind leg on the west side. As he turned, he saw the Yak again, which overflew him closely before heading straight down. He then saw an open parachute and avoided it. He stated his radio was on the CTAF, and he received no response to his call; he never heard the Lancair pilot transmit. A pilot-rated passenger in the Cessna gave similar observations.
The Yak pilot, interviewed later in the hospital, wrote that he thought his airplane was struck while climbing. He had entered the hammerhead maneuver from inverted flight, climbed vertically, and planned to roll into the wind. He did not know a collision had occurred until on the ground. He stated he completed a climbing clearing turn before the maneuver.
Radar and Data
Radar data from the FAA showed tracks for all three airplanes, all using transponder code 1200. The tracks converged near N81, but fidelity limitations made the Yak and Lancair difficult to distinguish. The Cessna descended to about 1,100 feet at the time of the accident. The Yak track remained east of the runway with missing data points. The Lancair track showed it approaching from the west at altitudes averaging about 3,500 feet, dipping to 3,300 and climbing back to 3,500. Near the airport, the Lancair and Cessna tracks converged but did not overlap, with the Lancair about 2,300 feet above the Cessna. The Yak track then disappeared, and the display froze. Subsequent returns could not be identified. Radar plots showed Lancair ground speeds near N81 of about 190 knots.
The Yak was equipped with an electronic flight information system (EFIS) that recorded six parameters every 10 seconds. The last four recorded times (1311:50 to 1312:20) showed the Yak climbing, then descending, with heading and airspeed changes consistent with aerobatic maneuvers.
Wreckage and Injuries
The Lancair impacted the ground about 3,800 feet from runway 21 on a 060-degree heading, nose-down slightly inverted. Tree cuts and wreckage distribution were consistent with a vertical impact. The main Yak wreckage came to rest about 2,400 feet from the runway, also nose-down. The outboard 4 feet of the Lancair's left wing was found near the Yak wreckage, and the Yak's aft fuselage/tail section was separated. No paint transfers were observed on either separated piece. The Yak pilot parachuted into woods and was transported to a hospital. Toxicology tests on the Lancair pilot showed no anomalies.
Regulations
The accident site was in uncontrolled airspace. A Certificate of Waiver (CW) issued in 2009 allowed aerobatic flight within a one-nautical-mile radius of runway 21 at N81 between 1,500 and 3,500 feet agl, with specific notification and observer requirements. A NOTAM was in effect for the aerobatic area from 1300-2359 UTC. The Lancair pilot had no record of obtaining a preflight briefing. Federal Aviation Regulations Part 91.103 and 91.113 mandate preflight familiarity and see-and-avoid vigilance. The aerobatic box was permanently closed shortly after the accident.