Flight History
On March 20, 2010, about 1145 eastern daylight time, a Piper PA-32R-300 (N823AG) and an amateur-built Sentman RV-6 (N788LL) collided in flight approximately 3 nautical miles southeast of Williston Municipal Airport (X60) in Williston, Florida. The PA-32, registered to ARO Wing LLC and operated by a private pilot, had departed Deland Municipal-Sydney H Taylor Field about 1115 with a planned destination of X60. The RV-6, registered to and operated by a private pilot, departed Ocala International-Jim Taylor Field about 1135 also with a planned destination of X60. Both flights were conducted under 14 CFR Part 91 in visual meteorological conditions with no flight plans filed. No witnesses observed the collision, but several local residents reported hearing a loud bang and subsequently seeing pieces of aircraft falling.
Radar data from the United States Air Force showed two targets with converging flight paths. The aircraft further north (identified as the PA-32 based on its transponder) was squawking code 1200 with Mode C altitude. The southern aircraft (the RV-6) had no transponder and was detected only as a primary radar target. The primary-only aircraft approached the collision site on a true ground track of about 328 degrees, while the transponder-equipped aircraft approached on a true track of about 294 degrees. The PA-32 was about 15 nautical miles from the accident site at 1138, descending from 5,200 to 1,700 feet msl at about 132 knots ground speed, and made a gradual left turn about 2 miles before impact. The RV-6 departed runway 36 at OCF, turned left to a northwesterly heading, then began a slow right turn about 4 miles before impact, consistent with maneuvering for the downwind leg of the traffic pattern at X60.
Personnel Information
The PA-32 pilot, aged 59, held a private pilot certificate with single-engine land and instrument ratings, last updated May 27, 2009, and a second-class medical certificate issued January 14, 2010, with a restriction for glasses. He reported 345 total civilian flight hours. The passenger in the right front seat, the pilot's spouse, held no FAA certificates. The RV-6 pilot, aged 73, held a private pilot certificate with single-engine land rating, last updated May 29, 2008, and a third-class medical certificate issued May 27, 2008, reporting 231 total civilian flight hours.
Aircraft Information
The PA-32 was a 1976 red and black single-engine low-wing airplane, serial number 32-7780066, equipped with a Lycoming IO-540 engine. Maintenance logbooks were not located. The RV-6 was an unpainted low-wing amateur-built experimental airplane, serial number 002, manufactured in 2007, powered by an XP360 180-hp engine with a Hartzell variable-pitch propeller. Its engine logbook showed an annual inspection in October 2009 at 74.3 total hours.
Meteorological Information
The Ocala AWOS at 1135 reported wind from 110 degrees at 4 knots, visibility 10 statute miles, clear skies, and altimeter 30.13 inches of mercury. Astronomical data indicated the sun was 50 degrees above the horizon on an azimuth of 135 degrees around the accident time.
Communications
No FAA facility recorded communications with either aircraft in the 15 minutes before the accident. X60 management stated the airport does not record UNICOM (122.8 MHz) communications. It is unknown if the pilots communicated with each other.
Airport Information
Williston Municipal Airport (X60) is uncontrolled, elevation 76 feet msl, with runway 23 (6,668 feet long) using left-hand traffic patterns.
Wreckage and Impact
The wreckage of both aircraft came to rest within 100 yards of each other, about 3 nautical miles southeast of X60. The RV-6 debris and the left outboard wing section of the PA-32 were in a pasture. The PA-32 fuselage came to rest inverted in a wooded area, heading 204 degrees magnetic, and a postimpact fire consumed the forward fuselage, engine, and surrounding terrain. The tail section was in an adjacent tree; the stabilator assembly was found about 35 feet away, largely intact. The RV-6 came to rest upright in an open field, heading 090 degrees magnetic, with collapsed landing gear, deformed wings and empennage, and the engine partially embedded in the ground.
Examination of the PA-32 revealed the vertical fin attached to the aft fuselage, wedged in a tree. The aft fuselage was breached and separated at the aft cargo door jamb. The left wing had separated about 7 feet 8 inches outboard, showing leading-edge propeller strike damage at about a 45-degree angle through the main spar. The left aileron exhibited a bowed condition and a 45-degree tear consistent with propeller strike. The right wing was detached with fire damage. The ventral fin had a concave right leading edge. The stabilator was separated with dents and creases.
The RV-6 came to rest with propeller blades and lower engine embedded 6 inches into the ground. The right cockpit wall was pushed inward with red and black paint transfer on the glare shield. The canopy was shattered; several Plexiglas shards had red paint. Control continuity was established for all flight controls. The left and right wings were displaced upward. The right vertical stabilizer and rudder were impact-damaged and separated; the separated portion matched the crushed left horizontal stabilizer of the PA-32.
Medical and Pathological Information
The Medical Examiner District 8 in Gainesville, Florida, performed autopsies on both pilots. CAMI toxicology on the PA-32 pilot was negative for carbon monoxide and cyanide; trace ethanol (not from ingestion) was detected in blood and muscle, and diphenhydramine was found in liver (0.268 ug/ml in blood). Toxicology on the RV-6 pilot was negative for carbon monoxide, cyanide, volatiles, and tested drugs.
Tests and Research
Examination revealed evidence of the RV-6's propeller intruding into the PA-32's left wing. Laceration signatures consistent with propeller blade penetration were found on the upper left wing of the PA-32, with cut skin angle about 44 degrees. The RV-6's propeller blades had gouges consistent with impact. The collision angle was measured at about 44 degrees from the intrusion signature. Radar data indicated respective true courses of about 328 and 294 degrees, yielding a calculated collision angle of 34 degrees. Convergence angles from radar data were 70 degrees right for the RV-6 and 76 degrees left for the PA-32; measured convergence angles were about 66 degrees right and 70 degrees left, respectively.