History of Flight
On November 28, 2009, at 1101 Pacific standard time, a Piper PA-25-235 airplane, N7023Z, and a Schleicher ASW-27 glider, N127AL, collided during the landing approach at Crazy Creek Private Gliderport, Middletown, California. The airplane was operated by Calsoar, Inc., d.b.a. Crazy Creek Air Adventures, as a glider tow flight. The glider was operated by the pilot as a local personal flight. Both aircraft were operating under 14 CFR Part 91. The private pilot on board the glider and the commercial pilot on board the airplane were killed. Both aircraft were substantially damaged.
The airplane and glider departed Crazy Creek at 1056. Visual meteorological conditions prevailed, and no flight plan had been filed. Witnesses observed the airplane and glider release west of the airport at an altitude between 2,000 and 3,000 feet mean sea level (msl). The airplane then maneuvered in the vicinity of the release and turned back towards the airport. After release, the glider tracked north along an adjacent ridgeline and shortly thereafter turned southeast back towards the airport. Witnesses described gusting crosswind conditions at takeoff, with one reporting that the airplane was being "knocked around" during climb out.
According to witnesses, both aircraft entered the downwind leg of the single northwest runway about the same time, with the glider on the right downwind and the airplane on the left downwind. They continued on downwind and turned onto their respective base legs about the same time. As the aircraft turned to final, they collided. One witness reported no abrupt or evasive maneuvers prior to the collision.
The glider was equipped with a Cambridge Aero Instruments Model 302 Direct Digital Variometer. Data extraction revealed a flight track similar to witness reports. The glider climbed to a maximum GPS altitude of 2,405 feet 2 minutes after takeoff, then changed heading north, followed by a turn southeast. Two minutes later it joined the right downwind at an elevation of 1,614 feet (about 700 feet above runway level). Groundspeed during downwind increased from 78 to 83 mph. The glider then began a right turn to base leg, during which groundspeed increased to 97 mph, and it overshot the runway centerline while still perpendicular to the approach path. The last recorded position was 4 seconds later at an altitude of 1,214 feet on a heading of about 240 degrees magnetic.
Photographs taken from the Calsoar facility on the north side of the runway showed the takeoff and post-impact sequence. A post-impact image taken just after the collision displayed the airplane relatively intact, flying straight and level on a north heading. The glider was positioned to the south of the airplane, flying on an approximate runway heading. The glider's right wing appeared fragmented midspan, with the tail section fractured aft of the cabin and pointing north. The airbrakes were deployed.
Personnel Information
The airplane pilot, aged 44, held a commercial pilot certificate with ratings for airplane single-engine land, multiengine land, instrument airplane, and glider. He held a third-class medical certificate issued July 31, 2009, with no limitations or waivers. He reported 1,600 hours total pilot time on his most recent medical application.
The glider pilot, aged 63, held a private pilot certificate with ratings for airplane single-engine land and glider. Family members reported he had undergone refractive eye surgery about 10 years prior. His glider flight logbook showed 163 glider flights since March 2005, 19 from the accident airport. As of October 10, 2009, he had accumulated 851 hours total flight time.
Aircraft Information
The airplane was a low-wing type with an elevated cabin centered just above the trailing edge of the wings. It was primarily white with red and black trim on the outboard section of the right wing and along the fuselage side panels. FAA records indicated a restricted special airworthiness certificate for glider towing. The maintenance logbook showed total airframe time of 10,356 flight hours and engine tachometer time of 3,895 hours at the last 100-hour inspection (October 13, 2009). The tachometer read 3,909 hours at the accident site.
The glider was a mid-wing type. Measurements taken at the accident site indicated that while buckled into the pilot's seat, the pilot's head would have been about 8 inches forward and 5 inches above the leading edge of the wing. The wing width at the fuselage intersection was about 30 inches. The maintenance logbook showed total airframe time of 463 flight hours at the last annual inspection (October 15, 2009).
Meteorological Information
The closest aviation weather observation station was Charles M. Schulz-Sonoma County Airport, Santa Rosa, California, 22 miles southwest. A METAR at 1053 reported winds from 340 degrees at 13 knots, visibility 10 miles, clear skies, temperature 17°C, dew point -2°C, altimeter 30.01 inches of mercury. A 1054 METAR for Napa County Airport (40 miles south) reported winds from 340 degrees at 25 knots, gusting to 35 knots. A 1053 METAR for Sacramento International Airport (60 miles southeast) reported winds from 330 degrees at 25 knots, gusting to 31 knots. Witnesses at the airport stated the wind at accident time was from the north at 25 to 35 knots. Neither pilot had requested weather reporting services from Flight Service Station. The sun altitude at 1100 in Calistoga was 28.5 degrees, azimuth 164.5 degrees.
Communications
The glider was equipped with a Walter Dittel radio transceiver and a Becker Avionics transponder. The airplane was not equipped with a radio or transponder. Neither aircraft was required to be equipped with a radio or transponder. The Calsoar facility was not equipped with a radio transceiver.
Airport Information
The runway was a 2,000-foot-long, 30-foot-wide asphalt strip oriented northwest at an elevation of about 975 feet msl. It was flanked to the south by a parallel 1,400-foot msl ridgeline. According to a Calsoar representative, a left-hand traffic pattern is considered standard at the airport.
Wreckage and Impact Information
Both aircraft came to rest about 1,300 feet east of the approach end of the northwest runway at an elevation of 980 feet msl. The airplane was 40 feet north of the runway centerline; the glider was 400 feet southwest. The wreckage path began at approximately the midpoint of the two aircraft and continued along a magnetic heading of 160 degrees for about 700 feet. The debris path consisted of outboard sections of the glider's right wing and a 3-foot-long section of the airplane's right wing tip.
The airplane came to rest on its right side on a heading of about 350 degrees. The entire cabin area sustained crush damage through to the firewall. The engine remained partially attached to its mounts, upright, and canted 90 degrees to the right. The left wing remained attached at the forward spar, folded forward and parallel to the fuselage. The inboard section of the right wing remained attached to the fuselage, with crush damage along its entire leading edge, folded aft and underneath the fuselage. The right elevator and horizontal stabilizer sustained aft crush damage; the left horizontal stabilizer remained intact. Both tow cables were retracted.
The glider came to rest inverted on a heading of about 340 degrees. The left wing remained intact and attached. The inboard 9-foot section of the right wing appeared mechanically attached at the root and was cut from the fuselage by first responders. Fragments of the outboard right wing were in the wreckage path, with red lateral streak marks similar to the red paint on the airplane's right wing. A 2-foot section of the glider's right wing tip was found tangled within the leading edge of the airplane's right wing. The single main landing gear was extended. The tailcone separated from the cabin 24 inches aft of the wing trailing edge and remained partially attached by control cables. Red lateral streak marks were along the left side of the tailcone. Black smear marks similar to the airplane's main tires were on the upper surface of the glider's fuselage just aft of the canopy. An oval-shaped ground disruption, similar to the glider's canopy opening, was about 20 feet southeast of the main wreckage, containing fragmented canopy material, flight instruments, and fragments of prescription sunglasses. All sections of both aircraft were accounted for.
Medical and Pathological Information
Postmortem examinations were conducted by the Lake County Coroner's office. The cause of death for both pilots was reported as multiple traumatic injuries. Toxicological tests by the FAA Civil Aeromedical Institute revealed no carbon monoxide, cyanide, or alcohol. Naproxen was detected in the urine of the airplane pilot.
Additional Information
14 CFR 91.113(d)(2) and (3)(e) specify right-of-way rules: a glider has right-of-way over an airplane; when aircraft are approaching head-on, each pilot shall alter course to the right.