It was about as tragic an accident as we have seen on Wittman Field, Oshkosh, Wisconsin... but the NTSB has started shedding some light on the circumstances that surround this accident with the attached preliminary report.

NTSB Identification: CHI06FA206A
14 CFR Part 91: General Aviation
Accident occurred Sunday, July 30, 2006 in Oshkosh, WI
Aircraft: Grumman TBM-3, registration: N420GP
Injuries: 2 Uninjured.

This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.

On July 30, 2006, at 1207 central daylight time, a Grumman TBM-3, Avenger, N420GP, operated by the Tri-State Warbird Museum, sustained minor damage when it taxied into the empennage and fuselage of an amateur-built Vans RV-6, C-FNQP. Both aircraft were taxiing for takeoff on Papa taxiway, which parallels runway 18 at the Wittman Regional Airport (OSH), Oshkosh, Wisconsin. The passenger seated in the right seat of the RV-6 was killed, but the RV-6 pilot and the pilot and passenger of the Avenger were not injured. Visual meteorological conditions prevailed at the time of the accident. The pilots and passengers of both aircraft had attended the EAA AirVenture Oshkosh 2006 air show and were departing OSH. The Avenger's destination was Clermont County Airport, Batavia, Ohio. The RV-6's destination was Gore Bay, Ontario, Canada. It is unknown if either aircraft had filed flight plans.

The RV-6 pilot reported that the RV-6 was parked on row 301 of the homebuilt aircraft parking area that was located just south of the P-1 taxiway. The RV-6 pilot reported that the airplane was pushed onto the P-1 taxiway before he started his engine. He taxied forward on the P-1 taxiway and was directed by the aircraft "marshallers" to taxi south on Papa taxiway. He reported that he was taxiing behind a green and white, high wing airplane that had TUNDRA painted on the top of the wing. He reported that a gray airplane was in front of the Tundra aircraft. The RV-6 pilot reported that he "didn't know the TBM was behind" his airplane. The RV-6 pilot reported that he was not sure if he was taxiing forward or if he was stopped when the Avenger struck the RV-6 from behind.

The Avenger pilot reported that the Avenger was parked in the Warbird parking area located at the north end of the air show display area. The Avenger pilot started the engine and let the engine warm up for about five minutes before he began to taxi. He taxied the airplane south toward the P-1 taxiway. He observed the aircraft marshaller clear him to begin taxiing on Papa taxiway. The Avenger pilot reported that the airplane in front of the Avenger was a green and white, high wing airplane with TUNDRA written on top of the wing. He reported that he taxied at a very slow speed with the propeller speed set about 800 RPM. He reported that the Avenger had no mechanical defects and that the brakes were good. He reported that the relatively narrow width of the taxiway prevented a large angular change from the taxiway centerline. He reported he made "shallow S-turns within the confines of the taxiway width." The Avenger pilot reported that he observed the Tundra pilot taxi off the right side of the taxiway for some unknown reason. The Avenger pilot reported that he spotted the airplane that was in front of the Tundra airplane, and he stated that he had "100 yards of free pavement" in front of the Avenger. The Avenger pilot reported that when he heard the impact and saw debris flying, he shut down the engine. He reported that he never saw the airplane that he hit while he was taxiing.

The pilot of a Lancair airplane reported that he followed the Avenger while taxiing on Papa taxiway and he observed the Avenger taxi into the RV-6. The Lancair pilot reported that his airplane was parked in the homebuilt aircraft parking area near the Lancair airplane exhibit area located just south of the P-1 taxiway. He reported that about six aircraft marshallers helped push his Lancair into a position near the Papa taxiway so that he could start his engine. He started his engine and was ready to taxi onto the Papa taxiway. One of the aircraft marshallers motioned to him that he was cleared to taxi onto Papa taxiway, since there was adequate separation from the next airplane. Instead, the Lancair pilot waited because the Avenger was approaching and he did not want to be in front of the Avenger while taxiing. After the Avenger passed, the Lancair pilot taxied onto Papa taxiway. He followed the Avenger at a distance so that he could remain clear of the Avenger's propeller blast. The Lancair pilot reported that it was "stop and go" traffic on the taxiway because of the number of airplanes taxiing for takeoff. The Lancair pilot reported that the Avenger pilot did not make any "S-turns" while taxiing, but instead, taxied straight ahead. The Lancair pilot reported that "all of a sudden" he observed black smoke and debris "flying everywhere" as the Avenger hit the RV-6. The Lancair pilot reported that there were no wing-walkers or aircraft marshallers next to the Avenger while it was taxiing on Papa taxiway.

A witness reported that he observed the Avenger taxi from the Warbird parking area to the P-1 taxiway and on Papa taxiway. The witness reported that he was walking in the same direction as the Avenger was taxiing, so the witness was focused on watching the Avenger. The witness reported that the Avenger was moving "very slowly and deliberately." He reported that the Avenger did not make any S-turns while it taxied on Papa taxiway. He reported that there were no wing-walkers for the Avenger while it taxied on Papa taxiway.

Another witness reported that she saw the Avenger do one S-turn while it was on Papa taxiway. She reported that she was observing airplanes taxi toward "Tower Road taxiway." She reported that there were about 8 - 10 airplanes, including a blue B-25 warbird, in front of the Avenger. She reported she observed the Avenger angled toward the side of the taxiway when it was "further down" the taxiway, but she did not know if the Avenger was doing S-turns at the time of the accident.

One of EAA's video production team was doing a video shoot of the Papa taxiway as the dissimilar aircraft were taxing south toward Tower Road taxiway where they turned toward the runway for a "mid-field departure." The video operator was located about 40 feet south of the Tower Road taxiway. Once the aircraft reached Tower Road taxiway, an aircraft marshaller would clear the aircraft to turn left to taxi toward runway 18 where the aircraft would wait for an ATC clearance for takeoff.

The video indicated that numerous aircraft were in line on Papa taxiway at the Tower Road taxiway. The video showed that the aircraft in front of the Avenger, before the impact occurred, included the accident RV-6, a green and white high wing airplane (Tundra), a gray RV-6, a red and white Cessna 150, a Glasair, a RV-6, a L-39 jet, and a blue B-25 warbird. The video showed the Tundra in front of the accident RV-6 and just behind the gray RV-6. The video showed the Tundra taxiing off the right side of Papa taxiway. The video showed that after the Tundra taxied off the taxiway, the Avenger was in a slight turn to the right and then turned back to the centerline within about 17 seconds after the Tundra taxied off the taxiway. The Avenger impacted the RV-6 about 1 minute 21 seconds after the Tundra taxied off Papa taxiway. The Avenger was the fifth airplane from Tower Road taxiway at the time of the accident. The video indicated that the Avenger was taxiing straight ahead for about 9 - 10 seconds prior to the time of impact and was not making a S-turn. The video indicated that the Avenger pilot was looking forward over the nose of the Avenger as it was taxiing forward prior to impact with the RV-6.

The length of Papa taxiway from the P-1 taxiway to the Tower Road taxiway is 1,500 feet. The accident occurred about 320 feet north of the Tower Road taxiway. The width of the taxiway is 35 feet. The width of the Avenger's main landing gear measured from the outside of the tires is about 12 feet.

An EAA official reported that the aircraft taxiing on Papa taxiway between the P-1 taxiway and Tower Road taxiway are not controlled by ATC ground control or by EAA marshallers.

FMI: www.ntsb.gov