What happened
During an Experimental Aircraft Association (EAA) airshow, a Boeing 72 2Q6 was cleared to back-taxi down runway 9 for an immediate takeoff. The crew was instructed to expedite their departure because a T-34 aircraft was on final approach, approximately three miles out. As the Boeing 727 reached a speed of approximately 80 to 100 knots after setting takeoff rated thrust, the captain observed a Lancair 360 approaching on the runway.
The pilot of the Lancair 360 had been taxiing toward runway 9 under the direction of an airshow flagman (ground marshaller). The flagman had previously instructed the pilot to taxi quickly down the runway to depart before the field closed at 1500, suggesting the aircraft taxi onto the grass in front of waiting warbirds. Although the flagman coordinated via radio to ensure the grass area was clear, the Lancair 360 straightened out and taxied the final 30 feet of runway 31, turning westbound along the edge of runway 9.
The pilot of the Lancair 360 reported that due to significant noise and commotion on the runway, he failed to recognize the Boeing 727 back-taxiing. He also noted that while monitoring the runway frequency, he did not hear any communications regarding the 727's position. Upon spotting the larger aircraft, the pilot of the Lancair 360 attempted to move to the far left side of the runway to provide clearance.
The flagman broadcast an "alert, alert, alert" message over the Flightline Operations network to notify the tower of the aircraft on runway 9. As the Boeing 727 began its takeoff roll, it encountered the Lancair 360. The captain executed an aborted takeoff, utilizing reverse thrust and heavy braking to maneuver the aircraft to the left. The right wingtip of the Boeing 727 passed directly over the top of the Lancair 360, but no contact occurred. Both aircraft were not damaged following the incident.