Accident Overview
On October 20, 2013, about 1359 Pacific daylight time, a Pitts S2C (N15TA) and a Cessna 172S (N698SP) collided on the movement area at Livermore Municipal Airport (LVK), California. The Pitts, operated by Attitude Aviation, taxied into the empennage of the Cessna, operated by West Valley Flying Club. Both flights were conducted under Part 91 in visual meteorological conditions. None of the two occupants on each aircraft were injured.
Aircraft and Crews
The Cessna, manufactured in 2000, was a high-wing four-seat aircraft with tricycle landing gear, powered by a Lycoming IO-360 engine. The Pitts, manufactured in 2001, was a two-seat tandem biplane with conventional landing gear, powered by a Lycoming AEIO-540 engine. Its design limited forward visibility during taxi.
The Cessna crew comprised a certificated flight instructor (CFI) with about 965 total hours and a private pilot with about 141 hours. The Pitts crew included a CFI with approximately 10,500 hours and a private pilot with about 701 hours.
Sequence of Events
Both aircraft had landed uneventfully on Runway 25L (Cessna) and Runway 25R (Pitts). After landing, the Cessna exited onto Taxiway G south of Runway 25L and requested taxi clearance from Ground Control (GC), which was not immediately answered. About 1 minute and 15 seconds later, the Cessna crew made another call and heard noise from behind, realizing the Pitts had struck their aircraft.
The Pitts had been instructed by Local Control (LC) to cross Runway 25L on Taxiway G. The Pitts crew, having limited forward visibility, did not see the Cessna holding on Taxiway G. They taxied across the runway and collided with the Cessna's tail section.
Controller Actions and Communications
The LC cleared the Pitts to cross Runway 25L without advising of the Cessna's position. GC did not respond to the Cessna's initial taxi request. An FAA System Service Review later identified lapses in coordination and communication within the tower team, including failure to exchange information about the aircraft positions.
Damage
The Pitts' propeller made multiple contacts with the Cessna's rudder, fin, elevator, and horizontal stabilizer, causing substantial damage to the Cessna.