What happened
A Cessna TR182 was positioned on an easterly heading at the first run-up marker, where it had been conducting pre-takeoff checks for approximately two minutes. At the same time, a pilot in the rear seat of a Piper J3 was taxiing north toward the run-up area to perform checks prior to an annual inspection.
As the Piper J3 proceeded north, other aircraft were present in the vicinity: parked aircraft were on the left side of the Piper, a Cherokee was approaching from the 1 o'clock position, and a Twin Otter was approaching from the 4 o'clock position. Upon nearing his intended run-up location, the pilot of the Piper J3 observed the Cessna TR182.
The pilot attempted to avoid the collision by shutting down the engine and applying the brakes, but the aircraft could not stop in time. The right wing of the Piper J3 scraped the underside of the Cessna's wing, and the Piper's propeller struck the Cessna's right horizontal stabilizer and elevator. The impact caused substantial damage to the Cessna's tail surfaces, while the Piper J3 sustained minor damage to its propeller.
Findings
The pilot of the Piper J3 stated that he had performed a thorough scan of the run-up area prior to the collision but failed to see the stationary Cessna. The pilot suggested the aircraft may have been obscured by a blind spot or had blended into the background.