Incident Overview
On the day of the accident, the aircrew of a Gates Learjet 35A, registration N873LP, was conducting an arrival at Auburn Airport. The crew canceled their IFR clearance and contacted the Auburn unicom. They entered the traffic pattern to land on runway 18. According to the unicom operator, the Learjet crew reported their position on each leg of the traffic pattern.
At approximately the same time, the pilot of an unregistered, experimental Challenger II was in the traffic pattern for runway 10. The two runways intersected at their approach ends. The Challenger II, a two-place version of an ultralight vehicle, was not equipped with a radio, and the unicom operator was unaware of its presence in the traffic pattern.
Collision Details
Just before landing, the two aircraft collided as they were crossing over the intersection and subsequently crashed on the airport. The Learjet pilot stated that neither he nor his copilot had seen any other traffic at the airport. No evidence was found that either crew had taken evasive action.
An examination of the crash site revealed that the collision occurred approximately 50 feet above the intersection. One pilot on board the Learjet was killed, while six other occupants were injured. The pilot of the Challenger II was also killed.
Probable Cause
The official probable cause findings are divided into two occurrences. Occurrence #1: midair collision during approach - VFR pattern - final approach. Contributing factors include: control tower unavailable; radio communications not possible for the pilot of the other aircraft; inadequate visual lookout by the pilot in command of the Learjet; and inadequate visual lookout by the pilot of the other aircraft. Occurrence #2: in-flight collision with terrain/water during uncontrolled descent.