What happened
On September 9, 2001, during an anniversary celebration at the Reichenbach airfield, a flight of three aircraft performed a coordinated formation flight. The group consisted of a Bücker 131, a One Design DR107, and a Christen Eagle II, registration N44DD. The pilots had pre-arranged a formation flyover and a specific sequence for breaking the formation.
As the formation passed over the threshold of runway 22 at approximately 500 feet above ground level, the pilot of the One Design DR1-07 gave the command to dissolve the formation. Following the break, the pilot of the Christen Eagle II initiated a right-hand climbing turn toward Frutigen. Witnesses observed the aircraft performing a steep climb at an angle of approximately 60 degrees. However, after completing roughly 180 degrees of the turn, the aircraft's radius tightened significantly, and the plane began to lose altitude. Observers with aviation experience noted that the aircraft appeared to stall or enter a spin over the right wing.
During the descent, witnesses heard a loud noise, which was later identified as an engine idle pop, suggesting the pilot may have reduced power in an attempt to recover the aircraft. The Christen Eagle II struck treetops before the right wingtips impacted the ground, causing the aircraft to slide approximately 20 meters. The impact resulted in the destruction of the aircraft, with the right wing separating from the fuselage.
The investigation
Investigators examined the wreckage of the N44DD and found the tail section to be largely intact, with the elevators remaining functional. A check of the engine's spark plugs showed no evidence of abnormal combustion prior to the accident. The investigation also confirmed that the aircraft's weight and center of gravity were within prescribed limits, and the weight of the baggage compartment was within legal constraints.
Findings
- The pilot was properly licensed and had performed aerobatic demonstrations earlier that day.
- There were no indications of pre-existing mechanical defects or health issues affecting the pilot during the flight.
- The loss of control occurred during the execution of a climbing turn following the formation break.
- It is believed the pilot's control inputs caused the aircraft to enter an uncontrolled flight state, and the remaining altitude was insufficient to recover the plane from the resulting stall or spin.