What happened
On August 16, 2002, a Beechcraft BE A60, registration HB-GFA, was performing a flight from Nice, France, to Locarno, Switzerland. While flying under IFR flight rules, the pilot contacted Milan ACC to declare an emergency due to engine failure, requesting an emergency landing at Milan Malpensa Airport.
During the descent, the aircraft began losing altitude rapidly. Radar tracking showed the aircraft descending at an average rate of 1,500 feet per minute, reaching a final altitude of approximately 1,200 feet before disappearing from radar. The aircraft struck the ground near the SP 2/26 provincial road in Jerago Con Orago at a near-vertical angle. The impact resulted in four fatalities, as all occupants—the pilot and three passengers—perished in the crash.
The investigation
The ANSV investigation examined the wreckage, engine components, and radar data. Investigators found that the right engine had stopped prior to impact, while the left engine was still rotating at the moment of collision. Analysis of the cylinder heads, pistons, and spark plugs revealed that both engines had been operating with an extremely lean fuel mixture for several minutes, which likely led to the engine failure.
Technical examination of the cockpit controls showed that the mixture control for the right engine was pulled completely back, while the other controls were in the forward position. Furthermore, the pilot had failed to set the right propeller to the feather position, which increased aerodynamic drag. Radar and witness accounts suggested the pilot attempted a sharp pitch-up maneuver to avoid trees in the flight path, which likely induced a stall.
Findings
- The primary cause of the accident was a low-altitude stall that led to a loss of control and a vertical impact with the ground.
- The stall was likely triggered by an aggressive pitch-up maneuver performed by the pilot in an attempt to clear tall trees.
- Improper management of the fuel mixture controls contributed to the event; the pilot failed to enrich the mixture during descent, causing the right engine to fail and the left engine to run extremely lean before eventually flooding when the mixture was moved forward.
- Contributing factors included the failure to feather the right propeller and the potential for an emotional block, which may have hindered the pilot's ability to execute effective corrective actions during the emergency.