What happened
On August 28, 2004, a Cessna 337C, registration I-ATAR, was performing a flight from Bastia, France, to Bresso, Italy, carrying a pilot and one passenger. After completing an instrument approach to Milan Linate and performing a low pass, the pilot transitioned to VFR flight toward Bresso.
At approximately 16:55 UTC, the pilot reported engine problems and declared an emergency, stating that the engines had failed. The aircraft was descending through 500 feet when it struck tree branches near a wheat field in the municipality of Buccinaslu, approximately 6 nautical miles southwest of Milan Linate. The aircraft struck the ground and was destroyed, though the impact caused only minor damage to the field.
The investigation
The ANSV investigation focused on the aircraft's fuel system and the pilot's flight management. Investigators examined the wreckage and found that the fuel lines leading from the pumps to the injectors contained no fuel. While the auxiliary tanks were found to be nearly full, containing approximately 120 liters of fuel, the main tanks had been depleted.
The investigation also reviewed the pilot's training and the aircraft's flight manual. It was noted that the pilot's experience was primarily on single-engine aircraft, such as the Cessna 172, which features a significantly different fuel system. Furthermore, the investigation found that the flight manual's instructions regarding the use of auxiliary tanks were fragmented and potentially confusing. The pilot's type-rating examination was also noted to have been conducted using questions prepared by the pilot himself.
Findings
- The primary cause of the accident was the failure to follow proper procedures for utilizing auxiliary fuel tanks, which led to the exhaustion of fuel in the main tanks.
- The pilot failed to plan the flight consumption in a manner consistent with the requirements for managing auxiliary fuel.
- The aircraft's flight manual contained fragmented and unclear information regarding the management of the fuel system.
- The pilot's training on this specific aircraft type was insufficient to ensure proper management of the complex fuel system during all flight phases.