What happened
On September 8, 2013, a Tecnam P2002-JF, registration HB-KPB, departed from the grass runway at Geneva Airport for a local flight. Shortly after takeoff during the initial climb, the pilot heard an electrical short-circuit sound followed by an explosion. White, acrid smoke immediately began filling the cockpit near the floorboards.
The pilot notified air traffic control of the smoke and attempted to rejoin the traffic pattern. However, a second explosion occurred in the cockpit, significantly increasing the smoke density and obscuring the flight instruments. To mitigate the smoke, the occupants opened the sliding canopy, which allowed the fumes to be evacuated.
Noticing a grassy field to the northwest, the pilot executed an emergency landing. During the maneuver, the aircraft encountered a power line, requiring a slight course correction. The aircraft touched down in a wet field, crossed a hidden trench, and sustained damage to the nose gear and propeller. Both occupants escaped the aircraft without injury.
The investigation
The investigation focused on the electrical components located within the cockpit. Investigators examined the engine installation manual, which requires two 22,000 μF electrolytic capacitors to be connected to the regulator-rectifier to stabilize voltage. These components were found installed in the cockpit area, positioned approximately 20 cm above the right rudder pedals.
Technical analysis revealed that the wiring on the aircraft did not match the manufacturer's maintenance manual diagrams. Furthermore, the investigation found that the safety membrane on the defective capacitor was obstructed by the insulation from the positive terminal, preventing proper pressure release.
Findings
- The primary cause of the accident was a capacitor failure that led to a short circuit and subsequent smoke emission.
- The installation of the capacitors inside the passenger cabin placed occupants at risk during a failure.
- The electrical wiring was not in compliance with the manufacturer's specifications.
- The safety membrane intended to manage internal pressure in the capacitor was blocked by terminal insulation.
- A 50A fuse was found to have melted during the event.