What happened
On February 2, 2017, a Tecnam P2002-JF, registration HB-KPC, was conducting a flight training mission departing from Yverdon-les-Bains (LSGY) toward Geneva (LSGG). During the initial climb, approximately three minutes after takeoff, a thick, acrid grey smoke began emanating from the instrument panel.
The instructor immediately took control of the aircraft and declared a Mayday. To mitigate the risk of smoke inhalation, the student pilot opened the canopy, allowing the smoke to dissipate. The instructor shut down the engine and cut all electrical power. The aircraft performed an emergency landing in a grassy field, eventually crossing a concrete path and coming to a stop in a soft, plowed field where the nose gear collapsed. Both occupants, an instructor and a student, escaped the aircraft without injury.
The investigation
Investigators examined the electrical system and found that the primary 50A fuse had melted. Detailed inspection of the engine compartment revealed overheating on the electrical connectors and the yellow cables connecting the alternator to the rectifier-regulator. Notably, these cables had been shortened, which placed them under mechanical tension.
Further analysis of the cockpit components showed that the safety valve of one of the two 22,000 μF capacitors had ruptured, releasing electrolyte and smoke. The investigation also noted that the electrical system's power generation was undersized for the total demand of the installed electrical consumers.