What happened
On March 22, 1998, a Piper PA-32R-300, registration HB-PBK, was conducting a private IFR flight from Nîmes to Geneva-Cointrin. While the flight initially proceeded under visual meteorological conditions, the aircraft experienced a sudden and total electrical failure during the approach to Geneva. The pilot observed the VHF radio displays flickering and then losing power, followed by the loss of instrument lighting. In response to the emergency, the pilot transmitted a 7600 squawk code and attempted to reset the battery and alternator, but was unsuccessful.
During the final stages of the approach, the pilot attempted to deploy the landing gear using the emergency release lever. However, the pilot mistakenly pulled the lever instead of pushing it. Unsure if the gear had successfully deployed and seeking to avoid blocking the main runway, the pilot elected to land on an unlit grass runway. The aircraft touched down 44 meters before the runway threshold and slid on its belly for 225 meters. Despite the impact, the pilot and three passengers escaped without injury.
The investigation
Technical investigators determined that a broken alternator excitation cable had caused the electrical failure, which eventually depleted the battery. Post-accident inspections revealed that the battery was completely discharged, though the alternator warning light was functional when the engine was running after the crash.
Regarding the landing gear, the investigation found that the emergency release mechanism was functional but required a pushing motion rather than a pulling motion. The investigators noted that the pilot's error may have been influenced by familiarity with a different aircraft, a more recent Piper model (HB-PEJ), where the emergency gear lever is operated by pulling.
Findings
- The primary cause of the accident was a total electrical failure on board the aircraft.
- A secondary contributing factor was the pilot's incorrect manipulation of the emergency landing gear release lever.
- The decision to land on an unlit grass runway increased the risk of encountering obstacles and delayed emergency response due to the loss of visual contact by the control tower.
- The pilot failed to drain the fuel tanks during pre-flight preparations in Nîmes, a practice that, while not directly causing this specific accident, is noted as a critical safety oversight for IFR operations.