What happened
On November 1, 2015, a Piper PA-28-181, registration HB-PJP, departed from Neuchâtel (LSGN) for a private flight. While cruising at approximately 4,600 ft AMSL over the western sector of the Payerne military airfield (LSMP), the pilot noticed smoke entering the cockpit accompanied by a strong odor of burning plastic. The source of the smoke appeared to be located beneath the seats. In response to the developing situation, the pilot executed a precautionary landing at Payerne, touching down safely at 15:09 local time.
The investigation
Following the incident, technical specialists and investigators from the SESE examined the aircraft to identify the source of the smoke. The inspection revealed that the potentiometer knob for the "NAV LIGHT and RAD LIGHT" controls was in the engaged position. Upon further examination of the electrical wiring, investigators found that a multi-connector and its associated wiring showed visible burn marks. This connector, located behind the instrument panel, is a central component of the navigation and instrument lighting systems.
Beyond the immediate electrical failure, the investigation uncovered several significant discrepancies regarding the aircraft's regulatory status. The aircraft's Airworthiness Review Certificate (ARC) had expired 68 days prior to the incident. Additionally, the technical documentation, including the Pilot Operating Handbook (POH), was not up to date, and several required certificates were missing. The investigation also noted that cockpit placards and checklists were not in English, and the aircraft lacked the required metal identification plate for Swiss registration.
Findings
- The primary cause of the smoke was an electrical malfunction involving a burnt multi-connector within the lighting circuit.
- The aircraft's Airworthiness Review Certificate (ARC) was invalid at the time of the flight.
- Technical records and the POH were incomplete or not updated.
- There were inconsistencies between the cockpit placards and the official POH.
- The aircraft lacked the mandatory metal registration plate required by Swiss regulations.
Safety action
Following the investigation, the Federal Office of Civil Aviation (FOCA) implemented several measures to improve oversight of imported aircraft. These include conducting technical inspections to renew expired ARCs, notifying operators three months before an ARC expires, and actively monitoring expired certificates. Furthermore, FOCA has reserved the right to perform additional airworthiness monitoring (ACAM) on aircraft imported from other EASA member states based on risk assessments of their technical documentation.