What happened
On 23 February 2019, a private Beech B200 Super King Air, registration N7779V, departed Saanen (LSGK) for Amsterdam (EHAM). After an initial delay due to air traffic control constraints in Geneva, the flight crew restarted the engines. Notably, the engines were started from memory rather than using a formal checklist.
During the climb, while passing FL 150, the aircraft suffered a total electrical failure, causing all primary cockpit displays to go blank. The loss of power also caused the transponder to stop transmitting, resulting in the aircraft being marked as "lost on" radar by air traffic control. While radio contact was briefly interrupted, the pilot managed to notify controllers on the 121.5 MHz emergency frequency, stating the intention to divert to Lausanne (LSGL).
Utilizing standby instruments, iPads for navigation, and favorable weather conditions, the crew performed a visual approach and landed safely at Lausanne at 15:05 UTC. There were two slightly injured crew members, though no injuries were reported to passengers or third parties.
The investigation
SUST examined the pilot's reports, owner investigation data, and air traffic control records. The investigation focused on the electrical system, specifically the three-position IGNITION AND ENGINE START switch. Technical inspections of the aircraft's Pro Line Fusion avionics and electrical systems revealed no mechanical or electronic defects. However, the investigation found that the left-hand ignition switch had been left in the ON position after the engine start sequence.
Findings
- The primary cause of the electrical failure was that the left-hand IGNITION AND ENGINE START switch was left in the ON position, which caused the starter generator to draw excessive power and deplete the battery.
- The crew failed to follow formal checklists, instead starting the engines from memory.
- The crew did not notice the electrical system warnings or the specific DC generator annunciators during the climb.
- The availability of standby instruments (SAM/ESIS), handheld radios, and mobile navigation (iPads) significantly mitigated the risk of the incident.
Safety action
Following the incident, the aircraft owner recommended several improvements, including:
- Providing formal type rating and multi-crew coordination (CRM) training for the second pilot.
- Implementing stricter adherence to checklists to prevent errors caused by distraction or complacency.
- Updating the "Before Taxi" checklist to explicitly include a check of the ignition/start switches in the OFF position.
- Rephrasing electrical system checks to specifically verify DC voltage and load levels.