Accident Overview
During cruise flight, a private pilot allowed an unqualified pilot-rated passenger to manipulate the aircraft controls, including engine controls, under supervision. After receiving a descent clearance to 3,000 feet mean sea level (msl), the pilot instructed the passenger to reduce engine power to maintain target airspeed. The cockpit area microphone recorded the sound of both engines spooling down. The pilot recognized that the passenger had retarded the engine throttles past the flight idle stops into the fuel cutoff position, stating, "you went back behind the stops and we lost power."
Sequence of Events
According to air traffic control (ATC) radar track data, at the time of the dual engine shutdown, the airplane was about 18 miles southwest of the destination airport and descending through 6,700 feet msl. The pilot reported a dual loss of engine power, declared an emergency, and requested radar vectors to the destination. During approach, the cockpit voice recorder (CVR) captured a sound similar to an engine starter spooling up, but engine power was not restored. No evidence of further restart attempts was found on the CVR, which stopped recording while the airplane was still airborne with both engines inoperative on an extended base leg.
The controller instructed the pilot to go-around because the main landing gear was not extended. The airplane was observed climbing and entering a right traffic pattern for another approach. Witnesses reported that only the nose landing gear was extended during the second approach. The airplane bounced several times on the runway before entering a climbing right turn, then a nose-low, rolling descent into a residential community.
Post-Accident Examination
Postaccident examinations and testing revealed no anomalies or failures that would have precluded normal operation of the airplane. The investigation determined that the pilot had initiated a go-around during the initial approach, implying a successful restart of at least one engine. Only the left engine was operating at impact. Procedures require resetting the respective generator after an engine start to restore electrical power to the Essential Bus. The battery toggle switch was found in the Standby position at the accident site, which would have prevented the Essential Bus from receiving power, regardless of generator reset. The airplane was likely operating on the Standby Bus, precluding normal landing gear extension. The landing gear alternate extension handle was partially extended; this position would have prevented main gear extension, allowing only the nose gear to extend. The investigation concluded that a full deployment of the handle would have enabled a successful single-engine landing.
Conclusions
The private pilot's decision to allow the unqualified pilot-rated passenger to manipulate the airplane controls directly resulted in the inadvertent dual engine shutdown during cruise descent. Additionally, the pilot's inadequate response to the emergency, including failure to adhere to procedures, resulted in his inability to fully restore airplane systems and ultimately led to a loss of control.