Raytheon Aircraft Company G36 N618MW accident near Hawthorne, California

Probable cause

The pilot’s failure to maintain an adequate airspeed during a go-around, which resulted in a loss of airplane control. Contributing to the accident was the inadvertent activation of the fuel boost pump during the attempted go-around.

NTSB analysis

While on final approach during the accident landing, the pilot informed air traffic control tower personnel that he was going to perform a go-around but gave no explanation for the maneuver. Witnesses observed the airplane climbing westbound ”belching” black smoke, then the engine stopped. When the airplane was about midfield, they saw it turn left and then back to the right and descend out of sight. The airplane impacted the roof and a vertical wall of a five-story building before coming to rest in an adjacent parking lot.

Postaccident examination of the engine’s spark plugs and cylinders indicated that the engine was running with an overly rich fuel/air mixture, which was also evident from the witness statements of the black exhaust emanating from the airplane. The electric fuel boost pump switch is located next to the landing gear selection handle. According to the G36 Pilot Operating Handbook, the engine’s electric boost pump provides pressure for starting and emergency operation only. The handbook cautions that use of the electric boost pump during normal operations can result in an overly rich fuel/air mixture, possibly flooding the engine. If either pilot inadvertently activated the fuel boost pump while attempting to retract the landing gear during the go-around, it could have resulted in a temporarily rich fuel/air mixture, reducing the available engine power and possibly distracting the pilots during the go-around. Although, the examination revealed that the electric fuel boost pump system switch was in the “OFF” position and that the pump was not operating at the time of impact, it is possible that the pilots recognized that the electric fuel boost pump system was on during the go-around and switched it off before the crash. The position of the switch and the reduced engine power likely distracted the pilot, who did not maintain adequate airspeed during the go-around, which resulted in a loss of control.

Text from the NTSB. Open the NTSB docket for WPR09FA347 for the full record.