What happened
During the initial climb phase following takeoff, the pilot observed a partial reduction in power from the right engine. While attempting to maintain performance by increasing throttle to full power on both engines, the crew noted an abnormally high fuel flow reading for the right powerplant. In an attempt to rectify what was perceived as an engine flooding issue, the pilot toggled the boost pump switch from high to off and back again, and subsequently attempted to reduce fuel flow by leaning the mixture; however, these actions failed to resolve the imbalance.
As the pilot attempted to troubleshoot the malfunction while remaining within the traffic pattern, the aircraft was unable to maintain its altitude. The flight path transitioned into a downwind turn, eventually resulting in a wheels-up landing into a patch of small trees located roughly half a mile short of runway 24. Despite the impact with vegetation, all nine occupants successfully exited the aircraft type without sustaining any injuries.
Findings
Post-accident inspections of the right engine identified that the spark plugs were fouled with soot and saturated with fuel. Investigators discovered that the #5 fuel nozzle had been cross-threaded and was dislodged from its position during the collision with the trees. An investigation into the fuel system revealed that a fuel pressure sensing switch failed to detect operating pressure above 6 psi during an initial test, which likely caused the excessive fuel flow condition. Additionally, findings indicated that improper use of powerplant controls and emergency procedures contributed to the event.