What happened
The takeoff for a sightseeing flight proceeded normally until the aircraft reached approximately 500 feet agl. At that altitude, the pilot noticed the airspeed was decreasing and observed the manifold pressure drop from 36.5 inches to 23 inches. In an attempt to restore power, the pilot activated the auxiliary fuel pump but was unable to restart the engine. The pilot subsequently performed a forced landing in rough, sandy terrain.
The investigation
Postcrash examination of the Cessna T207A identified that the upper induction tube, responsible for conducting compressed turbocharger intake air to the throttle body, had separated at a rubber connecting sleeve. This separation occurred approximately 10 inches prior to the throttle body. Records indicated that Scenic Airlines maintenance personnel had installed a remanufactured zero-time engine on July 30, 1996.
Findings
The investigation determined that the separation of the upper induction tube caused the loss of compressed induction air. Additionally, the T207A Information Manual lacked instructions for abnormal operating procedures to maintain engine operation following a turbocharger failure. It was also noted that there is no current FAA requirement for aircraft manufacturers to provide information regarding proper airplane operation in the event of a loss of compressed induction air during flight in a turbocharged aircraft.