Event Sequence
An aircraft mechanic reported that one of the airplane's engines was making an unusual noise during takeoff. An air traffic controller observed that the flight used about 4,500 feet of runway before lifting off. Approximately one minute after being cleared for takeoff, the pilot communicated, "we're coming around we're losing a right engine." The controller and a witness then saw the airplane level off, sway left and right, and subsequently descend. The pilot reported he was not going to make it, and the airplane was lost from sight behind trees.
Post-Crash Examination
Examination of the airplane structure, flight controls, engines, and propellers after the crash revealed no evidence of pre-crash failure or malfunction that would have prevented operation. The landing gear and wing flaps were found in the retracted position. Both the left and right propellers were found in the low blade angle position and had similar damage patterns.
Propeller Signatures
An NTSB sound study of air traffic control communications indicated that at the time the pilot reported they were not going to make it, one propeller signature showed a rotational speed of 1,297 rpm, while another propeller signature showed a speed of 2,160 rpm.
Pilot Operating Handbook Information
The engine inoperative procedure in the Pilot Operating Handbook for the Cessna 421C specifies that for an inoperative engine, the throttle should be closed, the mixture placed in idle cut-off, and the propeller feathered. The handbook also indicates that under the accident conditions, the airplane would normally require about 2,000 feet of runway for takeoff.
Probable Cause
According to official findings, the probable cause of the accident was the failure of the pilot to shut down the right engine and feather the propeller after a reported loss of power in the engine shortly after takeoff, resulting in the airplane descending, colliding with trees, and then the ground.