Federal safety investigators say they haven’t yet determined what caused an experienced pilot to lose control of his private airplane and crash into an Orlando lake Nov. 20, but evidence so far indicates he was experiencing problems with the plane’s autopilot system.
Robert Stimmel, 61, and his wife Maria Stimmel, 45, were killed when the six-passenger Beechcraft Bonanza flew out of control and nose-dived into Clear Lake about 12 minutes after taking off from Orlando Executive Airport at 11:27 a.m.
The couple, residents of Washington State, was bound for Gainesville Municipal Airport in Texas.
Mr. Stimmel frantically radioed air-traffic controllers for help, saying his autopilot wouldn’t disengage and it was sending his plane into classified airspace. The airplane flew up to an altitude 500 feet higher than it was supposed to be using full power.
“Listen, I think we need to put this thing on the ground. I don’t know what’s going on,” Mr. Stimmel told the controller. Orlando Executive Airport cleared a runway for him.
The airplane then dropped and continued flying in an erratic up-and-down motion. Mr. Stimmel told controllers he was not in control of the aircraft.
“I have to use full force. Does anybody have any ideas on what I can do to shut off this autopilot?” he asked.
According to the National Transportation Safety Board (NTSB), an “unknown voice” instructed Mr. Stimmel to pull the circuit breaker — a last-ditch effort to reset the autopilot. The aircraft’s radio then fell quiet for several seconds before Mr. Stimmel is heard calling for an Orlando controller.
“We pulled the circuit breaker, but it’s just going up and then it’s going down,” he told air-traffic controllers, sounding panicked. “It’s going up and down. We pulled the circuit breaker but just keeps porpoising up and down.”
His pleas for help were then cut short and the first 911 call was made about a minute later. Witnesses say that the airplane banked and nosedived into the lake, about four miles from the airport.
The NTSB said the accident remains under investigation. The Board usually takes up to a year to close an investigation and issue a final report.