NTSB: Autopilot Trouble Reported Before Double-Fatal Orlando Plane Crash

In last moments before his plane nose-dived into an Orlando lake, Robert Stimmel frantically asked an air-traffic controller for help.

His autopilot won't disengage. He's heading into classified airspace.

The plane started porpoising, using full power going up and then down.

In a last-ditch effort, an unidentified voice on the radio tells Stimmel to flip his master power switch.

That'll shut off the power and radio, and hopefully restart the autopilot, the man told Stimmel.

His radio went quiet for about 30 seconds and then Stimmel is heard calling for an Orlando controller.

He's cut short, though, with an inaudible last word.

The first 911 call came in about a minute later.

Those last minutes are detailed in a report released this week by the National Transportation Safety Board, which is investigating the Nov. 20 crash.

Stimmel was piloting the six-passenger Beechcraft Bonanza with his new wife, Maria Stimmel, by his side when they crashed into Clear Lake off Rio Grande Avenue in south Orlando. Both were killed.

The couple, from Washington, had been in the air for less than 5 minutes before reporting the autopilot trouble.

An aircraft controller told Stimmel to take his airplane at or below 1,500 feet. He advised he was at 2,000 feet and would descend, the NTSB report states.

While lowering, the air-traffic controller warned Stimmel that he was heading into classified air space. He needed to turn, but Stimmel said he was having trouble getting his autopilot to disengage.

"Listen, I think we need to put this thing on the ground, I don't know what's going on," he's heard telling the controller.

Stimmel is told he can return to Orlando Executive Airport. They cleared a runway and shut the airport down for him to land, according to the report.

He is then heard asking the controller for help.

"I have to use full force. Does anybody have any ideas on what I can do to shut off this autopilot?" he says.

An unidentified voice responds on the radio telling him to pull the circuit breaker, according to the NTSB report.

"We pulled the circuit breaker, but it's just going up and then it's going down," he says, sounding panicked. "It's going up and down. We pulled the circuit breaker but just keeps porpoising up and down."

The unidentified voice then tells Stimmel to cut all electrical power to the plane for 30 seconds. The engine will stay running, the voice says, but the radio and power will cut out.

Stimmel sounds confused as he asks what exactly to turn off.

"I have a Bonanza A36 and I'm relatively new to it," he says.

The communication stops shortly after that.

Witnesses told NTSB investigators that they saw the plane turn and then nose-dive into the lake. It crashed about four miles from Orlando Executive Airport, according to the report.

Federal Aviation Administration records show Stimmel had held his private pilot license since June 2010.

sallen@orlandosentinel.com