SAN JOSE, Calif. (KGO) -- With just a pull of lever and a press of a button, power and fuel can be cut to a plane's engine by fire extinguishers.
That's what was allegedly attempted by off-duty pilot Joe Emerson in an Embraer 175 cockpit during a flight from Everett, Washington to San Francisco.
A look inside a similar plane can give us an idea of how this could have gone down.
Hiller Aviation Musuem's CEO Jon Welte showed us how things look in a Boeing 737, a plane with a bigger cockpit, but similar controls.
The emergency controls for the number one and number two engines are what Emerson tried to pull during the flight, even though they are only to be used in the case of a fire.
"What I would do is, I would pull this lever up - which is hard to do," Welte said. "I've got to push this safety button down first so it can't happen by accident. When I pull this up, this disconnects the fuel flow going to the engine. This also disconnects the hydraulics and the electrical power."
Turning the lever would start the fire extinguishers and, if done for both engines, this would leave the plane with no way to fly normally.
In the Embraer 175's cockpit, these fire extinguisher controls are up top. They are within easy access to engage for a pilot sitting in the jump seat of the cockpit right between the two pilots. It's exactly where Emerson was said to be.
"The flight was full, so all the seats were occupied, but the jump seat was available," Welte said. "There are a number of airline personnel who can sit up in the jump seats of a cockpit."
That includes off-duty pilots who are often flying to destinations where they will board a plane they will pilot themselves. Emerson was scheduled to be on a flight crew in San Francisco Monday.
Thankfully, control of the aircraft was never lost and the crew was able to divert to Portland.
The mental health of Emerson has been brought into question, and Welte says airline pilots are required to undergo medical exams every six months.
"A very important part of that examination is reviewing any mental illness issues or any medications that might affect cognitive function, any psychological issues that may have arisen in the six-month interval since the last first-class medical exam," Welte said.
These are questions we may learn answers to in the future as Emerson now faces 83 counts of attempted murder.
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