An off-duty pilot on a San Francisco-bound flight attempted to shut down the plane’s engines before being subdued Sunday. The crew said that 44-year-old Joseph Emerson, a Bay Area resident, tried to trigger the fire suppression system — which would’ve cut off fuel, electricity and hydraulic power to the engine — while sitting in the cockpit’s jumpseat. The pilots were able to subdue Emerson, who was jailed on suspicion of attempted murder. FBI investigators are still piecing together a motive.