An off-duty Alaska Airlines pilot riding in a cockpit jump seat on a regional flight was arrested on suspicion of attempted murder after he allegedly tried to disable the aircraft’s engines during a flight. 

Alaska Flight 2059, operated by Horizon Air, was diverted Sunday evening to Portland, Ore., after the off-duty pilot “unsuccessfully attempted to disrupt the operation of the engines,” during a flight from Seattle Paine Field International Airport in Everett, Wash., to San Francisco, according to Alaska Air Group, the parent of both Horizon and Alaska Airlines.