A piece of the fuselage that blew off an Alaska Airlines flight on Friday has been found in the backyard of a person living in a suburb of Portland in the United States. The door plug tore off the Boeing 737 Max 9 shortly after it had taken off from Portland en route to Ontario in California, depressurising the plane and forcing the pilots to make an emergency landing. Authorities said it was fortunate that the piece of fuselage had fallen out while the plane was at 16,000 feet and the 171 passengers on board were still required to be wearing seatbelts. The National Transportation Safety Board…