When a hole was blown open on an Alaska Airlines plane headed from Portland, Oregon to California on Friday, the depressurization was explosive. 

A 63 pound, four-foot-long panel that blew off an Alaska Airlines plane in midair was found late Sunday in a Oregon backyard. This panel provides a key clue for investigators as they try to piece together why a gaping hole opened midair on an Alaskan Airlines fight Friday afternoon. 

The flight was nearly full, with just a few empty seats, including the seats directly adjacent to the panel that blew off.  About ten minutes into its ascent the ‘door plug’ located towards the tail end of the fuselage dislocated, sucking with it several cell phones, a young boy’s shirt, and a large teddy bear. 

The NTSB’s investigation — and FAA’s airworthiness directive – affects about 171 planes worldwide which are grounded for carriers operating in U.S. territory.