Alaska Airlines Accident Could Have Been Much Worse, Investigator Says

PORTLAND, Ore.—A federal probe into Friday’s Alaska Airlines flight has started with a focus on the door plug—still missing—that violently blew off the plane in midair, leaving a gaping hole in its side.

Jennifer Homendy, chair of the National Transportation Safety Board, examined the stricken Boeing 737 MAX 9 jet after she arrived in Portland, Ore., on Saturday afternoon. She described a ghostly scene inside the cabin with seat backs missing and with clothing scattered around.