abnormal with smells, with smoke, anything of that nature, particularly when you're halfway across the ocean, it's of great deal of concern and it has to be responded to immediately. >> reporter: in order to make a last-minute landing on the island, aviation experts say the pilot would have had to dump fuel before reaching the runway. passengers became more alarmed approaching the island because of turbulence. >> after that 40-foot drop it got really silent in the cabin. people prayed. we all prayed. i prayed. there's nothing wrong with that. >> reporter: midway island known for the battle of midway in world war ii was once the home of a naval air station. recently used for other emergency landings including a delta airline flight which touched down there in 2011. united airlines says it's still investigating the mechanical issue that forced the pilot to divert. >> this smell would be a smell from a spark, a wire that had come loose, a wire that had arced against the airframe of