Aviation inspectors found a key part missing from a Boeing jetliner during an emergency inspection prompted by the explosion of a similar plane on Aug. 20 in Okinawa, officials said Friday.

A washer was missing from a wing slat component of a Boeing 737-700 owned by Air Nippon, an oversight that could lead to a bolt coming loose, said transport ministry official Atsushi Shimamura.

On Aug. 20, a China Airlines Boeing 737-800 exploded in a fireball shortly after landing at Naha airport. All 157 passengers and eight crew members had evacuated safely onto the tarmac just seconds before the inferno.