From Mainichi News (Japanese newspaper) web site today:
Dislodged bolt behind ANA plane's belly-landing
A dislodged bolt was behind Tuesday's belly-landing of an All Nippon Airways plane at Kochi Airport, government inspectors advised.
Inspectors from the Ministry of Land, Infrastructure and Transport's Aircraft and Railway Accident Investigation Committee visited Kochi Airport to inspect the ANA Bombardier DHC8-Q400 that was involved in Tuesday's accident.
A bolt locking the arm that operates the front-landing gear door had fallen off, causing the door to malfunction.
The inspectors will reportedly continue investigating the plane.
Investigations said that because the bolt had been dislodged, a steel ring that covers it was moved and blocked the front-landing gear's door from opening.
A report in the same paper described how a passenger on one of the platforms at Tokyo station was hit on the head by a bolt falling off the roof yesterday. Does something happen to bolts in Japan in Spring?