A loose bolt prevented the front landing gear from lowering on an All Nippon Airways Dash 8-400 plane that was forced to make an emergency landing at Kochi Airport on Tuesday morning (link). ANA flight 1603 from Osaka's Itami airport made an emergency landing at Kochi airport on only its main landing gear after Captain Hitoshi Imazato reported he could not lower the front gear even manually. The airplane landed on the 2,500-meter runway with its nose scraping on the bitumen surface. All 56 passengers and four crew members were unhurt. After the accident, the transport ministry issued a directive for checks on all 36 DHC8-series airplanes flying in Japan.

A bolt in the joint of an actuator arm that opens and shuts the door to the wheelwell enclosing the nose landing gear had detached and was missing. Investigators found no problems with the actual landing gear. It had simply been trapped inside a compartment that couldn't open because of the jammed door. Other components held in situ by the bolt had also fallen off, effectively jamming and immobilizing the landing gear door.

There have been three cases in the past involving Japanese DHC-8-400 aircraft that concerned problems either with stowing the nose landing gear or releasing it for landing. However Tuesday's incident was the first time that manual extension has failed to open the wheel-well doors on a DHC-8-400. A DHC-8-300 plane operated by Tobago Express failed to release its nose-gear when preparing to land at Piarco International Airport in Trinidad and Tobago in April 2005, according to a report filed with the International Civil Aviation Organization. Transport ministry officials are looking into similarities in the structure of the nose-gear compartment doors of the two marks of planes involved in the incidents.