A landing incident in Japan involving an All Nippon Airways Bombardier Dash 8 Q400 has led the manufacturer to advise all Q400 operators worldwide to inspect the aircraft's nose landing-gear door mechanism, writes Leithen Francis.

Bombardier says in the circular issued the day after the 13 March ANA incident that "operators are strongly advised to perform a visual check of the nose landing gear door mechanism on, or before, the next A check to ensure the cotter pin is present".

The advisory comes after the incident in which an ANA Q400 had to land at Kochi airport with its nose landing gear retracted. None of the 56 passengers or four crew was injured.

"Despite repeated attempts [before the landing to] use the alternate extension system, the flightcrew were unable to extend the nose landing gear," says Bombardier.

An "investigation has determined that a bolt, nut and cotter pin joining the two halves of the door over centre linkage were missing", it adds.

"This allowed the spacer to partially migrate from the hole, which may have caused contact with a fitting to which the debris shield is attached.

"It is likely that this prevented the doors from opening, stopping the nose landing gear" from deploying.

Japan's construction and transport ministry has also issued a directive. Ministry officials have told local journalists that Japanese carriers were only required to inspect the bolt on the Q400's nose landing gear door device once every 4,000h, but now the requirement will be once every 400h.

ANA group has 13 Q400s and five Q300s, while JAL group has nine Q400s, one Q300 and four Dash 8-100s.

Source: Flight International