A Bombardier DHC-8-315, JA727B operated by the Japan Coast Guard (JCG) took off from Hanamaki Airport at 13:58 local time for a training flight. The captain, who was an instructor, sat in the right seat and the trainee in the left seat for training to obtain the type rating for First Officer certification in the Japan Coast Guard. The final part of the training was a flap up landing at Sendai Airport, Japan. The captain and the trainee completed the flap up landing checklist just before the arrival at Yuriage (a visual reporting point of Sendai Airport) and the captain told the trainee that if the pitch angle (nose-up angle) exceeded 6ø, corrective control would have to be performed by pushing the control column forward. Vref (reference speed for landing) was 126 kt. The aircraft entered the traffic pattern of runway 09 and landed around 15:58. Although the trainee made the main landing gear touch down near the aiming point marking for the runway 09, he felt it took a great deal of time to lower the nose. This time the captain on the right seat pushed the control column forward since he feared a tail strike. Then the nose landing gear touched the ground with stronger impact than usual (+1.47 g). In. Both the captain and the trainee were not aware of irregularity of the aircraft in landing roll, therefore they continued taxi and the aircraft arrived at the apron at around 16:05. After the engines were shutdown, the nose landing gear was found to be damaged in post-flight inspection by the on-board mechanic. Afterward, detailed inspection was conducted, which revealed abrasion marks on the lower part of the nose landing gear, damage on components of the nose landing gear, and deformation of the forward fuselage skins of the airframe. PROBABLE CAUSES: “In this accident, it is probable that the nose of the aircraft suddenly downed and the nose landing gear strongly touched down on the ground after the main landing gear touched the ground in the landing, therefore the components of the nose landing gear were damaged and the fuselage skins of the airframe was deformed. Regarding the fact that the nose landing gear of the aircraft strongly touched the ground on the ground, it is probable that it was because that the captain who considered worry of tail contact performed the sudden and large control for moving the nose downward, when the nose-up attitude tended to be too excessive after the nose landing gear touched the ground once and the nose upped again.”