The DC-3 left for a training flight at Poitiers; on board were a pilot-in-command/instructor, a flight mechanic, four trainee pilots and two passengers. With a trainee pilot at the controls, a break-through and landing on one engine was carried out. The landing was discontinued because the gear failed to lock down too late. When power was re-applied the DC-3 veered the right and crashed into the buildings of an army munitions dump. PROBABLE CAUSE: “The accident was due to the successive appearance of two incidents during a training exercise: slowness of the landing gear to extend; failure of the right engine to pick up power. The crew which included a pilot under training and a mechanic with limited experience, did not properly co-ordinate their actions. The instructor, because of his position in the cockpit, was unable to assist.”