The Vickers Viscount had just arrived from London when it was to take off again for a training flight. Takeoff was commenced at 0850 GMT. Just after lifting off, at V2, the training captain (occupying the left hand seat) wanted to simulate a no. 4 engine failure and had to do 3 steps to accomplish this: moving the no. 4 high pressure cock lever to the feather position; pulling back the throttle lever, and; pressing the feathering button. Without noticing the captain moved the no. 3 engine high pressure cock lever to the feather position and throttled the no. 4 engine back. As a consequence the aircraft banked to the right and struck the ground 250yds from the runway, cartwheeling to a stop. PROBABLE CAUSE: “The accident was due to an error by the training captain who operated no.3 high pressure cock lever instead of no.4 when simulating a failure of no.4 engine during takeoff. This resulted in the loss of all power from both starboard engines at a critical point of the takeoff.”