The video clip shows the initial test-bed for the Caribou PT6 re-engineering project. The crew DID NOT takeoff with the control locks engaged. Unfortunately due to the re-routing of the engine controls and gustlock with the re-engining, it was possible for the control lock to become engaged without intentional selection by the pilots. Postmortem of the captain indicated he was still attempting to disengage the gustlock at impact. The accident delt a major blow to the aircraft development project.