When the glider was carrying tanks or other vehicles, common practice was that their engines would be started in the air, usually just prior to the glider casting off from the tug; special exhaust ducts were fitted to the glider to expel exhaust fumes. The Tetrarch and M22 Locust light tanks were so large that they barely fit inside the glider, and as such their crews stayed inside the tank for the duration of the flight. Once the glider landed, the anchorages keeping the vehicle stationary would be released by the driver pulling a lanyard within his reach, and the driver would then drive the tank forward, which automatically pulled a line that operated the swing door release. Universal Carriers and other vehicles relied on one of the pilots operating the door line manually. This was achieved by the pilot sliding down the fuselage and then dropping to the ground. They would then go to each undercarriage leg and release the valves there, which would expel hydraulic fluid and allow the shock absorbers struts to deflate, and then enter the glider and operate the door release line. If the swing door was jammed after the glider had landed, it was possible for tanks to break through the unopened forward fuselage and drive straight out of the glider, which occurred in both airborne operations where Hamilcars transported tanks.