Helicopter flight controls blades collectively ("i.e.," all at the same time) and independent of their position. Therefore, if a collective input is made, all the blades change equally, and as a result, the helicopter increases or decreases its total lift derived from the rotor. In level flight this would cause a climb or descent, while with the helicopter pitched forward an increase in total lift would produce an acceleration together with a given amount of ascent. The collective pitch control in a Boeing CH-47 Chinook is called a "thrust control", but serves the same purpose, except that it controls two rotor systems, applying
Boeing Chinook (UK variants) due to its remarkable service record. It has seen action in every major operation involving the RAF in the helicopter's 25-year service life, including the Falkland Islands, Lebanon, Germany, Northern Ireland, Iraq, and Afghanistan. During the Falklands War, Chinooks were deployed by both the British and Argentinian forces. In April 1982, five Chinooks were loaded aboard the container ship MV "Atlantic Conveyor" bound for the Falkland Islands, to support the British operations. On 25 May 1982, the Chinook "Bravo November" was sent to pick up freight from HMS "Glasgow". While the helicopter was airborne, the "Atlantic Conveyor" was attacked by