CONCORDE - SPECIAL ARRANGEMENTS

Few people, even if they are only remotely interested in aviation, can fail to be excited by their first sight of Concorde. The western world’s first supersonic transport aircraft has caught the imagination of the ordinary public like no other, yet its commercial operation has become routine in the space of a few years. Thirty-six British Airways scheduled passenger flights cross the Atlantic every week, 28 of them to and from New York, the remainder to and from Washington and Barbados. In addition, ‘pleasure’ flights on Concords are being arranged more and more frequently , perhaps to European or Middle East destinations, or to the Bay of Biscay for a short supersonic trip before returning to London. Air France Scheduled Concorde Services to the United States also operate daily, routing through UK airspace under the control of the London ATCC.

Although Concorde is designed for supersonic flight, it is restricted to normal subsonic speeds and flight levels while over land, to avoid possible disturbance to persons and property on the ground. Of course the essential advantage Concorde has over conventional aircraft is the reduction, by roughly 50% in travelling time between international airports.

Also, the special characteristics of Concorde make it unique in air traffic controls terms. The aircraft has an optimum operating profile-which, if not followed, can result in a dramatic loss of economy. Control decisions, especially during the climb and acceleration phases, are critical to the efficient performance of the flight. The fuel calculations start before the aircraft leaves the airport gate - the fuel for ground running must be used up while the aircraft is still on the ground: from start-up to take-off must not be greater than l5 min, and Concorde will often ‘jump the queue’ ahead of other aircraft waiting for departure.

After take-off Concorde climbs at between 3,000 and 6,000 ft/min, up to 28,000 ft at 95% of the speed of sound during the subsonic phase. Other flights may will be overtaken due to the higher speed and this has to be taken into consideration by the controller so as to permit, as far as possible, a climb which avoids deviations from track.

When the aircraft accelerates and climbs to supersonic flight, reheat is applied and fuel consumption is especially high. During this phase an uninterrupted climb is essential for optimum performance; controllers need to plan for the absolute minimum of changes to the aircraft’s track.

A similar situation applies during the descent and deceleration phase towards the end of the flight. Here again, control instructions for changes in track or descent profile will increase fuel consumption considerably. Where there are likely to be delays in landing at the destination airport, the usual procedure is for aircraft to enter a holding pattern, quite close to the airport, at low level. For Concords, this is a routine which consumes excessive fuel, and low level holds are to be avoided whenever possible.