Precise procedures

Published on 9 January 2008 (updated on 11 January 2008)

 


Before starting engines and at the pilot’s request, the controller communicates constraints arising from regulation of flow and possible start-up approval guaranteeing issue of clearances for ground movement and take-off within reasonable times.

In addition, he supplies the following information : runway in use, direction and speed of surface wind with significant variations, ground visibility, quantity of low cloud with altitude at their base, air temperature, altimeter setting required in order to read the altitude equal to the topographical altitude of the airfield at the highest point of the landing area (QNH), atmospheric pressure at the topographical altitude of the airfield (QFE), transition level (if necessary) and the exact time.

Before taxiing, which precedes take-off, the airfield controller confirms the runway in use and gives the parameters mentioned above if this has not already been done.

Before take-off, he again supplies the direction, speed and variations of surface wind, as well as significant weather elements. Before the aircraft leaves the airfield circuit or the control zone, he again supplies the QNH, if he is in possession of this element.

On arrival, before issuing entry clearance into the airfield circuit, the airfield controller must indicate the runway in use, direction and speed of surface wind with significant variations, the QNH and the QFE.

Finally, before landing, the airfield controller supplies direction and speed of surface wind and the latest levels of visibility.

In addition, he supplies aircraft with information on the state of the airfield by giving the following details:

- construction or maintenance works with or without material, vehicles or personnel on or near the manoeuvre area,
- uneven or damaged parts of the surface of the manoeuvre area, whether these are marked or unmarked,
- dangers linked to the presence of water, ice, snow, birds or other animals at ground level or in flight, presence of parked aircraft, wake turbulence,
- breakdown or malfunction of all or part of the radio equipment or the visual aids of the luminous marking system,
- any other information which might be deemed useful.

The airfield controller regulates all ground traffic and organises aircraft traffic in the airfield circuit. Departures are thus carried out in the order in which aircraft are ready to take off. However, the airfield controller can deviate from this order or priority in order to ensure maximum number of departures, to achieve the minimum average delay or for regulation of traffic flow. If an aircraft has not received alignment clearance, it must wait at a stop point.

Entry or movement of pedestrians and vehicles onto the manoeuvre area is also subject to authorisation and adherence to a defined path, unless a movement of vehicles and pedestrians plan is in operation. In all cases, crossing of the runway must be authorised by the control tower.
Vehicles used on airfield manoeuvre areas must generally be equipped with radio facilities and establish a two-way link with the control tower. It is always the airfield controller who issues entry clearance into the circuit as soon as air traffic permits it and this is done by indicating the characteristic entry position in the circuit. He is also the one to give the spacing to be followed according to air traffic regulations.