Radar Separation

16.32Separation Minima. Radar provides the ATCO with fairly accurate position information for an aircraft under his/her control. Problems associated with radar include: slant range display, target discrimination and loss of contact close to the radar overhead. These ‘errors’ must be handled in the same manner that other positional errors are: by the addition of ‘buffer’ allowances. The errors are worse for long range radars used in area control but must still be considered for terminal radars covering a much smaller area. The basic radar separation standard is 5 NM. This means that where two aircraft identified on radar are at the same level, they are not permitted to approach closer than 5 NM to each other on the radar display.

16.33Reduced Radar Separation. When approved by the authority and in specific circumstances, the radar separation standard (5 NM) may be reduced. The following describe these specific occasions:

•Radar capabilities. When radar capabilities so permit at a given location, the radar separation standard may be reduced to 3 NM.

•ILS Localizer. Where two (or more) aircraft are established on the same ILS localizer

•Simultaneous Parallel Approaches (Mode 2 - Dependent). During Mode 2 parallel runway operations radar separation is applied. Between aircraft on adjacent localizer courses the separation standard may be reduced to 2 NM between contacts on the radar display.

Procedural Wake Turbulence Separation

Separation 16

Separation 16

pressure area above the wing. It spirals ‘in board’ towards the fuselage. The vortex exists at the level of the generating aircraft and to an altitude not exceeding 1000 ft below the generating aircraft. Where the following aircraft is within this airspace, wake turbulence separation must be applied.

16.35 Wake Turbulence Categories. Aircraft are categorized by maximum take-off mass (MTOM) to relate to the severity of the wake vortices generated. There are three categories as follows:

•Heavy - all aircraft types with MTOM equal to 136 000 kg or more

•Medium - aircraft types with MTOM less than 136 000 kg but more than 7000 kg

•Light - aircraft types with MTOM of 7000 kg or less

Note: MTOM is stated on the Certificate of Airworthiness for the aircraft.

16.36Separation Minima. The following procedural (non-radar) wake turbulence separation is applied. Note the criteria are only applicable where the following aircraft is ‘lighter’ than the preceding aircraft.

16.37Arriving Aircraft. Timed approaches:

•Medium behind a heavy - 2 minutes

•Light behind a medium or heavy - 3 minutes

16.38 Departing Aircraft. For a light or medium taking off behind a heavy, or a light behind a medium, a minimum of 2 minutes is applied when they are using:

•The same runway.

•Parallel runways separated by less then 760 m.

•Crossing runways if the projected flight paths cross at the same altitude or within 1000 ft below the heavier.

•Parallel runways separated by 760 m or more if the projected flight paths cross at the same altitude or within 1000 ft below the heavier.

Separation 16

Figure 16.17 Intermediate take-off

Note: Separation is increased to 3 minutes where a light or medium is taking off behind a heavy (or light behind a medium) from an intermediate part of the same runway or an intermediate point on parallel runways.

16.39 Displaced Landing Threshold. A separation of 2 minutes is applied between light or medium and heavy (or between light and medium) when operating on a runway with a displaced threshold when:

•A departing light or medium follows a heavy arriving, or a departing light follows a medium arriving, or

•An arriving light or medium follows a heavy departing, or an arriving light follows a medium departing, if the projected flight paths are expected to cross.

16.40 Opposite Direction. A separation of 2 minutes is applied between a light or medium and a heavy, or between a light and a medium, when the heavier aircraft is making a low or missed approach and the lighter aircraft is using an opposite direction runway for take-off, or is landing on the same runway in the opposite direction, or on a parallel opposite direction runway separated by less than 760 m.