VV Approach™ Learning Outcome

VV Approach™ teaches the sequencing of high-speed jet and prop-jet aircraft onto a runway of any alignment. That is the most difficult task in Air Traffic Control and the skill to do it one of the most valuable in the aviation industry. The capacity of an airport is ultimately limited by the number of aircraft that can use a runway in a given time, and that is determined by the accuracy with which the Radar Approach Controller[s] can space landings. Each runway has an ideal landing spacing, which is primarily set by the availability and configuration of taxiways via which landing aircraft can manoeuvre clear of the runway to make it available to the next in sequence.

The generally-accepted ideal landing spacing between high-performance aircraft is two minutes. This spacing provides adequate time for the first aircraft of a pair to vacate the runway comfortably in time for the following one to land. It also allows one departing aircraft to take off between each pair of arrivals, which is very efficient use of a runway. The two minutes can be reduced when Wake Turbulence separation between successive aircraft on the approach permits it, which usually means aircraft of Heavy weight category. Between these aircraft a spacing of one and half minutes is commonly used worldwide on runways with arrivals only. Conversely, spacing in excess of two minutes is frequently required, for a number of reasons: adverse weather, strong winds, unserviceable taxiways, the need to accommodate more departures than arrivals etc.

The Radar Approach Controller must be able to sequence aircraft very accurately for any specified spacing at touchdown. Variation from the ideal two minutes can be ongoing - weather, strong winds, or transient - varying numbers of departures between arrivals. Rather than specifying a time spacing between landings, which would be very difficult to calculate and apply, it is generally expressed as a spacing distance at touchdown, as judged by the surveillance system (usually radar). At typical jet speeds two minutes is very close to five nautical miles: when an aircraft touches down the one following it is five miles from the runway threshold, usually on the extended centreline and in landing configuration. This is commonly referred to as a 'five-mile sequence'. For a one-and-a-half minute spacing that distance is approximately three nautical miles; for three minutes it is between seven and eight miles. The spacing to be applied between aircraft in sequence is decided by a Supervisor after close consideration of all the factors involved. The Approach Controller[s] process the traffic accordingly, varying spacing between individual pairs of aircraft as circumstances demand (excess departures etc).

It would be a very complex task to learn to achieve different spacing distances individually and by different methods, but it is not necessary. Once the sequencing process is learned the actual setting of final spacing does not change with different landing spacing, it is a comparatively simple matter of timing turns slightly differently to achieve the required result. VV Approach™ teaches the achievement of a five-mile sequence and in doing so also teaches the achievement of other landing spacings. As the number of landing aircraft in a sequence rises, so does the need for accuracy of final result if runway utilisation is to be maximised. So, the accuracy achieved is directly assessable from the number of aircraft processed in, say, one hour. The traffic numbers in the latter simulator exercises in VV Approach™ require the average final spacing over an hour of traffic to be no more than 5.4nm, a margin of 0.4nm, which equates to about 12 seconds in time. Excess spacing in any sequence is always cumulative, so if the average tolerance is exceeded an exercise becomes uncontrollable, giving a positive indication of student's lack of accuracy. Spacing below 5nm is not acceptable because aircraft require Wake Turbulence Separation and the reference distance for that in VV Approach™ is 5nm.

So, the Learning Outcome from VV Approach™ is the skill to process high-speed aircraft onto a runway of any alignment with a spacing of 5nm at landing, with a tolerance of - 0 and + 0.4nm for a period of one hour. The actual number of aircraft varies with the distance the first one is from touchdown at exercise start time, but is within the range 24 to 27. The aircraft are inbound from all directions, from the square downwind (right and left) to the straight-in (runway extended centreline) and in all conflict configurations.

The Learning Outcome is achieved from a starting point of zero previous knowledge or skills.