Aircraft Wake Avoidance
Aircraft Wake Avoidance Solution
Wake Watch’s real-time systems enable airport capacity growth with existing infrastructure.
Wake Watch’s Dynamic Wake Avoidance Solution measures and analyzes wake, wind and atmospheric conditions present at an airport to safely optimize runway capacity in real time. Safe optimization of capacity is attained by using real-time measurements to show when the optimum atmospheric conditions can be used to safely maximize capacity such as when no temperature inversion layers are present in higher wind in unstable atmospheres, conditions which minimize the wake vortex lifetime. Current wake separations assume the a wake turbulence encounter is possible at any time of the day. By measuring the critical parameters of the atmosphere in real time such as the head wind, cross wind, turbulence, stability and inversion layer gradients, as assessment of the likely occurrence of short or long lived wake vortices can also be made in real time. When the vortices are short lived such as in higher speed winds and unstable atmospheres when no inversion layers are present, separation can be safely minimized. Longer lived wake vortices are present in lower speed winds and stable atmospheres at. Wake vortices become especially long lived and can be present in the flight path when inversion layers are present. This Solution gives airports more information to make more informed decisions to be able to increase runway capacity when it is safe to do so. How it works-
- Wake Watch’s systems measure the structure of the atmosphere and the wake lifetimes in real time to determine what the current spacing should be.
- The real time data from the wind profiler is used to assess the current state of the atmosphere and to then make an assessment of the most likely wake lifetime. The graphic below shows such a wake lifetime assessment. If there is an inversion layer present, which increases wake lifetime, then the likely location for a wake encounter is also shown on the 3 degree glide slope.
- This wake estimate graphic trigger points will be optimized further using the data from our wake array. The wake lifetime estimates can be checked against the current actual wake lifetimes below.
- The wake lifetime estimates are constantly being updated using the measurements from the wake array ( wake lifetime) and the wind profiler ( wind data and temperature estimates that show the inversion layer heights). When the atmosphere is changeable then the wake lifetime estimates tend to also be variable.
Click on the image below then, Refresh/Ctrl F5 to see the latest wake lifetime and position estimate. When there is no inversion layer then the wakes fall at around 1.6m/s and have short lifetimes so an estimate of the wake position is not relevant. NOT approved for operational use.
The Current warning level is in 5 increments. Level 1 for wake lifetimes < 0.5 minutes. Level 2 for wake lifetimes < 1 minute. Level 3 is for wake lifetimes < 2 minutes. level 4 is for wake lifetimes < 3 minutes and shows the possible wake encounter location on the glide slope. level 5 is for wake lifetimes > 3 minutes and shows the possible wake encounter location on the glide slope. The small box graphic shows the warning levels for the last 40 minutes.
In normal atmospheres when even a moderate amount of turbulence is present aircraft wake vortices fall below the flight path at around 1.5m/s and typically last less than 30 seconds. Sometimes, mostly at night, temperature inversion layers can be present which can cause the wake vortices to rebound ( rather than falling ) and last for many minutes, posing a severe hazard to any aircraft following too closely behind. The temperature inversion layers are the only atmospheric phenomena that cause the aircraft wake vortices to rebound or last longer. A real time wake measurement data graphic of wake vortex measurements is shown below. The ICAO 24 bit aircraft identification number is shown in the bottom annotation together with the aircraft flight number. The wind parameters are also shown there. The graphic below updates every minute, provided that aircraft have recently passed over the wake array. The vertical red line is present when the aircraft passes over the wake array and is caused by the aircraft noise. The recording then runs for 5 minutes before stopping and waiting for the next aircraft. The wind speed is shown for runway 34 departures( Northerly wind) and 16 arrivals (Southerly wind). The 16 arrivals are at a height of 60m above the wake array. Often the vortices are not evident at all such as when the convective activity of the atmosphere or high winds result in the vortices demising rapidly. The dynamic range of the image below is from 1 volts (black) to 200 volts (red) so the image is linear, a range of 46dB. This allows the atmospheric structure and the wake vortices to be easily seen. The current data from the outputs of the 5 wake array sensors located closest to the center line are shown below. This data is updated mostly in close to real time, but at times it also shows historical data when the graphics display is catching up. The graphic of wakes below indicates the direction of the aircraft (arrival, departure) and the ground wind speed at the time. The measurement is triggered if the aircraft is below 430m when it is over the wake array.