post from a pilot

This is copied from Ozestock posted by Charliemoso:


Gday all,

I finally have the chance to repay many many debts with this post. firstly thank you to all posters on OXR and AVL that have provided me with a wealth of knowledge and led me to be a long term holder in both. Now I would like to help return the favour.

I am an Air Traffic Controller and a qualified pilot and I would like to give you just one example of how this profiler could work.

Aircraft produce wake turbulence (wake vortex, same thing) as a by-product of the lift that the wings make which lifts the aircraft in the air. these vortexs can be very vicious and I personally have felt the full brunt of them when i flew my aircraft too close behind another and was flipped sideways. The violence of the wake vortex is directly proportional to the weight of the plane. This is because the heavier the plane, the more Mr Newtons theories come into play and the more lift is needed to get the plane in the air - more lift = more vortex.

As air traffic controllers we are required to keep planes a certain distance appart because many accidents have occured when planes encounter these vorticies. I will use some examples.

1. A small aircraft must wait 2-3 minutes to take off after a jet like Qantas/Virgin Boeing 737 has taken off in front of it.
2. A jet like a Boeing 737 must fly something like 4-5 miles behind a jumbo jet when approaching the runway to land.
3. A small aircraft must not land anywhere within 2.5 minutes of a Qantas/Virgin type jet and even longer behind a jumbo jet.

These rules are NON NEGOTIABLE...we cannot fudge these rules because it can be dangerous.

Now imagine the possible use of the profiler if in my Air Traffic Control tower I have a small computer screen that shows me a graph as the vortex disipates. As soon as it has disapated I may then clear the next aircraft to take off. Now look at the timings - t+42 seconds was quoted in the report (but they dont specify the type of aircraft that made it which is difficult. remember bigger = heavier = more vortex). But lets add a safety margin and even then it would be about 1 minute. So in my tower I see the vortex is gone within a minute and the next aircraft can go. Instantally I have reduced the wait of the small aircraft departing behind a Qantas/Virgin jet from 2-3 minutes to 1 minute. Right there you have just doubled the capacity of the runway used for take off. A similar system could be used for the landing runway. Now think of that on our poofy small Aussie airports. Now imagine the application for an airport like London Heathrown, chigago O'Hare and things start to get mind boggling.

Please feel free to draw on my knowledge in this area...ask questions as you please. I have been a silent reading of the goldie boards for a long time....hopefully i can give some knowledge back.