(Image courtesy Steve Parker)
As part of the Visit ATC month (which I have blogged about before) I was invited to go and spend some time with the good folks down at ATC in Farnborough.We happened to go on a really good day as the weather was fine and - as an added bonus - the Farnborough Air Show press day coincided with our visit. There were several unusual planes there and a fly past of Extra's had been arranged.
The Tower
We were met at the gate by Lyn who would be our guide for the day and - once all our party had arrived - we headed up the control tower (Two 'stops' in the elevator, but in actual fact over 100ft in the air)
The control tower was an oasis of calm considering the number of movements it deals with. Local planning caps the limit at 25000 per year, but one controller and an assistant manage all this themselves (However, during the air show there is another controller as well).
The view from the tower was fabulous. As you would expect the whole of the airfield was visible as well as the overhead for nearby Blackbushe, and the Bagshot mast that delineates the southwest corner of the Heathrow TMA. Curiously, though, RAF Odiham (whose MATZ is controlled by Farnborough and is about 8 miles away) is not visible due to rising land on the western approaches to the airport.
Looking out over the airfield we could see a couple of special planes in for the press launch. I saw what I think was a DC3 Dakota as well as a glider and a Dove. They were all parked over to the right of runway 06.
Lyn explained the workings of the tower. All flights are controlled by paper strips. These are mounted on colour coded bars to help indicate movements. Blue bars indicate take-off's, buff/brown bars indicate landings and a third colour is used for overflights. When a flight plan is filed a strip is printed from the computer showing all the details and the assistant mounts it in it's correct coloured bar. As the plane calls in the controller can then match it with its strip and know where it should be and when. It is usually handed over to the tower about 6 miles from touchdown (and vice-versa for take-off's)
Shortly after we arrived the flight of Extra's turned up. We could see them approaching from the east and they flew to the north of the airfield and circled for a while awaiting clearance. After an incoming plane had landed they were given clearance and approached from the east. The did a flyby along the runway in perfect formation, sweeping in a lazy horizontal circle at the western end to approach back from the west. On their westerly approach they were given looping permission and, just short of the threshold they all pulled back and did a perfect loop-the-loop at fairly low level before tracking back down the runway and performing an un-and-break to prepare for landing. Each plane broke high and right, in sequence, to give separation from it's neighbour, prior to turning back downwind and doing an abbreviated base/final turn. All four plans landed within 90 seconds. Most impressive.
We moved downstairs to the part which I, personally, was the most interested to see :
Farnborough LARS.
Farborough LARS is now the radar installation that monitors all non-controlled airspace in the South West of England. Their coverage stretches from the South coast as far North as Cambridge & the Fens and from the East coast as far West as Southampton. All this is managed through 3 controllers sitting in a room at the foot of the tower at Farnborough!
The radar screens are brand new and state of the art, able to identify both primary and secondary signals, but with the ability to process secondary signals prior to displaying them. So, for example, a controller can say 'I only want to see things that are moving at a speed greater than 60 knots'. This will effectively remove anything that is slower than
that from the screens (gliders and the like). Transponder codes can be identified quickly as well and preprocessed prior to display. This means that anyone squawking '7000' will appear with a 'W' next to their blip. Anyone higher than a predefined altitude (say 25000 ft) will appear as a 'U' and anyone showing a known airliner transponder code will have their flight call sign displayed ('BAW297', for example). Geographical features can be added (or removed) as needed and the whole scale can be changed if required. This makes the screen a lot easier to read.
Flight Strips
I sat with Emily (who was controlling the LARS East sector out in Kent) and we chatted about how things work when a GA pilot contacts them. Back in the days when you did your RT exam you were taught the sequence of information to pass when asked to 'pass your message'. This sequence is:
- Call-sign
- Aircraft type,
- Point of departure and destination,
- Altitude with altimeter setting,
- Intentions
- Request.
Transponder codes
The allocation of transponder codes has always seemed to be a bit random to me. But it appears that there is a method to the madness. Code are allocate depending on your controller unit and your departure airport. For example a plane being controlled by Farnborough LARS west departing from Blackbushe will usually be given a 403x code. The numbers are allocated sequentially and reused as the planes transfer to other controllers.
Each strip is given a transponder code and dropped into the stack sequentially. That way the controller can identify a plane on the screen through it's transponder code then get the call sign for that plane on the strip.
TIP: If you want a Radar Information Service, it's best not to ask for this during busy periods, or in an area where there are lots of aircraft. RIS's increase the controller workload to the detriment of other aircraft. Try flying out over the Kent area if you want a quiet patch - an RIS at that point will usually be accepted
Controllers usually work a maximum 2 hour stretch (Which, if you're controlling Farnborough LARS West, is a LOT of work) and then take a break.
Despite the fact that they were short of folks (the recent expansion of the LARS service to include LARS North and LARS East had stretched them to the limit) everyone was more than happy to talk (usually while controlling planes and answering phones at the same time) and overall the group spent a little over three hours in their company.
I would like to thank Lyn Combe and everyone at Farnborough ATC for their time and hospitality. It made the day really interesting.
