Air Traffic Control and Airspace At Farnborough  The following information is of a very general nature, as there are many different variables, caveats and exceptions which apply, and is meant merely as an introduction to the complex world of air traffic control. The ATCO (Air Traffic Controller) roles at Farnborough There are different types of controller skills and air traffic units, providing different types of services. Farnborough is an approach control unit and comprises three main roles, as follows:     * Tower controller at the top of  the control tower or VCR (Visual Control Room)     * Radar approach controller working in the radar operations room, at the foot of the tower     * LARS (Lower airspace radar service) again working downstairs in the radar room Other than at airports, the other main Air Traffic Service providers are Area control units, who deal with higher level en-route traffic and more congested areas such as around the London airports.  There are three Area centres in the UK, located at Swanwick (near Southampton), Manchester and Prestwick (Scotland).  In 2009 these will be amalgamated into two, at Swanwick and Prestwick. What are the tools of the trade?  RTF (radio telephone) VHF (very high frequency) radio.  Being able to communicate with aircraft and vehicles is obviously the primary tool for the ATCO.  The ATCO wears headphones with a microphone attached. When operating in the VCR, the controller will visually monitor arriving, departing and taxing aircraft except in poor visibility where the movement of traffic is deliberately slowed and simplified to allow the controller to work in a more procedural manner. Radar, of which there are two types:     * Primary radar which works simply like a bat, sending out a radio wave, which if there is something out there will bounce back. Other than aircraft other objects may create a “radar return” such as a pylon, heavy rain or a flock of birds.     * Secondary radar, where a coded beam is sent out.  An aircraft fitted with some equipment called a transponder will reply with a 4 digit number selected by the pilot and may also tell height, speed and other information such as whether the aircraft is climbing or descending. Paper strips and holders.  Details of all airfield aircraft are provided on paper strips which the ATCO will annotate to indicate what instructions/information has been passed.  The strips are a key element in maintaining a mental picture of the traffic situation and can act as a back up in low visibility. A “history” of the aircraft movement will also be maintained on the radar to give the controller an idea of the velocity of the aircraft.  Called trail dots, there are usually about 5 of these displayed behind the aircraft as diamonds. ILS (Instrument Landing system) comprising two beams radiating out from the runway. One will give the glide slope, the other the runway centreline and onboard aircraft equipment will enable the pilot to follow these beams down to facilitate a safe accurate approach and landing. At Farnborough the Glide Slope is set out 3.5°, slightly steeper than at other airports, to ensure that arriving aircraft are as high as possible over residential areas. What does the Farnborough ATCO do? The tower controller’s main priority is to protect the runway, ensuring that all landing and departing traffic always have a clear runway ahead. They also control all taxiing aircraft and vehicle movements by looking out of the window and by issuing instructions to aircraft and vehicles using the RTF. The radar approach controller will look after arriving and departing traffic.  Generally speaking, the controller will instruct the aircraft to climb and descend to safe levels, which will separate against other Farnborough traffic by either 3miles horizontally or 1000ft vertically, or provide traffic information and if required, advice for avoiding action against other transiting aircraft operating in the vicinity.  For departing aircraft this may result in the aircraft being given different instructions than would normally be expected. They will also provide headings for inbound aircraft to steer them to the ILS which will then guide their approach into the airfield. The other key service provided at Farnborough is the Lower Airspace Radar Service or LARS to transiting traffic. Aircraft in the vicinity can call on an ad hoc basis and receive helpful information about weather, altimeter setting pressures, assistance in the case of an emergency, warning of other conflicting traffic and other such useful information. This service helps to create an increased known traffic environment which allows ATC to function more effectively but is an advisory service only and therefore may not be obeyed by all pilots. An increasingly large area of the SE of England is now catered for in this respect by Farnborough. The ATCO is helped in all of these scenarios by ATSAs (Air Traffic Service Assistant) who amongst other things will amend flight plans, take phone calls, record statistics and if you’re very lucky make the odd cup of tea. The Airspace Environment The UK operates a classification system to define the various different types of airspace. These range from Class A to G where Class A is the highest level of controlled airspace and Class G is uncontrolled airspace. Class A airspace is located around the major airports in the UK where entry is only permitted under the control of ATC. Class G is essentially all the remaining airspace outside of areas A to F where any aircraft (including gliders, microlights etc) can fly without contacting  ATC and are therefore free to make their own decisions subject to the Rules of the Air. Aerodrome Traffic Zones (ATZ) are areas set up around airports which in Farnborough’s case is a 2.5mile circle centred on the airport which extends to a height of 2000ft. Aircraft wishing to enter the ATZ must contact ATC and obey any instructions given. Farnborough airport is situated in an area of open or uncontrolled airspace, where pilots are free to operate without air traffic control.  This can make controlling traffic at Farnborough a challenge at times as there may be aircraft operating in the vicinity of the airfield whose intentions and altitude are unknown while ATC have to maintain separation with traffic under their control. This is especially the case over the summer period where there is a lot of light aircraft activity, particularly from local airfields such as Blackbushe and Fairoaks and at weekends when uncontrolled gliders operate at Odiham. Above 3,500ft (amsl) becomes controlled airspace, which is currently operated by the Area centre at Swanick. Most of the traffic arriving and departing Farnborough will have either left or being joining controlled airspace, and Farnborough has various agreements about how this is achieved with the area centre. The diagram shows a cross section of the surrounding area along the length of the runway at Farnborough (060° to 240°) with distances in miles from the airport. Noise Abatement Procedures Airports that operate in Controlled Airspace are permitted to have Standard Instrument Departures (SIDs) and Standard Terminal Approach Routes (STARs) which are procedures and checkpoints used to enter and leave the airway system from or to an airport. The SIDs and STARs define pathways that aircraft must follow. As Farnborough is outside Controlled Airspace it is not possible to have SIDs and STARs, however a procedure known as Noise Abatement is adopted in order to minimise the impact of the aircraft to the surrounding community by giving pilots a preferential route to and from the airport subject to other aircraft operating in the surrounding area. On departure ATC will give aircraft their departure instructions which will include the instruction to follow Noise Abatement. There will be times when Noise Abatement has to be cancelled due to unknown or conflicting traffic, operating in Uncontrolled Airspace that is not in contact with Farnborough ATC, which will result in the aircraft following a non-standard route. Noise abatement procedures that were used in the 1980’s and 90’s when the airport was still under military control cannot now be used due to the different regulations applied to civil airports and the surrounding airspace.1992. AERODROME FACILITIES FARNBOROUGH AERODROME CONSULTATIVE COMMITTEE An independent Consultative Committee established by TAG Farnborough in accordance with a Section 106 agreement of the Town and Country Planning Act