Airmanship Knowledge Learning Outcome 1 Air Traffic Control Uncontrolled copy not subject to amendment Airmanship Knowledge Learning Outcome 1 Air Traffic Control Revision 1.00

Airmanship Knowledge Learning Outcome 1 Understand the types of airfield operations used for the control of aircraft

Contents Control Towers Controllers Communication Systems Visual Communications RADAR Approach Aids

Air Traffic Control

Introduction On RAF Airfields all movements of aircraft, both on the ground and in the air are monitored by Air Traffic Control (ATC)

The Control Tower Is always in a prominent position in the aircraft manoeuvring area Houses electronic & radio equipment and may also have a Bird Control Unit

The size & design of ATC Towers varies considerably. The Control Tower The size & design of ATC Towers varies considerably.

Aerodrome Controller Is in charge of movements: On the Ground In the Air Sometimes Called: Airfield Controller Local Controller Movements include: Aircraft Vehicles Pedestrians Is also in charge of aircraft in the circuit, They always work in the control room, with their big glass windows, so they have uninterrupted views of the airfield. On large airfields this is split in two as there is too much work for one person. Aircraft movements on the ground up to the runway are controlled by a controller called Ground. Aircraft movements on the runway and in the local area are controlled by a controller called Tower.

Approach Controller On light usage airfields On heavy usage airfields The departures are separated out under the Departures Controller They control aircraft: departing the airfield making instrument approaches Both use RADAR displays, RT and landline communications 1. Controls aircraft departing the airfield circuit and those making instrument approaches. 2. May sometimes provide radar service to aircraft in transit through the area of responsibility of the airfield. 3. As most of the aircraft are out of sight of the field the approach controller does not need a window. 4. Instead he obtains information from RT , landline communications, and Radar displays

Runway Controller For more effective control a Runway Controller may be used: At small airfields with lots of take-offs and landings They are in direct contact with Aerodrome/Local Controller Caravan is painted in red and white squares, positioned to the left of the touch-down end of the runway in use.

Runway Controller The Runway controller can refuse aircraft permission to move onto the runway, land or take-off in some circumstances

Runway Controller For example they might: Prevent an aircraft from landing with its undercarriage retracted by firing a RED flare. Stop an aircraft from taking-off which had for example a panel unlocked or a fuel leak, by showing a steady RED on the signalling lamp.

Runway Controller Warn vehicles or aircraft on the ground to move clear of the landing area, by showing RED flashes on the signalling lamp. Give permission to take-off, with a steady GREEN on the signalling lamp.

Communication Systems Good Communications are essential to Air Traffic Control

Communication Systems Swift and accurate contact is achieved through the use of: Special Telephones Tele-Talk Systems Radio Telephony (RT) (Ground To Air) Uses VHF and UHF to talk to aircraft and vehicles. These frequencies provide clear lines of communications. Each airfield and its section have their own frequencies.

Visual Communications Stationary Object Hazard Bad Ground Markers 0.61 metres square

Visual Communications Helicopter Operating Areas: The ‘H’ is 4 metres high by 2 metres across It may also have a box around the ‘H’. Well clear of fixed wing aircraft OR

Radar Stands For: RAdio Detection And Ranging

Radar Consists of a Transmitter and a Receiver A short pulse energy is transmitted from an aerial and the receiver “listens” for an echo.

Radar The receiver detects which reflections are from aircraft, and it can determine their position, direction of travel and speed. This information is then displayed through a cathode ray tube onto a screen. In this way radar has become the “eyes” of air traffic control

Radar Aids The two main radar aids likely to be seen at Royal Air Force airfields are: Surveillance Radar Precision Approach Radar (PAR)

Surveillance Radar Is used both to monitor air traffic passing through an area and as an airfield approach aid.

Surveillance Radar Enables the controller to locate the aircraft and direct it to a position and height near the airfield

Surveillance Radar Can be used for an airfield approach: Surveillance Radar Approach (SRA) The pilot hears directions to put him on the runway centre line and also heights that he should be passing every mile i.e. “On runway centre line at 5 miles, should be passing 1850Ft”

Precision Approach Radar The controller has two screens, one for the aircraft’s elevation (height) and one for azimuth (left and right), relating to the approach path

Precision Approach Radar The controller passes instructions by RT to the pilot to guide the aircraft down the correct glideslope and centreline towards the touch-down point The procedure is called a Ground Controlled Approach (GCA) or PAR Approach. The pilot hears directions to put him on the runway centre line and the ideal glidepath i.e. “Left of centre line, come right 2 degrees, slightly low on glidepath, not correcting”

Precision Approach Radar

Precision Approach Radar PAR 2000 Radar

Radio Aids The two main Radio Aids likely to be seen at Royal Air Force airfields are: Digital Resolution Direction Finding (DRDF) Instrument Landing System (ILS)

DRDF It is a common airfield approach aid at small airfields but is seldom used at large busy airfields It receives a carrier wave only transmission (no speech) from an aircraft and displays it on a CRT as a green line called a “trace”. Enables the approach controller to tell the pilot what course to fly to the vicinity of the airfield for a visual approach Controllers can direct the aircraft to a point above the airfield and from there control its descent through cloud (CDTC) to a height and position on the approach from which the pilot can either land visually or employ a runway approach aid.

Instrument Landing System ILS is a runway approach aid: Fixed transmitters on the ground send out a special pattern of radio signals These define a radio beam that is like a pathway in the sky The pathway then leads to the touch-down point on the runway

Instrument Landing System Glidepath ILS transmits 2 frequencies 90Hz signal is strongest, so aircraft is above the Glidepath Localizer Transmitter Glidepath Runway 90Hz 150Hz

Instrument Landing System Glidepath ILS transmits 2 frequencies 150Hz signal is strongest, so aircraft is below the Glidepath Localizer Transmitter Glidepath Runway 90Hz 150Hz

Instrument Landing System Glidepath ILS transmits 2 frequencies Both signals are equal, so aircraft is on the Glidepath Localizer Transmitter Glidepath Runway 90Hz 150Hz

Instrument Landing System Localizer ILS transmits 2 frequencies 90Hz signal is strongest, so aircraft is right of the Localizer Localizer Transmitter Glideslope Runway Runway Centre Line 90Hz 150Hz

Instrument Landing System Localizer ILS transmits 2 frequencies 150Hz signal is strongest, so aircraft is left of the Localizer Localizer Transmitter Glideslope Runway Runway Centre Line 90Hz 150Hz

Instrument Landing System Localizer ILS transmits 2 frequencies Both signals are equal, so aircraft is on the Localizer Localizer Transmitter Glideslope Runway Runway Centre Line 90Hz 150Hz

90Hz 150Hz 90Hz 150Hz Localizer Transmitter Glidepath Runway Localizer Glideslope Runway Runway Centre Line 90Hz 150Hz

GPS Approach Some airfields have been approved for GPS Approaches as long as the aircraft equipment has been approved. The GPS Approach is flown on the same instruments as an ILS Approach and gives the same indications.

Questions?

QUESTION WHICH BUILDING ON AN AIRFIELD HOUSES THE PEOPLE THAT MONITOR AIRCRAFT ON THE GROUND AND IN THE AIR? A. AIR TRAFFIC CO-ORDINATION ROOM B. AIRBORNE TRAFFIC CONTROL ROOM C. AIR TRAFFIC CONTROL TOWER C. AIR TRAFFIC CONTROL TOWER D. AIR TRAFFIC CO-ORDINATION TOWER

QUESTION WHICH OF THE FOLLOWING WOULD NORMALLY WORK IN A GLASS WALLED ROOM IN A CONTROL TOWER A. PAR CONTROLLER B. AIR CONTROLLER C. APPROACH CONTROLLER D. AIRFIELD CONTROLLER D. AIRFIELD CONTROLLER

QUESTION HOW DOES AN APPROACH CONTROLLER RECEIVE INFORMATION ABOUT AN AIRCRAFT A. RT, LANDLINE COMMUNICATIONS AND RADAR A. RT, LANDLINE COMMUNICATIONS AND RADAR B. RADAR ONLY C. RT ONLY D. RT AND LANDLINE COMMUNICATIONS

QUESTION WHAT COLOURED SIGNAL WOULD BE USED BY A RUNWAY CONTROLLER TO CLEAR AN AIRCRAFT FOR TAKE-OFF ? A. A STEADY RED B. A FLASHING GREEN C. A FLASHING RED D. A STEADY GREEN D. A STEADY GREEN

QUESTION HOW DOES THE CONTROLLER PASS PAR INSTRUCTIONS TO THE PILOT ? A. RT A. RT B. RADAR C. MORSE CODE D. RF BEAM

QUESTION WHERE DOES THE PAR ALLOW THE PILOT TO GUIDE THE AIRCRAFT TO ? A. TO THE DESIGNATED DISPERSAL AREA B. TO THE CORRECT GLIDESLOPE AND CENTRELINE B. TO THE CORRECT GLIDESLOPE AND CENTRELINE C. TO AN AIRWAY IN CONTROLLED AIRSPACE D. TO THE TAKE-OFF POINT

QUESTION DRDF IS USED TO ? A. DIRECT AN AIRCRAFT WHILE TAXYING B. DIRECT AN AIRCRAFT AFTER TAKE-OFF C. DIRECT AN AIRCRAFT TO THE VICINITY OF THE AIRFIELD FOR A VISUAL APPROACH C. DIRECT AN AIRCRAFT TO THE VICINITY OF THE AIRFIELD FOR A VISUAL APPROACH D. DIRECT AN AIRCRAFT TO THE RUNWAY TOUCHDOWN POINT

QUESTION AN ILS APPROACH IS USED TO ? A. TALK AN AIRCRAFT ONTO THE CORRECT GLIDEPATH AND CENTRELINE B. FOLLOW ELECTRONIC SIGNALS ONTO THE CORRECT GLIDEPATH AND CENTRELINE B. FOLLOW ELECTRONIC SIGNALS ONTO THE CORRECT GLIDEPATH AND CENTRELINE C. APPROACH THE AIRFIELD FOR A VISUAL APPROACH D. DEPART THE AIRFIELD

QUESTION A GPS APPROACH IS DISPLAYED ON THE SAME INSTRUMENTS AS ? A. A PAR B. A DRDF C. AN ILS C. AN ILS D. AN SAR