Equipment Exam Flashcards

Question

What happens when a wave is ducting?

Answer 1

It is bouncing off of a temperature inversion or under certain atmospheric conditions which may reflect VHF, UHF and SHF waves back to the ground and they will bounce around in this ‘duct’

Answer 2

Similar to ducting but with low frequencies bending around objects that would normally shadow the signal. Can be heard a great distance from the source as the low frequencies mean lower attentuation.

Answer 3

**Area Control** **Approach Control** **Aerodrome Control** - Air; traffic integration, approach monitoring - Ground; Runway protection, monitoring ground hazards

Answer 4

By calculating the time taken for a signal of a known speed to be recevied as an echo we can calculate the distance using the following equation. Distance= (speed x time)/2

Answer 5

Radio Detection And Ranging.

Answer 6

Primary (PSR) Secondary (SSR)

Answer 7

By sending out a pulse of electromagnetic energy and waiting for a reflection, as the speed of the wave is known (c) then the distance can be calculated easily. distance= (speed x time)/2 This tells us how far away the object is and by combining this with the information about which way the RADAR was facing when the signal was received we can determine the position of an aircraft as well.

Answer 8

1mm-100cm This is the same part of the electromagnetic spectrum as microwaves.

Answer 9

Permanent Echoes These are the position indications given by permanent objects in the area of operation of a RADAR, they can be used to check that the RADAR is still correctly aligned.

Answer 10

Unwanted returns on a RADAR screen, these can be caused by ground, buildings, or weather (the rain droplets in clouds is what causes clouds to reflect RADAR)

Answer 11

The visual indication, in non symbolic form, on a situation display of an aircraft obtained by PSR.

Answer 12

A generic term for the visual indication, in non symbolic and/or symbolic form, on a situation display of the position of an aircraft, aerodrome, vehicle or other object.

Answer 13

A visual indication in symbolic form, on a situation display, of the position of an aircraft, aerodrome vehicle or other object obtained **after automatic processing of positional data** derived from the source.

Answer 14

The situation which exists when the RADAR position of a particular aircraft is seen and identified on a situation display.

Answer 15

Term used to indicate that RADAR-derived information is employed directly in the provision of ATC service.

Answer 16

The screen. Displays the electronic information regarding position and movement of aircraft.

Answer 17

Transmission Reception Display

Answer 18

Is a transceiver that can transmit and receive, but only does one or the other at a time.

Answer 19

It is the device that creates the pulses which are modulated by the modulator into the pulses that the RADAR actually sends out.

Answer 20

This is the maximum technical range from which a target echo or transponder response can be received. This determines the PRI.

Answer 21

The Pulse Repetition Interval The interval between pulses necessary to receive a return from the unambigious range. ie how long would be needed between pulse replies to receive a signal from the RADARs maximum range. This determines the PRF

Answer 22

The pulse repetition frequency The number of pulses that can be trasmitted in a second. Higher PRF the greater the clarity of the position return displayed as you get more 'hits' on it.

Answer 23

Secondary Surveillance RADAR ## Footnote RADAR that works by the sending an interrogation signal to the aircraft transponder which sends a reply to the station. The distance is calculated by the time taken for the response to tbe received and the direction is taken from the direction the RADAR is facing. The response can also contain height and identity information as well.

Answer 24

The ground stations transmit the interrogation signal on 1030MHz Aircraft transponder sends the reply on 1090MHz

Answer 25

By sending a pair of pulses which are seperated by a certain time interval between each pulse. 8.5µs for Mode A 21µs for Mode C The aircraft will then recognise this and send back the appropriate information.

Answer 26

12 bits This limits the possible amount of codes to 4096 discrete codes

Answer 27

1. Discrete codes- Those assigned to individual aircraft 2. Non Discrete- Single codes issued to numerous aircraft ie conspicuity 3. Special codes- Applied to aircraft on certain occassions

Answer 28

Originating Region Code Assignment Method ## Footnote Codes are assigned depending on what participating area they come from. It is designed to reduce RTF and cockpit work-load by allocating an SSR code which can be retained from take-off to touchdown.

Answer 29

7500- Hijack/unlawful interference 7600- Radio Failure 7700- A/C emergency

Answer 30

Codes assigned to individual positions to identify aircraft being controlled by a particular unit to another unit. Helps in coordinating between units.

Answer 31

11 this is because the numbers 8 and 9 are now required.

Answer 32

Position indications and position symbols may overlap making them impossible to read or even causing the mode A codes to be incorrectly displayed. Is conteracted by a de-garbler

Answer 33

False Replies Unsynchronised in Time Falses responses being received. Removed by a de-fruiter.

Answer 34

For a given aerial height this will improve the low coverage but decrease the higher coverage

Answer 35

For a given aerial height it increases the higher coverage but decreases the lower coverage.

Answer 36

Cosecant Squared Because it saves power.

Answer 37

The diagram which shows the actual coverage of the RADAR system. Operational RADAR procedures are determined from this.

Answer 38

It will cause it to attentuate faster and increase the atmospheric effect on the coverage. Due to increased interaction with molecules in the air.

Answer 39

Enough, allowing for attentuation, so that the RADAR can detect an echo from an aircraft at maximum range.

Answer 40

The length of the pulse sent out by the RADAR This must be short enough to allow replies from previous pulses to be received and for the RADAR to enter receiving mode before transmitting again. This therefore determines the RADARs minimum range.

Answer 41

The thing that overcomes weather clutter.

Answer 42

Moving Target Indicator ## Footnote This makes the RADAR screen display only those targets which are moving as the rest are filtered out. This helps to reduce PE's and clutter. However this relies on radial movement of the aircraft between pulses otherwise it appear stationary.

Answer 43

If the aircraft is moving 90° to the RADAR beam tangentially the aircraft will not move radially and will therefore be filtered out by the MTI.

Answer 44

When the aircrafts radial distance changes by half a wavelength during one pulse occurence, can also happen when the distance is a multiple of half of the wavelength. It causes the blip to cancel itself. This normally happens when the aircraft is heading directly away or to the RADAR head.

Answer 45

* Coaxial cables (expensive and limited to short distances) * Radio link (operates in UHF to SHF frequencies, needs repeater stations if going a long distance) * Telephone link * Fibre optics

Answer 46

Processing of information by multiple RADAR heads. The airspace is divided into grids 16x16nm forming columns or air going upwards called RADAR sort boxes. This box will be covered by multiple RADAR's, the one offering the best signal will be the primary with others being the supplementary and the reserve meaning that even if one fails there are always back-ups. The pictures from these RADARs are pieced together like a mosiac.

Answer 47

Its a device that changes analogue signals from PSR and SSR into digital signals. Allowing further data processing such as Mode A squawks being replaced with the actual Callsign.

Answer 48

Once in a digital signal the RADAR can process the past movements of the indication and use these to calculate groundspeed.

Answer 49

Data from several RADARs combined in all parts of the screen, it determines an average position from all the sources to give a more accurate picture of aircraft positions.

Answer 50

* Significant points- nav aids, holding points etc * Final Approach Tracks * Airspace restrictions * Controlled Airspace Boundaries * Coastlines and rivers * FIR and national boundaries * Lat and Long

Answer 51

Selected ## Footnote It is a form of SSR that selectively interrogates aircraft instead of just generally interrogating them all. Individual interrogations reduces garbling and Fruiting. Allows each aircraft to have its own unique code.

Answer 52

1030-1090MHz same as all other SSR.

Answer 53

24 bits 16.75 million.

Answer 54

1. Operation Acquisition Phase- interrogator tracks conventional responders looking for new Mode S transponders and retains in its memory the individual addersses for the next phase. 2. Addressed survelliance phase- Mode S a/c individually interrogated for ATC identification, altitude, and other data.

Answer 55

The closest point of approach. The Mode S transponders TCAS procduces a CPA which includes a two level proximity warning, produced by talking directly with other aircrafts transponders.

Answer 56

It is uplinked from the ground Downlinked from the aircraft.

Answer 57

* Identification * Squawk * Level * Position

Answer 58

* Position * Identifiction * Flight level * Selected altitude * IAS * Ground speed * Mag heading * RoC RoD

Answer 59

Automatic Dependent Surveillance Broadcast ## Footnote Works like a passive radar receiving signals from onboard equipment from the a/c. A/C deduces its own position and passes down to the ground station. Can also be used as a downlink to send and receive messages from the a/c or ground, much like CPDLC except it has less pilot input. Can allow non-procedural approach procedures in area of little or no RADAR coverage. Can also be used to augument RADAR coverage in areas of RADAR shadowing, eg hills/ mountains near an airport. • ADS-B broadcasts; horizontal position, vertical position, and velocity; as well as other information. **• Can be used by aircraft or vehicles**. * Also can be received by ground facilities. * Enables a passive system to monitor, uniquely identify, and track all targets in range. * Suitable for ground, and airborne application. (For sole-source surveillance) * Is reliant on ALL users providing accurate information ALL of the time. Automatic- Always on-No operator intervention Dependent- The system relies upon very accurate GNSS navigation data. Surveillance- Provides aircraft position, heading, speed, altitude, identification, and other data. Broadcast- No interrogation required. Data is broadcast to any ADS-B station. - It uses a downlink and messages can also be sent from the antenna to the a/c * NATS are currently investigating the potential of using this for separation purposes.*

Answer 60

- Relatively inexpensive, 0.01% the cost of equivalent RADAR - Smaller Power requirements and footprint, allows installation in remote areas. - Comms links are satellite and Microwave

Answer 61

Multilateration ## Footnote Very similar to ADS-B. MLAT antennae on the ground receive position reports from a/c via Mode S or ADS-B broadcast, the exact position is then worked out using TDOA (time diffrence of arrival) which uses the difference in receipt times of the signal between different antennae to work out the position. Displays on the Situation display in the same way as ADS-B Short range ones can be used to augument SMR, much cheaper and easier to maintain than SMR also more accurate and faster. Need several antennae to achieve necessary coverage. Wide area MLAT can be used to cover larger volumes of airspace. In augmentation with RADAR (which is sometimes impractical).

Answer 62

Aircraft and vehicles, must be equipped with transponders to be visible though.

Answer 63

1090MHz same as SSR

Answer 64

1. Position 2. Airborne Velocity 3. Aircraft Identity

Answer 65

Automatic Dependent Survelliance Contract ## Footnote A 'contract' is established between the aircraft and the ground station. This contract establishes what reports the aircraft must make to the ground station and when they must be made. The ATSU will have to establish what type of contract is to be made before the ADS-C reports will be sent from the aircraft.

Answer 66

1. Periodic contract 2. Demand contract- ATC will demand a report from the a/c now, such as a level report. 3. Event contract- Aircraft is told to make a report when doing a certain thing eg vacating a certain flight level 4. Mayday contract- only the pilot can cancel this one.

Answer 67

**Advantages** - Less power for similar range - No ground or weather clutter - Display and identification of aircraft simplified - Level Info - Emergency Squawk Codes - Can be equipped with safety nets (STCA etc) **Disadvantages** - All a/c need a transponder - No weather returns - Fruit - Garbling of TDB's - Fading - No permanent echoes for calibration - Cant be used for controlling on its own (except during PSR failure) owing to needing a/c to squawk so needs PSR coverage too.

Answer 68

Short Term Conflict (STCA) – visual and (sometimes) aural warnings if potential aircraft conflicts detected. • (Medium Term Conflict detection (MTCD) gives much earlier notice of conflicts and is used in ACCs, but is considered a planning tool, not a safety net)

Answer 69

Minimum Safe Altitude Warning (MSAW) – visual and (sometimes) aural warning if radar system detects aircraft below minimum safe altitude, based on SSR transponder altitude readouts

Answer 70

Runway Incursion Monitor and Collision Avoidance System (RIMCAS) * Fitted to some surface movement surveillance systems * Provides Tower controllers with audio and visual warnings of potential conflictions on runways * (PSR and SSR returns can both trigger RIMCAS) )

Answer 71

Approach Monitoring Aid * Also known as Approach Funnel Deviation Alerting System (AFDAS) * Automatically monitors aircraft on final approach and provides visual and aural alert to Tower controller of any significant lateral or vertical deviation from final approach track or glide path

Answer 72

Controlled Airspace Infringement Tool (CAIT) * Radar system monitors squawks and mode C readouts to alert radar controller to any unauthorised entries into controlled airspace * A version of CAIT can also detect non squawking aircraft entering CAS which extends upwards from the surface with no upper limit e.g. the London CTR, above which lies the London TMA up to FL 195 and then class C airspace above that.

Answer 73

Aircraft and vehicles, must be equipped with transponders to be visible though.

Answer 74

Disadvantages - All a/c need a transponder - No weather returns - Fruit - Garbling of TDB's - Fading - No permanent echoes for calibration - Cant be used for controlling on its own (except during PSR failure) owing to needing a/c to squawk so needs PSR coverage too.

Answer 75

* Self contained * Independent operation-solely provides identification and fix of the aircraft * Non-reliant- A/C dont need a transponder * You get PE's, which can be used to calibrated * Weather Information

Answer 76

* No level info * Identification requires a much higher workload * Weather clutter * PE's can be obscuring * Range depends on transmitter power, target size and properties * No emergency indicator

Answer 77

Having both secondary and primary RADAR This is so you can over come the disadvantages of both.

Answer 78

No, it can only be used for the minimum time necessary to establish other forms of separation.

Answer 79

Flight Management System ## Footnote The overall computerised electronics system on the aircraft used to assist in nav, flight planning, and aircraft control.

Answer 80

1. FMC- Flight Management Computer 2. AFS- Auto Flight System 3. Navigation.

Answer 81

To compute real time nav data, and show it as a moving map for the pilots, this map will contain SIDs/STARS etc. It can also calculate the performance data based on weight, altitude etc.

Answer 82

Controller Pilot Datalink Communications ## Footnote A data link that allows for the transfer of text messages between ATC and the pilot, these messages can be uplinked straight to the FMS making them automatic. Improves communication capabilities in oceanic areas.

Answer 83

* Allows flight crew to print messages, less ambiguity especially for foreign pilots * Allows auto uplink of messages straight into the FMS * Allows crews to downlink complex route clearances and requests.

Answer 84

A mode selected by the pilot that informs ATC that the aircraft is experiencing an emergency, including changing the squawk automatically. Only the crew can initiate and turn this off.

Answer 85

No, the only 'readback' is a wilco message sent by CPDLC.

Answer 86

1. The sending of a CPDLC MAYDAY message automatically places the CPDLC and ADS into emergency mode. 2. The crew can also manually select ADS emergency mode, independent of the CPDLC.

Answer 87

The flight crew only.

Answer 88

Air Traffic Operational Telephone network

Answer 89

Selective calling Basically a way of reducing pilot fatigue by no longer requiring them to maintain a constant listening watch. A selective call will be sent to the aircraft which will create a visual and aural alarm in the cockpit letting them know that ATC wishes to talk to them.

Answer 90

Aircraft Communications Addressing and Reporting System ## Footnote A system similar to CPDLC which is used by the airline/operater to speak or download parameters from the aircraft.

Answer 91

1. Air Traffic Control ATC 2. Aeronautical Operational Control AOC 3. Airline Adminstrative Control AAC

Answer 92

Aeronautical Fixed Telecommunications Network

Answer 93

Meteorological Operation Telecommunication Network Europe.

Answer 94

D=_C (speed of light) x Time_ 2 Plugging the speed of light into a simple speed, distance, time equation but by dividing by two as you only want to know the distance to not to and from.

Answer 95

3x10⁸m/sec 300,000,000m/sec

Answer 96

Authorised Authority.

Answer 97

1. Horizontal 2. Vertical 3. Velocity

Answer 98

1. SS 2. DD & FF 3. GG & KK

Answer 99

Distress messages and traffic

Answer 100

Urgency messages and traffic

Answer 101

Met Messages Flight regularity messages Aeronautical Adminstrative messages NOTAMS

Answer 102

* FPL- incl FPL messages such as DLA, CHG, CNL, ARR, DEP * Co-ordination messages- CPL (current FPL), EST (estimate), CDN (coordination), ACP (acceptance), ACK (acknowledgement) * Supp messages- RQP (request FPL), RQS (request supp FPL info), SPL (supplementary FPL) * Control messages * Traffic information * Met info * Air traffic

Answer 103

Reservation messages General a/c operating agency messages

Answer 104

Overseas Fixed telecommunications Service

Answer 105

* Aerial size, shape and height * Size of the target * Atmospheric conditions * Transmitter power * Receiver Efficiency * PRF * Pulse length

Answer 106

Narrow Beam in azimuth Wide beam in elevation

Answer 107

The line of sight distance along a slant direction between two points which are not at the same level relative to a specific datum.

Answer 108

This is because the sounds do not require excellent audio clarity of tone unlike radio broadcasts of music.

Answer 109

ADS B extended Squitter which transmits the aircraft information on 1090MHz