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32 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What does VOR stand for? |
Very high frequency Omnidirectional Range |
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What frequency band do VOR’s work off? Where does this lie relative to the VHF comm? |
112.00-118.00 Mhz Just below the VHF comm |
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How does the VOR work? |
The transmitter send out 2 signals, one is a reference signal and the other is a variable phase signal. The receiver compares the phase of the 2 signals and works out which radial you’re on. It then compares this to what’s selected in the OBS and deflects the CDI to show the difference between what you have and what you want |
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What are the VOR errors? |
Airborne equipment error (error within the receiver itself) Vertical polarisation error (when plane is in bank so antenna not level) Ground station error (from the equipment) Aggregate error (the total of all errors combined usually +/- 5 degrees) Site/terrain error (bending/scalloping of signals due to obstacles close to the site) |
AVGAS |
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Does a VOR station allow for magnetic variation? What about an NDB? |
A VOR yes, so tracks are magnetic, if an aircraft is in a different variation area to the VOR then they just track ignoring the difference, a track of 270 degrees would remain constant regardless of where they were.
If tracking to an NDB then you’d need to alter your track allowing for the variation difference between you and the station. Eg. Station is 10 degrees variation and you’re at a spot with 12 degrees then you’d head 268 for a track of 270 |
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What does using a Doppler VOR achieve? Do you need anything special in the plane to receive Doppler VOR? |
A Doppler VOR will eliminate any site effect error by using FM instead of AM Nothing special required in the plane to receive it. |
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What are the errors of the NDB? |
Mountain effect (reflected from mountains/hills) Interference (from other NDB’s particularly at night) Night effect (skywave interference) Terrain effect (attenuation over sandy/icy country) Coastal refraction (signal best towards land if receiving over coast) Height effect (reduced range at low altitude due to attenuating surface) Aircraft error (error in aircraft equipment- rare with new equipment) Thunderstorms |
MINTCHAT |
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The radio waves from an NDB consist of two electromagnetic fields, what are they? Which direction do their waves run? What are the names for the two antennas required? What do they do? And what do they look like? |
Electric field (E Field) vertical waves Magnetic field (H Field) horizontal waves Loop antenna determines the direction of the beacon down to two locations, 180 degrees apart. It is the flat antenna usually on the bottom of the belly. The sense antenna is the wire from cabin to tail and it determines which of the two positions worked out by the loop antenna is the correct one. *new systems have these two combined and are usually mounted on the bottom |
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What are the modes on an ADF for? |
ANT - antenna - best audio, good for identifying station BFO - used more overseas, stands for Beat Frequency Oscillator it sends a signal to the NDB that will only identify itself after BFO-ing it TEST - used to test it, needle should swing around to 90 degree position while button is pushed and held ADF - normal mode for navigating |
There’s 4 of them |
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What radio band does DME run on? |
UHF |
3 letters |
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What distance does a DME show you? When will the GS information be incorrect? |
DME shows slant distance, in a direct line from you to transmitter. It will only read correct GS if going to or from station, and even then if you are high due to slant error there will be errors on GS, when overflying and you’re directly over the station gs will read 0. It will appear that you’re slowing down the closer you get to station. |
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DME is a form of what? How is it tuned? How does it work? |
Secondary radar Tuned automatically when associated VOR is tuned Uniquely coded interrogator signals are sent from a/c to station then if coded correctly station responds, the time taken for the transfer of signals determines distance. |
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If flying at 9000ft, at what DME distance does slant range error begin to come into effect? What may happen if there’s lots of traffic tuned into one DME? To what distance does DME work? |
Only about 2nm from station If too many aircraft locked into DME then the ground station will automatically desensitise so it can only hear and reply to the strongest interrogations, this can result in shorter DME range DME will work similar distances to VHF |
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What are the two kinds of radar? How do they work? |
PSR primary surveillance radar (old) works when radar on ground sends up a signal and that signal bounces off stuff, the signals that bounce back off the hard stuff create a picture. Very limited ability lots of clutter small planes may not create a paint
SSR secondary surveillance radar (new) a ground based interrogator sends up a signal, the aircraft transponder reads it and sends back a uniquely coded signal to identify itself. Much less clutter |
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Most atc facilities have which kind of radar? What do the primary and secondary radar dishes look like? |
Both The primary is a curved dish, spins 10 times per minute for approach and 6 for longer distance Secondary radar is a straight bar looking a bit like a radiator sitting on top of primary radar and spins with it |
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What is average effective distance if secondary radar? The spinning radar can only ‘hear’ interrogations from aircraft it is facing at the time it receives the radio signal. How do we get around that? What are the limitations to the design? |
110nm but can vary depending on the site. Get around it with ‘side lobes’ on the back of the dish. Works perfectly for aircraft far away but not good for close as can make one plane appear to be 3 or 4. Fix this by putting another antenna up that pulses at the same time as the normal one, this pulse (p2) is weaker than the main ones (p1 + p3) if the p2 comes back stronger than the other two then transponder knows it’s hearing it’s own side lobe and discounts it |
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What flights are REQUIRED to have ads-b? What’s an encoder? There’s 2 installations of them what are they? |
IFR An encoder tells ATC your pressure altitude. They can be the blind or encoding altimeter type. The blind ones are a box seperate from your altimeter the encoder could fall out of tolerance and not agree with altimeter. The altitude encoded ones are married up to altimeter and will read the same. |
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Almost all VHF Nav receivers will handle what as well as VOR’s? Localisers have how many letter identifiers always starting with what letter? |
Localisers 4 letters always starting with ‘i’ (for ILS) |
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Almost all VHF Nav receivers will handle what as well as VOR’s? Localisers have how many letter identifiers always starting with what letter? |
Localisers 4 letters always starting with ‘i’ (for ILS) |
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How does the localiser work? What’s the special name for the positioning of where you are relative to the radio waves? |
Two transmitters on the same frequency emit waves modulated with different audio signals. One at 150Hz and the other at 90Hz. The audio signals are aligned so that they’re same strength on centreline, but one will be stronger than the other on each side of the centreline. So if aircraft is right of course the 150Hz signal is stronger and CDI deflects and shows ‘fly left’ indication. A LOCUS of points |
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How often are VOR receivers meant to be checked for IFR ops? What about localisers? |
Every 30 days Never required |
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When the CDI is being used for VOR ops how many degrees off track is one dot? What about when it’s being a LOC? Outside of how many degrees off the RWY centreline can you expect false indications from the LOC? |
2 degrees 0.5 of a degree 35 degrees |
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Where does the ILS gs aim to have the aircraft touchdown? |
About 1000ft (330m) along the runway past the approach threshold. The aircraft should pass over the landing threshold at 50ft |
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Where is the GS antenna located? Where is the LOC antenna? |
GS antenna is abeam the touchdown point on the runway LOC antenna is at the far end of the runway in line with centreline. It’s about 300m past the far threshold |
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Where is the GS antenna located? Where is the LOC antenna? |
GS antenna is abeam the touchdown point on the runway LOC antenna is at the far end of the runway in line with centreline. It’s about 300m past the far threshold |
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How many degrees is full scale deflection for: VOR? LOC? GS? |
10 2.5 0.7 |
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Where is the GS antenna located? Where is the LOC antenna? |
GS antenna is abeam the touchdown point on the runway LOC antenna is at the far end of the runway in line with centreline. It’s about 300m past the far threshold |
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How many degrees is full scale deflection for: VOR? LOC? GS? |
10 2.5 0.7 |
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How does the GS work? Which radio band? How do you tune it? Where might there be false glideslopes? |
Works on UHF frequencies Works the same as LOC except vertical instead of horizontal beams Tuned automatically when tuning the associated LLZ (LOC) frequency False slopes above, join GS from below |
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ILS signal interference may occur when? |
When another aircraft is close to either the GS or LLZ antennae. Traffic restrictions are in place around the antennae when ILS approaches are required |
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ILS signal interference may occur when? |
When another aircraft is close to either the GS or LLZ antennae. Traffic restrictions are in place around the antennae when ILS approaches are required |
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What was the MLS (microwave landing system) originally designed to do? Is it common? |
Was meant to allow curved approaches and different profiles for different aircraft. Hasn’t been well accepted and don’t know if any working |
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