Theory Flashcards
Sidebands (USB or LSB) are often used with AM radio propagation, An advantage of utilising sideband transmissions is?
a) external noise and interference are reduced
b) the carrier does not have to be so powerful
c) different information can be transmitted simultaneously on both bands
d) all of the above
D
The VOR operates on the principal of
a) frequency differential
b) amplitude modulation
c) phase differential
d) frequency modulation
C
A common error both VOR & ADF share
a) vertical polarisation
b) night effect
c) coastal refraction
d) terrain effect
D
MINTCHAT(Q) for ADF
Mountain effect
Interference (Co-Channel)
Night Effect
Terrain Effect
Coastal Refraction
Height Effect (reduced range over land)
Aircraft (Quadrantal)
Thunderstorms
AVGA(ST) for VOR
Airborne Equipment
Vertical Polarisation (When banked out of horizontal plane)
Ground Station
Aggregate Error
Site/Terrain
Advantages of direct reading compass (standard compass) over gyrostabilised remote indicating compass (RMI)
a) minimal errors, effective anywhere on the globe
b) not reliant on external power, simple construction and economical
c) output can be slaved to other instruments
d) unaffected by latitude, inexpensive and lightweight
B
VOR radials are calibrated for the magnetic variation that exists
At the station installation
Errors commonly associated with the VOR are?
Airborne equipment error
Vertical polarisation
Ground station error
Aggregate Error
Site (Terrain) Error
Aircraft bonding refers to?
ensuring an even electrical potential between all parts of the airframe
At ranges greater than line of sight, the type of radio wave which the ADF/NDB relies on to provide information is?
The ground wave, direct wave is within line of sight communication
Bending and scalloping are terms used to refer to errors in the
VOR
When you select a DME frequency you are selecting a
a) pulsed paired frequency
b) VHF phase differential between transmitter and receiver
c) VLF wave guide
d) VHF primary radar frequency
A
The ADF sense antenna?
resolves the 180 degree ambiguity
An advantage of SSR over primary radar is that the return signal
a) is reflected more strongly by the target
b) allows contouring of weather returns
c) is not subject to attenuation
d) may contain coded information
D
An advantage of SSR over primary radar is that the return signal
a) is reflected more strongly by the target
b) allows contouring of weather returns
c) is not subject to attenuation
d) eliminated unwanted returns (clutter)
D
At ranges up to line of sight, the type of radio wave propagation on which the ADF/NDB system relies to provide accurate information is
a) the direct wave
b) the sky wave
c) the ground wave
d) a combination of the ground and sky wave
AThe error of
The error or limitation commonly associate with the NDB system is
a) vertical polarisation
b) ground station error
c) scalloping or bending
d) terrain effect
D
An aircraft is being navigated solely by reference to radio navigation. The maximum permissible time interval between positive radio fixes is
a) one hour
b) two hours
c) three hours
d) a variable time calculated according to the expected tracking error
B AIP ENR 1.1 25 para 19.1.1 b
An aircraft is operating under the IFR. It is exempted fro the requirement to obtain fixes at the specified intervals when -
a) equipped with an approved area navigation system that meets performance requirements
b) it carriers a 3 member crew
c) GPS equipped
d) using VFR procedures
A AIP ENR 1.1 25 para 19.1.1 a/b
The ADF Loop antenna
Identifies the null position
HF radio waves primarily propagate by
a) ground waves
b) diffracting ground waves
c) direct waves
d) single and multi-hop waves
D
The centreline of the localiser of an ILS is determined by
A locus of points of equal signal modulation radiated from each side of the centreline
Course reversals on a localiser can occur
Greater than 35 degrees either side of the centreline
In an ILS display, full deflection of the glide path needle occurs
a) .5 degrees above or below
b) .7 degrees above or below
c) 1.0 degrees above or below
d. 1.4 degrees above or below
B
As an aircraft approaches an en-route DME station when overflying the DME readout will
The DISTANCE readout reduces at a reducing rate until overhead, and increases at an increasing rate after.
The SPEED readout reduces at an increasing rate to ZERO overhead and increases at a decreasing rate after.
The wavelength of a radio signal is defined as
The length of a radio wave from one point to the same point in the next cycle
The microwave landing system has the advantage of
Curved approaches
The nearest maximum altitude a RADALT will indicate
2500ft
Advantages of gyrostabilised remote indicating compass over a direct reading magnetic compass are
a) no errors, output can be connected to other flight instruments
b) low power operation, simple and economical
c) reliable, reduced errors and not reliant on external power
d) reduced turning and acceleration errors, reduced deviation and slaveable output
D
Advantages of a direct reading magnetic compass over the gyrostabilised remove indicating compass are
Not reliant on external power, simple construction and economical
Aircraft weather radar suffers from attenuation, therm attenuation means
Weakening of the radar transmissions and returns
The principal advantage of an IVSI over a conventional VSI is that it
a) is more accurate during a steady climb or descent
b) does not rely on air pressure from the static source
c) utilises an electrical servo system to assist in indication of climb or descent
d) utilises an inertial system to assist in indication of climb or descent
D
One advantage of a gyrostabilised remote indicating compass over the direct reading compass is
a) it is not affected by magnetic variation
b) turning and acceleration errors are minimised
c) it is not affected by magnetic influences in the aircraft
d) the complete system can be mounted behind an instrument panel
B
A flux valve for an RMI is usually located
In a remote location such as the wing
Calibrated airspeed is
IAS airspeed corrected for pressure and instrument errors, for all practical purposes IAS approximates CAS
With regard to RMI, constant oscillation of the annunciator indicates
The system is operating normal and the gyro is “hunting” about the mean position
A blocked static vent on descent will cause the ASI to
Over-read
PUDSUC for ASI
A leak in the pitot tube causes the ASI to
a) under-read
b) over-read
A
A leak in the static port causes the ASI to
Over-read when outside air pressure is LOWER than static
Under-read when pressure is HIGHER than static
An altimeter will under-read (your true altitude is higher than your indicated altitude on the instrument) when ISA is
a) colder than standard ISA
b) hotter than standard ISA
B) Hotter than standard, remember that flying an approach off the altimeter setting is and not the actual glide path indicated is a threat when temperature are colder than ISA, you are lower than indicated
The worst error in a gyro stabilised magnetic compass is
Deviation
When using a weather radar, the most turbulent areas are identified by
a) the centre of the avoid area
b) the closest contours, nearest the avoid zone
c) the position where the contours are the greatest spacing
d) the outer edge of the avoid area
B
During a descent the pitot tube of an ASI becomes blocked. As a result the ASI will?
Under-read
The ability of the airborne weather radar to distinguish between targets at the SAME ALTITUDE & (BEARING), but at different ranges (range resolution) is determined by
Pulse length
The ability of the airborne weather radar to distinguish between targets at the same RANGE and ALTITUDE (NOT BEARING, BUT RANGE) is determined by
Beam width
The maximum range of a pulsed radar array is determined by
Pulse repetition frequency
The minimum range of pulsed radar array is determined by
Pulse length
The meteorological condition which would give the maximum amount of radar energy reflected from a cloud is
a) mist
b) freezing fog
c) dry hail
d) heavy wet snow
D
Hooks, fingers and nodules as may be seen on an airborne weather radar display are primarily associated with
Hail shafts
The characteristic which has the most effect in determining whether or not a radar return will be received from a particular size of water drop is
Wave length (Operating frequency)
A radar altimeter is what kind of wave?
a) pulsed
b) continuous
A
A radio altimeter is what kind of wave?
a) pulsed
b) continuous
B
With regard to continuous wave and pulsed wave altimeters
a) pulsed wave is used for low level indication, continuous is used for high level
b) pulsed wave is used for high level, continuous is used for low level
B, pulsed wave is a radar altimeter and is used for high level indications, continuous wave is a radio altimeter and is used for low level indications beginning at 2500ft
An aircraft is descending on the glide path of an ILS, the QNH is 1013 and the temp is -15 ISA at all levels.
Assuming the aircraft is exactly on the glide path, and that the equipment is accurate and the QNH is set correctly, the altimeter in relation to the glide path would be
Above the actual glide path for that DME, if you flew the glide path as per the altitude and DME steps you would be low, as its known colder than ISA means you are lower than your altimeter indicates
If an aircraft is heading EAST over Australia suddenly decelerates, the compass reading will intitially
Turn North. SAND & ONUS
A vertical axis gyroscope at the pole, drift and topple will be?
Zero, due to earth rotation. However there may be drift and or topple due (real precession) due to mechanical friction in the bearing
A horizontal axis gyroscope at the pole, drift and topple will be?
Drift maximum due earth rotation, topple zero
A vertical axis gyroscope at the equator (any point on it), drift and topple will be
Drift zero, topple maximum due earth rotation
An aircraft is parked on the ground at a position of 30 south, all avionics and systems operating, the most correct statement with regards to the error in a directional (horizontal) gyroscope is
a) it would have no error
b) it would have half the error as in flight
c) it would have the same error as in flight
d) it would have twice the error as in flight
C, being airborne or on the ground will not change the apparent precession
A latitude compensated direction (horizontal gyro) is flown to the equivalent latitude in the opposite hemisphere, the error experienced at this latitude is?
Doubled
For accurate altitude measurements the number of (CHANNELS) a GPS receiver needs is (3D position fix)
4
3D position fix with fault detection and exclusion
6
Any of the combinations of position fix greater than a 3d position fix but with barometric aiding?
-1 satellite required
Number of satellites required to eliminate GPS receiver clock error?
4
The most significant GPS error is caused by?
The ionosphere
Use of the pseudo-random code allows
a) each satellite to transmit on the same frequency
b) each satellite to transmit on the same code
c) each satellite to transmit on both AM & FM
d) each satellite to transmit in turn
a
In the GPS, the error called geometric dilution of precision (GDOP or PDOP) is caused by
A small distance between satellites (acute angle), the wider the angle the better the triangulation accuracy
GPS works on the principle of
Time difference
The GPS pseudo-random code allows for
a) geosynchronous satellite orbits
b) powerful transmitters
c) military messages to be transmitted secretly
d) low power operation
D
The following one which is not a characteristic on the GPS (P) code is?
a) it is for use only by the US DOD
b) it can be encrypted
c) it is on a higher frequency than the C/A code
d) it is theoretically more accurate than the C/A code
C, the CA code is used for all civilian operations and is set on 1575Mhz, the P code is for military users only, can be encrypted and is on 1227 Mhz
In relation to background radio noise, the GPS signal is
Weaker
Inputs required to be entered into an IRS by the pre-flight crew are
a) magnetic variation
b) initial position
c) planned groundspeed
d) TAS
B
An IRS will accept position updates from
VOR, DME & GNSS
Flight crew using INS/IRS for navigation in CTA must advise ATC when times between updates exceed
3 hours for a single unit, 5 hours for multiple units (AIP GEN 1.5 8.3.1)
On a polar stereographic chart, meridians appear as
Straight lines
On a lambert’s conformal conical projection, a great circle track away from the parallel of origin appears
Concave to the parallel of origin
On a mercator projection a straight line represents
A rhumb line
On a polar stereographic projection, rhumb lines are?
Concave to the pole
On a polar stereographic projection, great circles are
a) represented by straight lines if they cross the pole, otherwise increasingly concave to the pole at lower latitudes
b) concave to the equator
c) concave to the pole
d) straight
A
In the northern hemisphere, the great circle track bearing decreases when flying
West <—-
In the southern hemisphere the great circle track increase when flying
West <—-
On a lamberts projection, the distance scale is expanded
Outside the standard parallels
The error associated with the NDB is
a) bending and scalloping
b) vertical polarisation
c) site effect error
d) quadrantal error
D
An NDB radiates a signal which is
Omni-directional
An NDB signal is received by an ADF in an inbound aircraft equipped with a fixed card AD, the navigation information is presented as
A relative bearing to the station
On a Lamberts conformal conic projection, a straight line is drawn from 35S 139E to the destination 38S 145E, the rhumb line track for the same trip would be
Parallel to/Left of/Right of or On the straight line track?
Lamberts conformal, rhumb lines are always concave to the nearest pole, so the track would be more north of the straight line track, travelling in an easterly direction this would leave the rhumb line track left of your straight line drawn
In a strapped down IRS, the platform on which the accelerometers are mounted is
Directly mounted to the airframe
Does a time delay, move the position of your CP?
No, only wind will move the position of your CP, or a change in power changing your TAS.
Coastal refraction is an error which results in
Bending of the NDB signals towards the coast when tracking to the NDB, or away from the coast when tracking away from an NDB. Generally at an acute angle.
If an aircraft pitot tube becomes blocked while in cruise at a constant FL, and a climb is then commenced, the ASI will
Over-read (PUDSUC), this is a climb, so inverse to the mnemonic
A Doppler VOR station has the advantage of reducing error associated with
obstructions in the vicinity of the VOR ground station
The purpose of an annunciator in a gyrostabilised remote indicating compass system is to indicate
a) that the magnetic detector unit and gyro are correctly aligned and synchronised
b) a weakening of the horizontal component of the earths magnetic field
c) whether or not the electric heading signal is being fed to ancillary equipment
d) power failure
A
A horizontally polarised radio signal (e.g VOR), is best received by what kind of antenna?
A horizontal antenna
A machmeter is subject to what errors?
PIE, pressure and instrument error
The centreline of the localiser of an ILS is determined by?
A locus of points of equal signal modulation either side of the centreline
Advantage of the gyrostabilised RMI over a direct reading compass
Can be slaved to other instruments & turning and acceleration errors are reduced due to the rigidity of the gyro, however deviation still exists to a small degree even though the remote location of the flux valve minimises this error
Which of the following is NOT an advantage of side bands (USB/LSB) in AM radio propogation
a) external noise and interference are reduced
b) the carrier does not have to be so powerful
c) different information can be transmitted simultaneously on both bands
d) the signal does not require fine tuning
D, absolute needs fine tuning, sounds horrible if its not tuned.
In an ILS display, full left to full right deflection of the localiser needle indicates a beam width of
a) 2.5 degrees
b) 5 degrees
c) 10 degrees
d) 20 degrees
B, you have 2.5 degrees either side of the LOC displayed
ILS Markers indications?
Outer = Blue, dashes 400Hz
Middle = Amber, dot-dash 1300Hz
Inner = White, dot 3000Hz
A locator in regards to an approach is?
A low powered NDB co-located in association with an instrument approach
The meteorological condition which would give the mximum amount of radar energy reflected from a cloud is
a) mist
b) freezing fog
c) dry hail
d) heavy wet snow
D, water reflects the radar return most effectively, things that are dry e.g sand, dry dirt, dry hail or ice, or clouds that don’t contain much moisture wont reflect very well. However rain causes precipitation attenuation in large amounts, and can distort an image on the radar when its heavy and dense enough.
Hooks, fingers and nodules may be seen on radar displays in representation of?
Hail shafts
The VHF band predominantly utilises what kind of radio wave?
The direct wave (space wave) [travels in a straight line with no reflection off the ionosphere like the sky wave would]
With regards to ATC SR Radar installations and weather, SSR Radar provides
a) thunderstorm avoidance guidance
b) special WX radars are needed to give WX guidance
c) guidance around storms if in the terminal area
d) secondary return of sigwx
B
The greatest error in an ASI due to compressibility is caused by?
a) high temp
b) high alt
c) low temp
c) low alt
B, as altitude increases, compressibility error increases so most error will be apparent at high altitude, think of the FO side altimeter at altitude, almost 150-200 out at FL180 on a good day
An aircraft transmitting from a vertically orientated antenna would produce a signal polarised in which orientation in what direction?
A vertically polarised signal, in a horizontal direction.
You have calculated the position of a CP of a flight, there is a revised forecast which now shows a strong headwind component in place of the previously forecast calm winds. The effect this has on the position of the CP is? And the effect this has on the time to the CP?
The CP will have moved closer towards the destination, as the CP always moves into the wind. But the time to the CP and from the CP will be the exact same as it was before the wind change.
An advantage of a laser gyro over a mechanical gyro is?
No moving parts
The number of satellites required to achieve RAIM?
5
A radio altimeter operates on the principals of?
a) continuous wave, phase, doppler, frequency modulation
b) continuous wave, phase, pulse, frequency modulation
c) continuous wave, phase, frequency modulation
d) continuous wave, phase, amplitude modulation
C, phase and frequency modulation
If an aircraft pitot becomes blocked while in cruise at a constant FL, a descent is then made, the ASI will?
Under-read
The VOR ground station transmits a signal which is
a) in the VHF band, and vertically polarised
b) in the UHF band and vertically polarised
c) in the UHF band and horizontally polarised
d) in the VHF band and horizontally polarised
D
The distance covered over the earths surface between the transmitter and the point where a radio signal skywave returns to Earth is the
a) dead space
b) reflected distanct
c) skip distance
d) critical distance
C
On a lamberts projection, straight lines approximate
a) rhumb lines
b) great circles
c) parallels of latitude
d) lines of constant bearing
B, on a lamberts the meridians converge to the pole, so as the line crosses the meridian its bearing relative to that changes, much like a great circle. This does not change the fact that great circles are concave to the parallel of origin on a lamberts
On a polar stereographic projection, great circles are approximately straight lines where?
Near the pole or over it (as a meridian)
When in CTA, an aircrat equipped with more than 1 IRS must advise ATC if the time between updates exceeds
5 hours, AIP GEN 1.5 para 8.3.1
The surface considered to provide the best return for radio alt readings is?
Choppy water, water is a great reflective surface unless it is dead flat, then it has a tendency to attenuate the return.
The components of an IRS which measure liner acceleration are
Accelerometers
When ISA is positive, an altimeter will read what in regards to true altitude?
Lower
A twin needle RMI with a needle linked to the ADF and a needle linked to the VOR (both at the destination airport) has the heading held steady, but the card is rotated manually off the current magnetic heading. What happens to the needles?
a) both needles rotate with the card
b) the adf needle rotates but not the vor needle
c) the vor needle rotates but not the adf needle
d) both needles remain stationary
C, the relative bearing to the station has not changed, therefore the ADF needle will not move from its position as the bearing hasnt changed. However the VOR needle will remain fixed showing which inbound radial you are maintaining or passing.
The frequency of a radio signal is defined as
The number of wavelengths passing in a given point in one second, frequency is expressed as Hz, 1Hz is one wavelength per second
The phase angle of a radio wave at a point one quarter though a cycle is
90 degrees
Amplitude modulation refers to transmitting information via radio waves by
Altering the amplitude of the wave signal according to variations in the amplitude of the information being transmitted
On approach to land via an ILS on the GP, the GP suddenly fluctuates, the probably cause is
Something has crossed in front of the GP, such an aircraft lining up to take off ahead of you, or an aircraft on approach to land on an adjacent runway crosses the GP.
A horizontally polarised antenna transmits a signal which is
a) horizontal in its magnetic element and vertical in its electric
b) horizontal in its electric element and vertical in its electric
c) horizontal in its magnetic and electric elements
d) vertical in its electric and magnetic elements
B
The systems which may be approved for use in Australia as RNAV systems are
TSO146/129 GNSS and IRS
The MF band predominantly utilises what wave?
The ground wave, which consists of both the direct wave and surface wave.
Where is magnetic variation applied for the ADF and the VOR respectively?
The aircraft for the ADF, and the ground station for the VOR
On a mercator projection a straight line represents what?
A rhumb line
On a polar stereographic rhumb lines are curved
Concave to the pole
On a polar stereographic great circles are
Straight if close to or crossing the pole, concave to the pole are lower latitudes
GPS selective availability is the ability of the satellite operator to degrade the signal
a) to an accuracy of 1km w/ average PDOP
b) to an accuracy of 100mt w/ average PDOP
c) to an accuracy of 10km
B
An aircraft flying a track of 330, maintaining a heading of 340 due drift passes a VOR on its RHS 55nm away, the OBS to select for a direct track to the field is?
240, drift is irrelevant for your OBS, actual track is 330, -90 = 240 inbound. We use -90 because the VOR is on our right, an inbound course would be on a westerly radial.
An advantage of single sideband (SSB) radio transmissions is?
a) Increased signal refraction
b) SSB signals do not require demodulation
c) The inclusion of a high energy AM carrier wave
d) The elimination of the high energy AM carrier wave
D
A basic inertial navigation system is gyro-stabilised to?
a) Local earth horizontal and true north
b) True north only
c) Magnetic north only
d) Parallel to the earth only
A
Why does GNSS typically require a minimum of 4 satellites for accurate positioning (assuming Baro-Aiding is not available)?
a) To provide redundancy and improve system reliability
b) To ensure availability of signals in case of satellite failure
c) To achieve 3-dimensional positioning
d) To enable the receiver to calculate the distance to each satellite using trilateral ion techniques and determine the receivers position
D
What does the tilt error in a conventional magnetic compass cause?
a) The compass to appear tilted when viewed from the side, giving erroneous readings as a result of parallax error
b) The COG to become offset from the pivot point, resulting in turning and acceleration errors, most notable at high latitudes
c) Maximum errors at the equator
d) Compass deviation, which must be corrected for by a deviation card in the cockpit
B
Which of the following is most useful for HF range
a) Single-hop sky-waves
b) Multi-hop sky-waves
c) Increased ionspheric absorption
d) Enhanced ground-wave propagation
A
The term “frequency modulation” refers to a method of transmitting information via radio waves by?
a) Varying the amplitude of the carrier wave signal according to variations in the amplitude of the information being transmitted
b) Varying the amplitude of the carrier wave signal according to variations in the frequency of the information being carried
c) Varying the frequency of the information being transmitted according to variations in the amplitude of the carrier wave signal
d) Varying the frequency of the carrier wave signal according to variations in the amplitude of the information being transmitted
D
The NDB propagates a signal by the use of which type of radio wave?
Ground Waves (predominantly)
To prevent course reversals on an ILS you should oly arm the localiser when the aircraft is within a sector of how many degrees of the centreline?
45
In secondary surveillance radar (SSR), what type of signal is sent to the aircraft and how is it displayed on the ATC screen relative to the primary radar return?
a) continuous wave, displayed separately
b) pulsed, integrated with primary radar
c) continuous wave, integrated with primary radar
d) pulsed, displayed separately
D
