Comms Questions Flashcards
111.1Mhz is a
ILS frequency
What is the time period for intial transmisision of a 406Mhz ELT?
.25s
Aircraft takes off from a 500ft elevated run way to 9500ft what is the approx max range of VHF reception
120 nautical miles
VHF Altitude range
1.23*(sure root of altitude in feet)
RNAV uses what arinc specification
Arinc 583
ILS marker lamp colours are
Outer blue, middle amber, inner white
A loop aerial has
2 null
RVR minimum for a cat 1 approach is
800m
A series tuned circuit is referred to as an ace prior circuit because
Current is maximum at resonance
I’m a class c amplifier, the transistor conducts for
Part of the time
For VHF communications freq range is
118 to 136 MHz with 25Khz spacing
Attenuation along a Hf installation co-axial feeder is due to
Skin effect
The effect of position feedback in an autopilot system ensures that the
Control surface returns to the beaut RAL position when the disturbance is corrected
Single side Andes transmission is achieved by using
Balanced modulator and mechanical filters
Glide slope transmitter operates on
UHF band
BJF and UHF makes use of the
Space wave
Audio sources for the CVR are
Captain, F/O, observer/ flight engineer and flight deck
In an aircraft equipped with mode s the sqwak code is entered
By the control panel
With radar range resolution the only possible way to discriminate separate echos is by
The difference in their delays is greater than the pulse width
111.2Mhz is
VOR
The function of the hi-Lo marker switch is to
Control the sensitivity of the receiver
The signals on a aircraft loop aerial are reproduced in the adf rx by a device known as a
Goniometer
Q-factor is a measure of
Voltage magnification in a series circuit
VOR over station sensor is activated by
Radio rate
I’m an amplifier the term stage gain means the
Gain of one stage only
The accelerometer output in a INS is
Interested twice to give distance
Typical output power of a VHF communication TX is
Between 25 & 40 watts
Decision height is the height at which a. Go around is initiatedif
Visual reference has not been established
As a transmitted frequency is reduced ionospheric penetration is
Reduced
A squelch circuit in a receiver operates the
Audio stage
When carrying out a VSWR check on a communication transmission system a satisfactory reading would be
2:1
Cockpit voice recorder provided a continuous recording of the last
30 minutes
A radars system is transmitted pulses are rated by
Average power
121.5 MHz is a
VHF frequency
112.1Mhz is
A VOR frequency
GPWS mode 2 needs
RA, rate of decent and aircraft configuration
Present position can be entered by the
FMS CDU
The azimuth angle found on the MLS system is
40 degrees
The vertical profile for MLS extends to
30 degrees
With the aircraft coupled to the flight director only when tracking of a VOR beacon
Radio deviation would be the only input
The glide path frequency is
Paired with the localiser frequency
Ok the glide path centreline the received signal is an efficient carrier modulated equally by each tone to a depth of
40%
Decca operates in the frequency range between
70-130khz
In an FD system using fixed angle capture the signal inputs are
Course error and radio deviation
In a FD system with a vertical gyro the signal from the VG
Opposes the heading error signal
If a transistor amplifier is biased to operate in class B conditions it is biased
At cut off
In ADF installations quadrantal error is maximum at
45 degrees
The VOR reference signal is
Frequency modulated
The rad alt signal is primarily used
Ok the final stages of approach down to touch down
I’m a low pass filter the attenuation band is at
Frequencies above the cut off frequency
The Jf band used for long distance communication has a
Wave length between 10 & 100 metres
The space wave
Pénétrâtes thé ionosphère and is lost into space
The phase of a modulator signal corresponds to the
Polarity of a DC input signal
If the I bar of an E and I pick off is out of datum position the
Direction of displacement gives the output phase sense.
A basic INS platform has
2 accelerometers and 3 gyros
The battery in an INS will provide emergency power for
15 minutes
The reference and variable signals of a VOR are compared for
Phase
The localiser output signals from the navigation receiver are
Polarity sensitive DC
If the input power to a 40 dB attenuator is 10 watt, the output power is
100mW
Bonding of aerials is
Normally carried out via the attachment bolts
Selcal may be used with
Both HF and VHF
The sensitivity of a radio receiver is
Normally expressed in microvolts or in decibels below 1V
The aircraft Selcal code is
Allocated by ARINC
Absorption of radio waves due to the ionosphere is the greatest in the
Day
The reflecting layers of the atmosphere rise to a high level during the
Night
A VHF receiver received signals by a
Space wave
If the length of a 1/2 wave dipole is decreased the resonant frequency is
Increased
Cat 2 RVR limits are,
800-400 metres
When flying through a VOR cone of confusion the signals used by the AFCS are
Course select error and drift angle
During an ILS landing the aircraft usually captures
The localiser before the glide slope
When would full scale deflection occur on the course pointer in a VOR
10 degrees of the beam
Precipitation static on a aircraft is due to
Flying through rain snow ice and dust
The carbon microphone
Requires an external voltage for its operation
To receive CW transmission which of the following is required
A beat frequency oscillator
The wheel height at which a go around must be initiated unless it has been visually assessed that is is satisfactory to continue the approach and landing in safety is known as the
Decision height
The runway visual range is obtained by
Multiple set of instruments at the side of the runway
The ICAO weather category 3A is
Operation down to and along the surface of the runway with RVR minima of 200m
A Dual FD system has
2 vertical gyros 2VHF receivers 2 compasses
When testing a FD in heading mode the signals needed are
Heading error and roll
To operate in RHO RHO navigation mode an installation must have
Two DME transponders
A one for deviation on the HSI is equivalent to a
75mV signal
A 1/4 section of transmission line terminated in a short circuit behaves as a
High impedance, reflector circuit
Typical impedance figuiers for a coaxial feeder are
45-75 ohms
The input impedance of a dipole is approximately
73 ohms if centre fed
The input impedance of a folded dipole is
292 ohms
I’m the glide slope mod (FD system) the signals used are
Pitch and glide slope deviation
The glide slope indication on the HSI and ADI has a typical value of
.35 degrees/dot
FD modes maybe
APPR, IAS and V/S
A marker beacon operates on a frequency of
75MHz
Radar range resolution is increased
Only with a increased PRF
ATC system transmissions are
Single channel simplex
The gain of a weather radar system is
Automatically set when altering the range selection
GNSS is made up of a network of satellites arranged
With 4 satellites in 6 orbital planes at 60 degrees
What is a negative outcome of using larger bandwidth or increased range resolution
Pulse energy is reduced
Radar receiver noise is proportional to its
Bandwidth
What factors determine the duty cycle of a radar system
Pulse width x PRF
The time taken for the return pulse of a radio altimeter is
The aircraft height and the time taken to transmit and receive plus the delay from the antenna cable length including any transceiver delay
The carrier frequency of an ILS marker transmitter is
75 MHz
A VOR RMI shows an aircraft on a heading of 030 degrees and the selected VOR radial to be 145 degrees. The relative bearing of the station is
115 degrees
When the INS is first switched on the following two actions must take place
Accelerometers levelled platform orientated to true north
When an aircraft overflies the localiser transmitter the signals received will be
In the same sense
Modulation is a process whereby
Intelligence is impressed in the carrier wave
HIRF protected areas are
Given special additional inspections to the normal airframe inspection program
If an antenna is horizontally polarised it’s plane of polarisation is
The same as it’s electrostatic field
A squelch circuit
Keeps the receiver audio off until an RF signal appears at the receiver input
The glide slope signal above the glide slope is
90 Hz amplitude modulated
The gain of an antenna is
A measure of its directional properties
To erase the tape of a CVR the following conditions must apply
Aircraft on the ground parking brake set
A IRS system consists of
No gimbals
A buffer amp on a transmitter is between
Local oscillator and modulator
A better radar range resolution is provided by
Short pulse duration
The fundamental decca frequency is approx
14.2 kHz
An aircraft in the localiser centreline received a signal equally modulated by each tone to a depth of
30%
The raw output of a the auto VOR is
Magnetic bearing information
A minimum distance over which communication at a given frequency can be established by means of the sky wave is known as
Skip distance
The ins system is Schuler tuned to prevent errors due to
Oscillations if the platform due to aircraft accelerations
The external inputs to an ins are
TAS and altitude
The radiation pattern of a VOR station will transmit bearings that are
Magnetic
The characteristic impedance of a transmission line is
Independent of length
To meet the requirements of HIRF protection gold film windscreens need
No additional protection measures
HF wire aerials should not be made of stainless steel because it has
High RF resistance
An aircraft transmitter has an output impedance of 50 ohms the correct matching for this transmitter would be
Feeder 50 ohms
Aerial 50 ohms
The ideal standing wave ratio in an antenna is
1:1
After VOR capture on a ground check, aileron movement will depend upon
Course select error, radio deviation and bank angle
The outputs from a balanced modulator are
LSB AND USB
FM systems are less affected by noise than AM systems because noise modulates the carrier in
Amplitude
The facility performance ILS intersect height is where the
Localiser and glide slope signals cross
Crosswind compensation in an FD system may be achieved using
An integrator
After go around in an FD system the following mode may be selected
HDG
The bandwidth of an antenna
Can be increased by using a matching sub
An interrupted carrier wave is referred to as
A1
A DME system gives
Slant distance
Radio altitude is annunciated by voice
Below 500ft
ATC mode c uses
Gilliam Gray code
The three transmitted omega frequencies are
10.2 kHz, 11.33 kHz and 13.6 kHz
An aircraft is due south of a VOR beacon and has 000 degrees set in the omni- bearing selector if the aircraft is heading 090 the time from indicator will show
To
The INS battery is used to
Start the system and run it in an emergency
The usable range of the ILs beam is
About 15 miles greater than the glide slope
Side tone can be derived from the transmitter
Power amplifier
A single side and transmitter is transmitting in the upper sideband the carrier frequency is 10Mhz the modulating frequency is 10 kHz the transmission will consist of
A single frequency of 10.010Mhz
The ground run monitor present information of
distance to go and ground speed
An aircraft at 40,000ft using vhf can communicate upto a distance of
260NM
A VOR ground station is referenced to
Magnetic north
A dipole for operation T 300 MHz would have a length of
500cm
When the heading knob is rotated ok the FD system it moves the rotor of a
Control transformer synchro
A class 3 fault reporting failure
Has no consequences on aircraft safety
How many gps satellites required to locate the aircraft’s position in 3 dimensions
4
With a magnetic indication of 000 easterly deviation would
Be added to the heading as easterly deviation is positive
A cvr installed on a helicopter first certified after 1st august 1999 with two engines with a max certified MtOW 3175KG must begin recording
As early as possible during the cockpit checks prior to engine start
A CVR is found to be unserviceable
Flights must not continue after 72 hours
A defective radôme would cause
Excessive ground clutter
A DGPS system installed on a aircraft requires
One ground station and 4 satellites
A DME system indicates aircraft
Slant range to the beacon
A DME is in auto standby when
The DME receives 300-400 pulses a second
A DME receives a ground transponder reply after 2472 micro seconds the slant range to the transponder is approximately
196nm
A Doppler radar antenna is moved
Automatically to track
A Doppler a VOR stations transmissions
Can be received and processed with a conventional VOR receiver
A flat plate antenna is a
Series of slots and wave guides
A force rebalance accelerometer in an in system has the acceleration force balanced by a
Linear force
A GNS satellite system transmissions are
Right hand circular
A GPS system is formed from
Space control user
A hyperbolic system is
LORAN C
A laser dither mechanism ensures that
Optical back scatter does not cause the contra rotating beams to lock together
A laser gyro output is
Directionally proportional to angular turning rate
A LORAN C transmission consists of
8 pulses each 270 microseconds long
A magnetron can be used as an
Oscillator or an amplifier
A mode S transponder utilises a
Logarithmic amplifier
A mode C transponder
Can be used by TCAS
A mode C transponder gives the following information
Altitude
A mode S equipped aircraft has its RA area breached by a mode A only equipped aircraft what warning does the mode S aircraft get
TA visual and aural traffic traffic
A mode S transponder makes a mode A/C only call, what is the length of the P2 pulse
.8us
A moving coil microphone needs
No power supply
A padder capacitor has most efficiency at
The lowest frequency of the L O
A poor oscillator in a receiver would cause
Poo channel selectively
A pulse repetition frequency of 1000 transmits for 2 microseconds the peak power is 1 kW the average power is
2 watts
À quartz crystal has the characteristics of a
High Q resonant circuit
A rad alt trip signal is
Switched DC
A rad alt in track mode is effective to
2500ft
A radar antenna is facing left on ground test if you move the vertical gyro to simulate a right bank the antenna
Will move down
A radar response takes 329 microseconds how far away is the target
25 miles
A radar pulse takes 308 microseconds to return wheat is the target distance
Approx 25 miles
A radio frequency of 16 MHz would be used for
HF comms
A radio signals chance of penetration of the ionosphere
Increase with frequency
A rain fall of 5mm/he is indicated on the WXR by a
Yellow colour
A received acars message is
Via the on vhf receiver
A receiver having an IF of 465 kHz is tuned to 1300KHz which of the following signals could interact with the LO second harmonics to produce a receiver output if no RF amplifier was used
3995KHz
A receiver in which selected signals of any frequency are converted to a single frequency is called a
Superhet receiver
A receiver with a high IF will successfully reject
The 2nd channel / image frequency
A receiver with a large bandwidth will have
Poor signal to noise ratio
A resistance-capacitor low pass filter will have
The output taken across the capacitor
A Schuler pendulum has a period of oscillation of
84.4 minutes
A secondary radar system receives reply signals from
Another transmitter
A SSR interrogation operates on
A frequency of 1030MHz and pulse spacing depending on mode of interrogation
A Selcal signal transmits
Two pair of tones one pair after another
A signal at 120 MHz frequency will normally propagate by means of
Space waves
A single side and transmission is equal to
Low level modulation
A strap down INS has
A solid state accelerometer system
A TCAS blade antenna is
Part of the atc transponder system
A transponder that is compatible for use with a TCAS system would be
Mode S
A triple rad alt installation isolation is carried out by
Differentiating the frequencies
A valid interrogation will
Disable the RX, enable the encoder and disable the DME
A VHF comm blade aerial has a length of
A quatre wave length
A TCAS blade antenna is
An L-Band omnidirectionnel array
A whip antenna uses
1/4 wave
Above the glide slope the ILS glide slope signal modulation is
90Hz
ACARs is
A way of reporting defects to maintenance base in flight
ACARs is primarily used for communicating with
Maintenance base
ACARs is used to transmit
Both in flight and on the ground
ACARs sends information from base to the aircraft via
The printer
ACARs system operates in the frequency range of
131.550MHz
ACARs transmits it’s data using
Binary code
Accuracy if a GPS system used in aircraft navigation systems is
16 metres or less
Adding 6ft of cable to both TC and RX aerials on a rad alt would give you
18ft error
ADF is
Theta
(Angle only)
ADF operates within which frequencies
200 - 1000KHz
ADF operation range is at
MF band
ADF system sense aerial is
Null cardiod
ADF works by using
Both loop and sense aerial
Aerial masts maybe be damaged by
Skydrol hydraulic fluids
Aerials provide optimum output at one particular frequency when it’s load is purely
Resistive
After flying through the cone of confusion
Signal alters and the instrument indicates from
After passing the cone of confusion of a VOR
The phase difference reverses
Aircraft is 9000ft when is out of VHF range?
120NM
Aircraft north of VOR beacon on a course of 090 RMI the pointer points to?
180
Alert and decision height differ in that
The alert height is based on ILS equipment and decision height is based on the RVR
Alert height is
Where a decision of whether to land is made based on aircraft characteristics and it’s fail operational landing system
Align light flashes during alignment of an INS
It is attracting the operators attention
An o ring in a wave guide is used to
Stop moisture entering the wave guide
An accelerometer has
High inertia, restrained
An accelerometer in an ONS must be able to detect accelerations down to
10-6 g
An ADF system includes
Both a sense and loop antenna
An adjustment of the laser beam inside a laser gyro IRU
Can be done by adjusting the servo mirror
An aerial can be broadbanded by
Using a stub
An aircraft equipped with Mode A transponder only, enter airspace of a TCaS 2 aircraft. What indication does the pilot of the TCAS 2 aircraft get
TA after ranging
An aircraft flying on a heading of 030 receives an ADF signal 030 relative to the aircraft what is the ADF pointer indicating
060
An aircraft is on course on an IlS localiser what is the difference in depth of modulation (DDM)
Zero
An aircraft receives response from a DME station, 1236 microseconds after transmitting the interrogation. What is the slant range to the station
96 nm
R=(T-50)/12.359
An aircraft with 8.33kHz separation vhf communication system communicates using
Single channel simplex
An autoland can operate without an autothrottle if
The control of the speed does not create excessive pilot workload
An electromagnetic microphone requires which type of input
None
An FM signal would have its side and signals
No sideband present
An hf coupling is used to match the
Aerial
An I F amplifier unit consists of four amplifiers the amplifiers are normally coupled by
Transformer coupling
An ILS back bean approach uses
No glide slope
An IN system requires data from the
Air data computer
A IN unit uses pin programming for
Location
An IRS alignment
Takes 10 minutes and present position can be entered anytime during the alignment
An IRS cannot calculate
Local longitude
An isotropic radiator
Has a perfectly spherical radiation pattern
An over station sensor OSS detects
The rapid rate of the VOR signal over the cone of confusion
An OSS is triggered by
Rate of change of radio deviation
An RMI in VOR mode, it’s pointer is showing a course 000, if the course knob is adjusted to 010 what happens to the pointer
It will not move
Anti cross-talk network for unwanted signals use
Attenuation first the amplification
ARINC 629 operates at what speed
2000Kb/s
At its resonant frequency a parallel tuned circuit
Has maximum circulating currents
At its resonance frequency a parallel tuned circuit has
Maximum impedance
At resonance in a series tuned circuit the impedance is
Low
ATC altitude read out is
Series transmitted with binary encoding
ATC transponder uses what frequency band?
UHF
ATCRBS reply pulses are
0.45us wide
Attenuation in a coaxial cable
Increases with frequency increase
Attenuation of ground waves
Increases with frequency
Audio frequency range is
20-20,000Hz
Audio select panel voice switch
Allows Nav and ADF through
Back bean is captured
By manually selecting the back beam mode
In MLS the 12 but preamble consists of
5 bits time function and carrier and 7 bits function
Bandwidth of HF transmission is
3kHz
Before processing an AM USB signal, what needs to be done
Carrier added
Before the aeroplane is moved from the loading pier, the pilot must
Insert the latitude and longitude of the pier into the INS
Before the SSB is demodulated
The carrier wave is reinserted
Carbon microphones require
DC supply
Centripetal error compensation is achieved by
An additional signal is added to the N/S accelerometer to cancel the centripetal error
Channel 3 on a CVR records
Flight deck
Coaxial transmission line of impedance 80 ohms is connected to a dipole of 120 ohms. While checking with an ohmmeter the reading will be
More than 20 megaohms
Communication between the aircraft earth station and the satellite is on
L band
Confirmation of the correct operation of an ATC transponder ident function is verified by
Use of a ramp test set
CDU selection of TKE displays
Difference in degrés that the aircraft track is to the right or left of the desired track
Coriolis effect is corrected for by
Adding a correction term to the accelerometer outputs
Crystals operate reliably at fundamental frequencies up to
30MHz
CVR is unserviceable
The aircraft can fly for 72 hours since unserviceability
Data communication between the aircraft and the operational control centre is possible through
ACARs system
Decca navigation usés
LF
Delayed automatic gain control is inop, the sensitively of the receiver will
Increase for the high voltage signals
DFDR arinc 573 data bud has how many subframes
4
Differential GPS requires
4 satellites and 1 ground based transmitter
Direction property is exhibited by
The loop antenna
DME compares what for measurement of slant distance
Pulse transmission and return echo
DME interrogation is carried out
63MHz above or below transmitted frequency
DME reply pulses are 63 MHz
Higher or lower
DME squatter comes from
DME station
DME transponder transmits on receipt
Of a pair of pulses separated by 12 microseconds
DME uses which frequency band
UHF
Doppler flag comes on when it receives
No signal
Doppler navigation uses
No ground based equipment
Doppler VOR, when received by a conventional VOR receiver
Has normal reception with an ident signal
DSR TK means
A great circle path on surface of earth connecting two way points
During ACARs transmission a 1 is generated by
A 2400 Hz waveform
During ATC transponder operation suppression acts to
Mute the DME operation during the transmit phase
During initialisation ins used to calculate local vertical
Accelerometers only
During operation of a twin HF radio system transceiver
No 1 hf system operation is inhibited during no 2 operation
During testing of ATC altitude function the pressure altimeter is set
1013.25mb
Earth rate is approx
15 degrees an hour
Emergency frequency is
121.500 MHz
EPR and speed for autothrottle is activated at
Take off
Flight director on GS capture the pitch Integration is to
Decrease GS error signal
Flight director on VOR, course error wash out signal is lost when following the FD commands aircraft will
Follow the course with scalloping or bracketing
Flight management control system utilises
ILS, DME, ADC
FM improvements affect what system
VHF, VOR, ILS
FMC changes movement via
Flight control computer
FMC mode that can be selected through the CDU is
CRZ
FMC provides data envelope for
GPWS
FMC secondary flight plan is selected
In the air by the pilot
FMCS outputs to
GPWS
For radio communication over a distance of over 250nm we use
HF
For INS the battery unit provides standby power
Both when airborne and on the ground
Frequencies used for MLS are
5-5.1 GHz
Frequency modulation used for transmission of audio signals is best suited to
Short range transmissions
From where is bearing information received for display on the digital distance radio magnetic indicator
From VOR and ADF systems
Full scale deflection of the glide slope pointer from the centreline is
.7 degrees
Full scale deflection on a VOR system is
10 degrees
Function of ADF VOR and DME in navigation system with reference to aircraft and beacon is
The first provides bearing line from aircraft to beacon and latter provides distance between aircraft and beacon
Glide slope deviation signals are
SC polarity sensitive
Glide slope frequency is
328.6 - 335.4 MHz
GNSS is
Any satellite system that provides autonomous geospatial positioning with global coverage
GPS
Uses 24 satellites equally spaced around 6 orbits
GPS antenna is
Circular polarised
GPS consists of 24 orbiting satellites located
I’m a 10900 nm high orbit
GPS frequency is
1575 MHz
GPS has
4 satellites in each of 6 orbits
Gos L1 and L2 signals are
Biphasé 50 bit/sec
GPS receiver navigation message frequency is
50 Hz
How sends L1 and L2. What is on L1?
C/à code and p code
GPS telemetry consists of
Satellite position Information
GPS works on the principle of
Information received from satellites is cross referenced against other signals received to calculate position
GPWS will show a fault if the following fails
Radio altimeter
Group countdown in a transponder receiver changed the
Sensitivity
HF aerials have weak points designed at
The back end
HF communication frequency is in the range
3-30MHz
HF transmission of 10 MHz with a sideband of 1000 Hz which drifts 50 Hz the received audio tone would be
1000Hz
How many bits make up the Mode S address
24
High range resolution is obtained by
Shorter pulse width
How can it be verified if FMC updates is correct
FMC via CDU
How does a receiver know whether an ILS or a VOR frequency has been selected
Logic control circuit in the control unit
How does an aircraft distinguish its own DME equipment reply from this for other aircraft
By changing at random the time delay between the pulse pairs of the interrogation signal
How does irs calculate velocity
Integration of accelerometers
How does the flight director computer differentiate between VOR and ILS frequencies
Frequency discriminator in receiver
How is a DME station identified
Morse
How is the flight deck informed of an acars transmission
Double chime
How is the next database on the FMC activated
Manually on the ground
How is the glide slope frequency chosen on the nav control panel
It isn’t manually chosen it is paired with the localiser frequency
How long does the gps éphémères collection take?
30 seconds
How long is the time between the start of the P1 pulse and the P3 pulse for a mode A transmission ignoring the P2 pulse length
8 micro seconds
How long is the time beteeen the start of P1 pulse and the P3 pulse of a mode C transmission ignorning p2 pulse length
21 microseconds
How many aerials are there in a TCAS system
2
How many databases are required in an FMS system
2
How many programs can a FMC store
2 one active one standby
How many satellites are required for GNS
4
How many satellites compromise the space segment for GPS
4 satellites in each of six orbits
How many times does the ins integrate the acceleration signal it receives from the accelerometers to get the distance the aircraft has flown
Twice
How would you increase radar target range
Low PRF, high scan and long pulse duration
Hyperbolic navigation uses the principle of
Time difference or phase difference between two radio signals depending on which type is used
If a ground station interrogating an aircraft transmits P1, P2 and p6 through the rotating beam antenna and P5 is radiated by omnidirectional antenna, which mode is it addressing
Mode S only
If a VOR RMI indicates 000, and the course selected is 000 what will the to/from indicator display
To
If an 80ohm coaxial cable is connected to an 80 ohm dipole aerial resistance would be
80 ohms
If an aircraft is east of VOR beacon the reference and variable phases are
Phase quadrature
If an aircraft is flying on a heading of 000 away from a VOR station the to/from indicator would show
From
If an FM signal is modulated by an audio signal the frequency of the audio would relate to the
Rate of the frequency change
If faded totally fails the pilot will get
A light illumination on the fadec control panel
If one FMS fails in a dual system
FMS CDU on fail side goes blank
If one FMS fails in flight
The standby FMS takes over
If radar pulse is reduced there is
Reduced relative range
If the 90 Hz tone predominates in a localiser receiver the deviation indicator will show
Fly right
If the ADF cable is to long
Secure and stow excess cable
If the battery fails on a in’s system in the ground
An amber light appears on the MSU and a horn sounds
I’d the inductance in a parallel tuned circuit is increased in value the resonant frequency
Decreases
If the runway picture I’m the EADI moves down during an ILS approach the aircraft must fly
Down
If the VOR track error is 2 dots how many degrees off track is the aircraft
10 degrees
If two aircraft decide to issue the same RA for a potential conflict which aircraft changes the decision
The one with the higher address
If you carry out a VSWR check of a SSB HF system what should you do with the control switch? Select it to
AM
ILS and VOR operates in which range
VHF
ILS marker beacon lights are
Blue, amber, white
In a colour wxr AGV is set
Automatically on receiver noise level
In a CVR system hot mics
Is a term applied to all the aircraft’s mics
In a DME system how does the receiver fine the recorded pulse pairs are valid
Decoder
In a Doppler system the frequency return of the forward beam will only match the rearward beam
During level flight
In a Doppler VOR the 30Hz reference signal is
AM modulated
I’m a dual FMS a failure of one computer will result in
No effect on the CDU
I’m a gimbal system the stable platform is the
Azimuth gimbal
I’m a gps system what type of clock is in the receiver
Quartz
I’m a ground wave which plane of polarisation suffers the greatest attenuation
Horizontal plane
Ina large transport aircraft to check VSWR of a HF system with a long aerial feeder the VSWR meter has to be connected
Between the transmitter and the ATU (ATU End)
In a loran nav system master station transmitter frequency
The same as the slave
Ok a modern aircraft the acars system is used primarily for
Comme between the aircraft and base
In a rad alt system if you decide to increase the tx cable and rx cable each by 3” the total correction factor is
9”
In a secondary radar system at what frequency does the interrogator transmit on
1030MHz
In a superhet receiver the advantage of an RF amplifier is
It improves signal to nose ratio
Ina triple rad alt installation on a large aircraft interference is prevented by
Varying the modulating frequency of each system
In a universal all call transponder interrogation P2 is indicated by the
Omnidirectional antenna
In a vertically polarised electromagnetic wave
The electric field vectors are vertical
I’m ACARs in an upcoming message is received
A chime sounds in the cockpit
I’m ADF quadrature error are eliminated by placing attenuators
Across loop aerial
I’m an ADF system the goniomètre
Effectively simulates a rotating loop antenna
In a VOR receiver
30Hz modulated reference signal is compared with 30Hz variable phase signal
I’m a AM wave the intelligence is contained in the
Sideband only
In a analogue radar what’s is the purpose of a balanced mixer
To improve noise reduction factor
In a autopilot A.C analogue computer VOR deviation signals before integration with course error signals are
Modulated
In an In system the output of the accelerometer is linear because of a
Force balance system
I’m a IN system the purpose of the stable platform is to
Prevent unwanted acceleration affecting the accelerometers
In an INS system the accelerometer is a mass
Suspended between two springs in a tube
I’m a interrogator mode S addressing format when does the first synch phase reversal occur
2.75u seconds after P2
In an IRS system you would expect to find
Ring laser gyros
I’m an IRS system the accelerometer is double inter grated for
Distance
I’m sera navigation a line of constant bearing would be define as
Rhumb line
In audio clipping
Vowels are attenuated relative to the remaining signal
In CVOR 9960 c/s AM subcarier is used in the
REF phase
In Doppler radar with a moving aerial the aerial
Turns automatically to match the aircraft track
In flight mode the FMS preference data source is
IRS, RHO-RHO, RHO-Theta
In ground mode the FMS uses which of the following for velocity calculations
IRS
In ILS the glide slope provides
Vertical steering
I’m INS vertical acceleration is calculated by
An accelerometer
I’m LNAV mode
The pilot can change heading from the MCP
I’m MLS what is the beam angle away from runway
15 degrees
I’m regard to the aircraft transponder what is the pulse frequency
Amount of times reply signal is sent per second
I’m the downlink DF11 format a .5 microsecond pulse in the first half of the slot represents
A logic one
I’m the LORAN nav system the master station frequency in relation to the slave frequency is
The same
I’m the OBMS the printing report system is activated
Either manually or automatically
In VHF comms with 8.33 kHz spacing how many channels are used
2280
I’m VOR the manual phase shift resolver is a
30Hz signal
In weather radar short range targets are missed by
Larger pulse width
In what frequency range does the ADF system operate
190 - 1759 KHz
In what type of Doppler system do altitude holes appear
FM and pulse
In yagi array antenna the signal is fed through a cable to
Dipole
Incompatible FD modes are
Altitude hold and ILS
Increasing the bandwidth of a radar receiver
Has no affect on pulse shape but increases noise
INS has mercury switches on
All gimbals
INS power is provided by
AC normal
DC emergency
INS wind speed is calculated from
The vectorial addition of TAS and GS
IRS obtains basic position information by
Inter grating twice the accelerometer output
IRS serviceability for in service drift is ascertained by
3+3t
Janus in Doppler radar
Adjusts for lateral and vertical steering
Janus operation is used
For better coverage
L band DME transmits on a frequency of
1090 MHz
Laser gyros
Do not have rotational parts
Laser gyros are
Aligned to the aircraft structure
Laser gyros have
Moving parts
LOC modulation is
20%
Localiser beam width is the angle where the two edges of beam are apart at the runway threshold by
700ft
Localiser modulation depth is
20%
LORAN C uses
100KHz
Man made noise causes interference
Mainly below 12 MHz
Marker beacon receivers have
No control unit as the unit typically turns on when the avionics master switch is activated
Marker information is usually provided to the pilot
Both visually and aurally
Maximum power on a wave guide is governed by the
Narrowest width
MLS elevation coverage is
15 degrees
MLS operates on what frequency
5031-5090.7 MHz
MLS are modulated with
Phase shift keying
Mode 4 of GPWS derives warnings from
Rad alt decrease
Mode C response is
20.3 microseconds
Mode S pulses which are used
S1 p1 p3 p4
Mode S transponders transmits a binary code of
24 bits
Most aerials are
Bonded
Most radio aerial masts are
Bonded
Omega ground station transmits
Pulses of CW
On a back bean approach which error signal would not be used
Glide slope
On a fibreglass aerial what paint should be used
Not cellulose
On a WX radar display the time base is a
Trapezoidal wave form
On an aircraft comm system HIRF interference is most prominent
At specific frequencies
On an FMCS CDU you can select
N1 thrust
On an HF radio set the clarifier control is used
To adjust the reinserted carrier due to instability in the RX
On a ILS approach what will cause the aircraft to fly onto the beam
Radio deviation
On a RMI the input to the ADF pointer is fed via
A synchro
On power up the IRS obtains position
Longitude from last position
Ok TCAS with own aircraft below 1750ft
Any other aircraft below 360ft are deemed to be on the ground
I’m the ASP how many RX and TX can be selected at any one time
Multiple RX and only one TX
Ok the ATC radios readability scale what is satisfactory reception
5
Outer marker frequency is
400 HZ
Overshoot or go around mode can be Initiated
After glideslope capture
Peak power is 10 kW pulse period 6us and duty cycle is 2.4ms. What is the average power transmitted
25w
Pin programming is allowed
To provide reference to FMS computer as to which side of datum it is fitted to
Precipitation static is caused by
Skin to air particle collisions
Rad alt failure effects which system
GPWS
Radar resolution is the ability to determine between
Two targets in close proximity to each other
Radiated interference of current carrying cable can be minimised by
Putting the affected cable in a single conduit
Rad alt normally indicates the altitude of
0-2500ft above ground level
Radio switches are normally
Spring on R/T latched on I/C
Radio waves are said to have mine of sight propagation
Above about 100MHz
Random precision of the inner gimbal ring is detected by placing mercury switches
On inner gimbal ring
Range resolution in a radar system is improved by
Shorter pulse
Restrictions to the use of hand held mics apply to
Transport category aircraft only
RMI in ADF mode the pointer is moved by a
Loop voltage
RNAV accuracy is
+_ 5nm 95%
RNAV system uses
VOR gps
RNAV uses which inputs
IRS
VOR
GPS
DME
Satcom carrier signals suffer from a Doppler shift of frequency due to the
Velocity of the aircraft with respect to the satellite
Satellite transmits updates on every
2nd orbit
Second Chanel Mmmm interference could occur if the IP frequency was at twice the
I F and on the opposite side of the local oscillator frequency
Selcal is used to
Monitor ground signals
Selection of the INS mode selector unit to ATT REF is made
When navigation information is lost
Short duration radar pulses
Allow echoes from short range
Single side band filters are
3kHz
Slewing of the INS gimballed platform simulates in flight attitude changes up to
71 degrees in pitch and 180 degrees in azimuth
Sonar location beacons are a
ICAO requirement
Standing waves in a coaxial feeder cable are proportional to
Degree of mismatch between transmitter and antenna
Suppressor line is required for
All L band equipments including TCAS
TCAS considers another aircraft to be on the ground at a difference height between the barometric altimeter and rad alt of
180 ft
TCAS transmits squirted pulses on a frequency of
1090 MHz
TCAS antenna is a
Directional antenna
TCAS 2 is
24 aircraft per 5nm radius
TCAS is selected
By a switch by pilot on selector panel
TCAS transmits interrogations and receives replies on a frequency of
1030 MHz & 1090 MHz respectively
TCAS will issue a TA if
A collision is within 35-40 seconds of occurring
The aerial element of a vhf comms transmitter / receiver should have a mid band length of
N/4
The aircraft equipment determines the bearing of a ground station by comparing
The phase of two 30Hz modulations
The aircraft is due north of the VOR station on a heading of 90 what is the RMI displaying
180 degrees
The alignment position of an IR mode selector unit enables
Gyro run up, levelling azimuth determination
The anti skid armed signal comes from
A switch in the cockpit
The approximate distances of the middle marker from the runway threshold is
3500ft
ACARs uses which frequency band
VHF
ATC antenna has a polar diagram which is
Directional
The ASP allows crew to
Transmit on one channel listen on multiple
Auto gain voltage of a weather radar is set
By the manufacture
Autopilot disconnect indications are
Flashing master warning light and an aural
Aviation distress frequency is
121.5MHz
The bearing of a NDB measured by ADF is 060 relative to aircraft heading of 030. The RMi pointer indicates
90
The components of an ILS system are
A localiser glideslope and Marker beacons
The correct sense demand generated for a selected heading 180 when the aircraft heading is 150 is
Turn right
The crab angle of the aircraft during VOR or LOC modes is displayed by the
Difference between the course arrow and aircraft heading
The crew select DH on
The rad alt display
The delete tone button on a VOR/ILS test set is for
Testing correct operation of the flags
The distance over which VHF comms may be achieved is limited
To radio line of sight
The Doppler VOR beacon reference signal
Solitude modulâtes the carrier frequency
The DVOR is preferred in comparison to CVOR because
DVOr is relatively insensitive to site errors
The electrical tuning unit of an Hf transmitter maintains a VSWR of the antenna at
1.3 - 1
The FFR ULB operates at a frequency of 37kHZ
With an operational time of at least thirty days
The flight director is on a localiser when the radio deviation signal is lost the aircraft would
Fly parallel to the localiser
The FMS navigation database is updated
Every 28 days
The frequency of 111.1MHz is used by
ILS localiser
The frequency of a glideslope transmitter is
328.6 to 335.4MHz
The frequency range 300KHz - 3MHz is called the
MF band
The frequency spectrum of noise is
Infinitely wide
The fundamental theory of operation of a ranging radar is
Time take to receive returns
The general function of the ATC transponder is to
Reply with an identification signal after being interrogated by a ground station
The glide slope and localiser frequencies
Are paired and one frequency sleeve for suffices both
The glide slope equipment operates in the
uHF band
The glide slope in an ILS provides
Vertical references
The glide slope system offers approach guidance to the runway in terms of
The vertical plane
Glideslope transmitter is located
Adjacent to the touch down point of the runway
GPS provides location and time information when there is unobstructed line of site to
4 or more satellites
GPS satellite system consists of
21 satellites and 3 standby satellites
Ground run monitor presents
Ground speed and distance to go
The heading error signal used in the heading select mode
Is the difference between the desired heading and the actual heading
The horizontal angle contained between the true and magnetic meridian at any place is
Declination
The image channel ratio is
Response at wanted channel frequency over response at image channel frequency
The impedance of an hf aerial is
50 ohms
INS computes distance from acceleration by
two successive integrations
The input data for the RNAV system comes from
Existing systems within the aircraft and dedicated rnav transmitters
The ins platform is
Always parallel relative to the earth surface
The IRS laser gyros is a
Rate gyro
Janus beam is for
To compensate for attitude changes
Laser ring gyro
Does not have a gimbal
The length of a resonant antenna dipole is
Lambda/2
Localiser deviation signal for the flight director comes from the
VHF nav System
Localiser looks after
Horizontal plane
The loop aerial polar diagram is a
Figure 8
The manual input for the VOR course corrector is related to
The C.D.I. offset bar
Middle marker beacon is
Amber
Middle marker modulation is keyed with
Alternate dots and dashes
MLS frequency band is
C
Mode S squirted pulse will
Contain aircraft identity
Mono pulse aerial system is used to provide TCAS with
Bearing information
Most common type of gyro used in ins is
Single rate integrating gyro with viscosity damping
Most sensitive system between ils and VOR is
ILS
Noise factor of a receiver whose I/P signal to noise ratio is 15:1 and O/P signal to noise ratio is 12:1 is
1.25
Number of different radials provided by a ground station is
Infinite
Number of VHF frequency channels is
760
Output of an ins can be fed to
Attitude indicators
The path of a point which moves such that the difference in a distance from two fixed points is equal is called
Hyperbola
Plane of polarisation is defined as the plane in which the
E field lies
Polled mode in a acars
Operates only when interrograted by the ground facility
Polythene coating on an hf antenna wire is provided
To prevent precipitation static build up
Polythene sleeping over a hf antenna is to stop
Precipitation static
Preferred location of a VOR antenna in light aircraft is on
Top of the vertical stabiliser
The pulse reputation frequency should be
Low for long ranges
Quadrantal error in ADF is maximum at a heading of
045
Rad alt electrical length for a helicopter of cable length 18ft is
28ft
The radar is set to long pulse bursts this will have the effect of
Missing close echo returns
The range at which the STC waveform ends is proportional to
Pulse width
The rate of G/S warning I’m GPWS
Changes with radio altitude
The RF resistance of an inductor
Increases as frequency increases
The short circuit stub that is used for B-road banding a VHF whip antenna for frequency of 127MHz must have a length of about
59cm
The stability of an effort oscillator can be improved by
A buffer amplifier
The system which will be inhibited during a radio altimeter self test is the
GPWS
The term oblate spheroid refers to
flattening at the polar regions
The term HIrF
High intensity radiated fields
The three accelerometers on a stable platform are mounted
Orthogonally
The three accelerometers on a strap down platform are mounted
90 degrees to each other
Tone frequencies for glide slope and localiser are
90 and 150 Hz
The transmission lines normally used between a radio antenna and its transceiver equipment is
Coaxial cable
The type of gyro generally used in an IN system is a
Rate integrating gyro
The uplink 11 format uses
Differential phase key shifting
The VHF aerial resistance and transmission line resistance is
50 ohms
The voice switch on the ASP has a
1020KHz band stop filter
The VOR system compromises
Variable and reference phase signals
The VSWR of a VHF system with a forward power of 100W and a reflected power of 4W will be
1.5:1
There are two FMS in an aircraft which are
Master and slave
There are two FMS installed on the aircraft if one fails during flight
The failed FMS has a blank screen
Three RF amplifiers of 10 dB and 10KHz are in cascade what is the output
30dB and 10KHz
Time base of PPI display is
A trapezoid
To carry out a database update ok the FMS
Use the database loader
To check side lobe suppression
Use a ramp test set
To improve the image or picture when using the WXR
Use shorter bursts
To know the valid database on the FMS
Call up the relevant CDU page
To make a passenger announcement from the flight deck
Set the asp to PA and transmit from the control column
To minimise cross cable interference
Run radiating and affected cables as separate bundles
To obtain an accurate GPS fis the GPS receiver must be in line of sight of
4 satellites
To prevent gimbal lock on the stable platform is is normal to use
4 gimbals
Track error is the difference between
Actual track and desired track
Track mode of an rad alt is operational
From 0 - 2500ft
Transmission line losses have what effect on VSWR
Do not affect
Transmitter aerial radiates
Electrostatic and electromagnetic energy
Transport rate compensation is achieved by
The platform being torqued by a computed torquing signal
Tx output stages are normally run in class c
Because the efficiency is high
Types of very low frequency navigation include
Decca oméga
Use of a diplexer in a receiver is
To enable signals to be distributed to different receivers
Using INs an aircraft flies
Great arc circle
VHF air and frequency range is
108-136MHz
VHF antenna length is based on
Quatre wavelength
VHF frequency is
30-300MHz
VHF transmitter output impedance to match with antenna for maximum power transfer is
50 ohms
Voice clipping
Decreases the depth of modulation of high amplitude voice signals
Voice selected from the voice range switch on the ACP acts as a
1020Hz band stop filter
Voice/range switch selected to range
Allows nav/adf and DME through and cancels out voice spectrum
Voltage buffer amplifiers are used when
An impedance change high to low is required
VOR capture can be determined by
A predetermined level of the VOR deviation signal away from the selected radial
VOR left right deviation signals come from the
VHF nav set
VOR washout signal is by
An integrating circuit
Wave length of X band radar is
3cm
What are the shapes of traffic shown on a TCAS display
White diamonds, red squares, amber circles
What close is used in a gps satellite
Atomic
What does 7700 Indicate on the ATC panel
Emergency
What does decca navigation system operate on
Low frequency
What does a diplexor do
Channel to RX
What does INS calculate on power up
Latitude
What does the radar contour button do
Alter the video amplifier
What frequency are VOR and ILS
VHF
What frequency increases radar relative range
Low
What frequency range does acars operate on
118-136MHz
What happens if frequency decreases without altering physical length of aerial
The aerial becomes capacitively reactive
What happens if frequency increases without altering the physical length of aerial
The aerial becomes inductively reactive
What is the ideal VSWR ok a radio transmission line
1:1
What is audio clipping used for in voice communication
To enable consonants to be heard better
What is ils mark beacon frequency
75 Jz
What is jitter used for in a DME transmission
To make an installation recognise its own transmission
What is mode 1 & 2 of GPWS
Excessive decent rate and excessive terrain closure rate
What is needed for RHO-RHO navigation
2 DME signals
What is primary radar
Radar that sends out pulse and receives reflected pulse
What is secondary radar
Signal returned from a transponder
What is the Q code for runway heading
QFU
What is the characteristic impedance range of a parallel cable
40-150ohm
What is the difference between DME transmit and receive pulse frequency
63MHz
What is the impedance of VOR or HF aerial cables
50 ohms
What is the main cause of standing waves in wave guide
Mismatch impedance
What is the millivolt deflection per dot on ILS/VOR
75/75
What is the output of a localiser NAV receiver
Polarity sensitive DC
What is the power at pulse
Peak power
What is the power output of a DME station
1000watts
What is the reply frequency of an aircraft transponder
1090MHz
What is the time between the F2 framing pulse and the SPI
4.35us
What is the time between the framing pulses F1 and F2 in ATCRBS reply
20.3 us
What is the time taken for one radar nautical mile
12.36 us
What is the average wave length of C band radar
7cm
What is track angle
The angle measured clockwise between true north and the aircraft ground track
What is the VHF comm range at 9000 ft
110Nm
What manoeuvre does tcas 2 advise the pilot to make
RA
What modulation is used for the beams of a localiser in an ils
90 left
150 right of centre line
What must be entered in to the ins before the aircraft moves
Present position
What orbits are gps satellites in
MEO
What precautions must a pilot take when using a back course approach
Reciprocal run way heading
What type of system is an ADF
Theta
What would be the purpose of an input from an irs being connected to a weather radar
To provide stabilisation for the radar antenna
When an adf sense antenna is repositioned from the bottom of the fuselage to the top the siding of the bearing indicator must be
Reverse R1 +R2 connections only
When an aircraft is at a height of 9500ft and the QNH is 500ft what is the distance the vhf can cover
120nm
When an aircraft is flying along the extended centreline of the run way it is in the
Equi-signal sector
When an aircraft is heading due north towards a VOR station the reference and variable signals will be
180 degree out of phase
When an AM carrier is modulated it’s bandwidth
Increases
When I’m manual mode the C.D.U alert lamp of the INS will flash
Two minutes before the next way point
When painting a neoprene costed radio antenna Don not use cellulose paint
Don not use cellulose paint
When painting fibre glass radio masts with neoprene cover
Do not use cellulose paint
When performing an adf check commercial stations
Can be used in addition to ASD nav stations
When signal bandwidth increases it cause
Deterioration of pulse shape and increase in noise
When substituting rad alt cable you should consider
The speed of propagation of rad alt signal
When the ILs marker hi/lo switch is set to lo
Receiver sensitivity is reduced by 10-12dB
When the inertial platform is torqued to perform like a Schiller pendulum
The platform oscillates with respect to the local vertical
When the pilot depresses the ident button where does the ident pulse appear
4.35us after the last frame pulse
When the VOR reference and variable phases are in phase quadrature the aircraft is at the
090 radial
When using the GPS
Once the database card has expired the system will continue to operate with a warning message
When will a mode c interrogation be ignored
When the P2 pulse is higher amplitude to P1
Where does air show moving map get its position information
GPS
Where is the antenna located for watching tv
Crown skin
Which 30Hz signal from a VOR ground station is frequency modulated
The reference signal which is constant
Which colour on the wxr woukd pilots avoid turb and heavy rain
Magenta
Which frequency band is used to have line of sight comes
VHF and uhf
Which if the following frequencies is allocated to VOR
114.3MHz
Which of the following has a hyperbolic curve
Loran C
Which if the following has priority of TCAS warnings
Stall warning
Which of the following has the best frequency stability
Colpitts
Which of the following is a DME frequency
1100Mhz
Which if the following navigation system is not a hyperbolic navigation system
Doppler
Which systems provide envelope modulation information for a GPWS
Flaps/undercarriage
Which would you use to test an aircraft transponder altitude reporting system
Read the altitude directly from ATC-600 panel
Why is an aerosol tuning unit used in a HF comm system
To electrically lengthen or shorten the aerial for optimum matching of impedance
With a vertical gyro simulated to aircraft right Bank the scanner in left hand position will
Tilt down
With ADD selected the sense aerial signal is
Added to the modulated loop aerial signal
With AGC inoperative sensitivity will be affected for signals with
Both high and low signal strength
With an atc code of 0600 selected the pulses transmitted are
B2 & B4
With and increase in radar pulse duration what happens to signal to noise ratio
Decrease
With no 1 hf transmitting the interlock circuit
Does not allow hf 2 to transmit or receive
With the adf controller set to ant
Only the sense signal is used
