Radio Navigation Aids Flashcards
What info does the Doppler navigation system provide
Ground speed
Drift
Track
Disadvantage of single beam Doppler system
Pitching errors
Vertical motion
Transmitter instability
Drift error
What does Tacan provide
Slant range
Bearing to beacon
Morse cod ID for beacon
What information does tacan provide in air to air mode
Coarse bearing and slant range
Explain transponder principle
A/c transmits question to ground the beacon responds the time between transmission and reception determines slant range
Tacan uses 2 modulation frequencies what are the frequencies and what do you obtain from them
15hz - coarse bearing
135hz - fine bearing
What is the purpose of the identify chain
Provides morse code id of the beacon into the pilots headset
What nav systems coordinate with the DME system
VOR
ILS
MLS
What is the purpose of the range chain
Calculates the time between transition and reception determines slant range
What information does VOR provide
Bearing to beacon
Fly left fly right indication
To from indication
Morse code identify
Purpose of ILS
enables pilot to fly a/c along an extended runway centre line in poor visibly
Describe LOC localiser
Fly left - 150hz
Fly right - 90hz
Describe glideslope
Fly up -150hz
Fly down 90hz
Provides a 2 to 3• glide path angle
Marker beacon distances
Outer 3.9 NM
Middle 3500ft
Purpose of MLS
Elevation
Range info
Azimuth
Advantage of MLS over ILS
No site prep
200 channels
Less vulnerable to signal reflections
How does MLS determine a/c position in relation to centre line
Received to and fro pulse, azimuth beam sweeps the gap between pulses determines a/c position
To and fro pulses
Left 14ms
Centre 10ms
Right - 6ms
(Maybe)
What is the purpose of De-mud block
Separate elevation and azimuth signal
Purpose of GPS
Provides continuous longitude and latitude, velocity and time anywhere on earth
What information is contained within the signals transmitted by a gps satellite
Pseudo random code
Almanac data
Ephemeris data
What info does almanac data provide
Status of satellites
Current time and date
Why are atomic clocks used in gps
More accurate
What factors reduce accuracy of gps
Satellite shading
Ionosphere and troposphere delays
Multipath errors
Orbital errors
Receiver clock errors
Purpose of rad alt
Provides accurate height induction up to 5k feet
Advantages of using rad alt over barometric
Extremely accurate
Provides actual height above ground
3 modes of operation (rad alt)
Lock/follow
Search
memory
How does rad alt work (fmcw)
Signal is transmitted to ground reflects and comes back difference between transmitted and received frequency is proportional to height above ground
Explain Rad alt pulsed
Pulse sent to ground and reflected time difference between transmitted and received pulse is directly proportional to height above ground
How does memory mode work (rad alt)
When rad alt loses lock it waits .2 seconds if signal doesn’t reappear the computer goes into search mode but pointer is held steady for 1 second
Purpose of GPWS
Provides warning to pilot of imminent collision with terrain
Types of warnings provided by gpws
Visual
Aural
What systems coordinate with gpws
INS
GPS
What factors determine recovery manoeuvre time
Pilot reaction time
Stick input at a preset g level
Time for a/c to level
What are secondary functions of EGPWS
Navigation
Weapon aiming
What is the purpose of Automatic flight control system
Reduce pilots workload
Overcome stability problems
Carry out automatic manoeuvres
Component of auto stabilisation
Rate gyro
Amplifier and signal processor
Servo actuator
Control surface
Aerodynamic effects
Purpose of autopilot
Reduce pilot work load
Detects long term a/c instability
Basic mode (auto pilot)
Holds its attitude and heading
Autopilot modes
Hold or lock
Acquire or capture
Displays that indicate flight director symbology
Attitude indicator
HSI or EHSI
Multi function display
Head up display
Autopilot safety devices
Pilots instinctively cut out
Control limiter
Torque limiter
Monitoring facilities
Rate and angle limiters
