Radio Navigation Aids

Question 1

What info does the Doppler navigation system provide

Answer 1

Ground speed
Drift
Track

Question 2

Disadvantage of single beam Doppler system

Answer 2

Pitching errors
Vertical motion
Transmitter instability
Drift error

Question 3

What does Tacan provide

Answer 3

Slant range
Bearing to beacon
Morse cod ID for beacon

Question 4

What information does tacan provide in air to air mode

Answer 4

Coarse bearing and slant range

Question 5

Explain transponder principle

Answer 5

A/c transmits question to ground the beacon responds the time between transmission and reception determines slant range

Question 6

Tacan uses 2 modulation frequencies what are the frequencies and what do you obtain from them

Answer 6

15hz - coarse bearing
135hz - fine bearing

Question 7

What is the purpose of the identify chain

Answer 7

Provides morse code id of the beacon into the pilots headset

Question 8

What nav systems coordinate with the DME system

Answer 8

VOR
ILS
MLS

Question 9

What is the purpose of the range chain

Answer 9

Calculates the time between transition and reception determines slant range

Question 10

What information does VOR provide

Answer 10

Bearing to beacon

Fly left fly right indication

To from indication

Morse code identify

Question 11

Purpose of ILS

Answer 11

enables pilot to fly a/c along an extended runway centre line in poor visibly

Question 12

Describe LOC localiser

Answer 12

Fly left - 150hz
Fly right - 90hz

Question 13

Describe glideslope

Answer 13

Fly up -150hz
Fly down 90hz
Provides a 2 to 3• glide path angle

Question 14

Marker beacon distances

Answer 14

Outer 3.9 NM
Middle 3500ft

Question 15

Purpose of MLS

Answer 15

Elevation
Range info
Azimuth

Question 16

Advantage of MLS over ILS

Answer 16

No site prep
200 channels
Less vulnerable to signal reflections

Question 17

How does MLS determine a/c position in relation to centre line

Answer 17

Received to and fro pulse, azimuth beam sweeps the gap between pulses determines a/c position

Question 18

To and fro pulses

Answer 18

Left 14ms
Centre 10ms
Right - 6ms

(Maybe)

Question 19

What is the purpose of De-mud block

Answer 19

Separate elevation and azimuth signal

Question 20

Purpose of GPS

Answer 20

Provides continuous longitude and latitude, velocity and time anywhere on earth

Question 21

What information is contained within the signals transmitted by a gps satellite

Answer 21

Pseudo random code
Almanac data
Ephemeris data

Question 22

What info does almanac data provide

Answer 22

Status of satellites
Current time and date

Question 23

Why are atomic clocks used in gps

Answer 23

More accurate

Question 24

What factors reduce accuracy of gps

Answer 24

Satellite shading
Ionosphere and troposphere delays
Multipath errors
Orbital errors
Receiver clock errors

Question 25

Purpose of rad alt

Answer 25

Provides accurate height induction up to 5k feet

Question 26

Advantages of using rad alt over barometric

Answer 26

Extremely accurate Provides actual height above ground

Question 27

3 modes of operation (rad alt)

Answer 27

Lock/follow Search memory

Question 28

How does rad alt work (fmcw)

Answer 28

Signal is transmitted to ground reflects and comes back difference between transmitted and received frequency is proportional to height above ground

Question 29

Explain Rad alt pulsed

Answer 29

Pulse sent to ground and reflected time difference between transmitted and received pulse is directly proportional to height above ground

Question 30

How does memory mode work (rad alt)

Answer 30

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

Question 31

Purpose of GPWS

Answer 31

Provides warning to pilot of imminent collision with terrain

Question 32

Types of warnings provided by gpws

Answer 32

Visual Aural

Question 33

What systems coordinate with gpws

Answer 33

INS GPS

Question 34

What factors determine recovery manoeuvre time

Answer 34

Pilot reaction time Stick input at a preset g level Time for a/c to level

Question 35

What are secondary functions of EGPWS

Answer 35

Navigation Weapon aiming

Question 36

What is the purpose of Automatic flight control system

Answer 36

Reduce pilots workload Overcome stability problems Carry out automatic manoeuvres

Question 37

Component of auto stabilisation

Answer 37

Rate gyro Amplifier and signal processor Servo actuator Control surface Aerodynamic effects

Question 38

Purpose of autopilot

Answer 38

Reduce pilot work load Detects long term a/c instability

Question 39

Basic mode (auto pilot)

Answer 39

Holds its attitude and heading

Question 40

Autopilot modes

Answer 40

Hold or lock Acquire or capture

Question 41

Displays that indicate flight director symbology

Answer 41

Attitude indicator HSI or EHSI Multi function display Head up display

Question 42

Autopilot safety devices

Answer 42

Pilots instinctively cut out Control limiter Torque limiter Monitoring facilities Rate and angle limiters