Part 1 ILS DME Flashcards
All Marker Beacon transistors transmit on a frequency of
75 MHZ
Outer Marker is modulated by a audio tone of
400 HZ
How far is the outer marker from the runway
3-7 MILES
Middle Marker is modulated by a audio tone of
1300 HZ
How far is the middle marker from the runway
3500 feet
Outer Marker uses what light
Blue
Morse code for outer marker
dash-dash
Middle marker uses what light
Amber
Morse code for middle marker
dash-dot
Marker Beacon Antenna is located where
on the bottom of the fuselage - referred to as a boat antenna
Localizer provides guidance to the runway in what direction
lateral (left/right)
Localizer modulation
left is 90 HZ right is 150 HZ
Localizer frequency range
108.10 - 111.95 odd 1/10 MHZ example 108.10, 108.30, 108.50
Selection of a localizer frequency automatically tunes
glide slope and DME
how many V is required to deviate the needle 1 dot
75mV
how many V is required to drive the warning flag out of view
250mV
Typical glide-path angle is
3 degrees
Glideslope operates in the frequency range of
329 - 335 MHZ
Glideslope Modulation is
Above 90Hz Below 150HZ
ILS Dot represents
1.25 Total 5 degrees
Glideslope Dot represents
0.35 Total 1.4 Degrees
Signal strength will be equal when the aircraft is located on the
Glidepath
ILS
Instrument Landing System
DME
Distance Measuring Equipment
Purpose of DME
To provide distance information
How does DME work
Measures from the aircraft to a VOR or Localizer facility
What is the airborne transceiver called
interrogator
Same antenna for DME is used for
TX and RX (transmitting and receiving)
DME indication may be on
RMI, HSI or independent DME indicator
What is on the control Panel DME
Standby, Norm, Override, Test Function
what is on the indicator DME
Distance in NM, Warning/Fail Flag and Test (000.0)
DME hold
a new VOR/ILS may be selected, but the DME continues to track the previous ground station
DME frequency range is
978-1213 MHZ
DME reply pulses will be ____ MHZ higher or lower than interrogation Pulses
63 MHZ
“X” channel interrogations are how many microseconds P.R.F.
12
“Y” channel interrogations are how many microseconds
36
When the DME interrogator senses a DME station within rage, what does it transmit
interrogation Pulses (pulse pairs)
how long does the ground station hold the signals after it receives them
50 microseconds at a frequency +/- 63 MHZ
Once the DME interrogator begins to recognize its own replies what happens
enters track mode
The DME stations transmits its morse code ident tone at what frequency
What is VOR/LOC tone
1350HZ every 30 seconds
1020HZ
DME memory mode holds the last reading or velocity rate for how long
10 seconds
By measuring the distance (rho) to more than one DME station , what can be determined
position fix
Two DME readings (rho rho) provide position fix. what is 3 readings (rho-rho-rho)
required to truly remove ambiguity
