Efis Control Panel
The ADF bearing data can show on the NAV display in the VOR, APP, and MAP modes. You use the mode selector on the EFIS control panel to select the display mode for the NAV display.
The VOR/ADF switches select the VOR system or the ADF system as the source of the bearing pointer data on the NAV display. To show ADF bearing, set the VOR 1/ADF 1 switch on the EFIS control panels to the ADF 1 position.
Audio Control Panel Controls
The audio control panels (ACP) let the crew listen to ADF station audio or the morse code station identifier. You use the ACP ADF 1 receiver switch to listen to the ADF receiver audio.
Adf system – controls
The voice/range selector permits you to listen to only voice audio in the voice (V) position. The range ® position permits you to listen to the station morse code identifier. With the selector in the both (B) position, you can listen to both the voice audio and the morse code station identifier.
Navigation aid stations transmit their morse code identifier signals on a typical 1020 Hz signal. There are some ADf stations that transmit their morse code identifier on a 400 Hz signal. The voice/range selector has no effect on these stations, the station morse code identifier will always be present.
Adf system - radio magnetic indicator displays General
The radio magnetic indicator (RMI) shows bearing to a VOR or ADF station relative to the airplane magnetic heading. The RMI has two bearing pointers. The bearing pointers can show ADF or VOR data. You use the selectors on the front of the RMI to select between VOR or ADF as the source of data. The RMI has two amber flags, one for each bearing pointer. The flags come into view if the selected data source inputs fail.
General
The ADF data shows on the captain and first officer NAV displays in the VOR, APP, and MAP modes. The bearing pointers around the compass rose show VOR or ADF bearing data. To show ADF bearing, set the EFIS control panel VOR/ADF switches to ADF and set the EFIS mode selector to the VOR, APP, or MAP display modes. The bearing pointers are cyan when they show ADF data. The ADF source data and frequency or identifier shows in cyan at the bottom corners of the displays.
The bearing pointers show in the expanded and centered displays. The bearing pointers show on the expanded displays if the ADF bearing is in the compass rose display limit. This graphic shows the displays in the centered NAV display mode.
Bearing Pointers
Only bearing pointer 1 can show ADF bearing. To show ADF bearing, set the VOR/ADF 1 switch to the ADF position. When you select the ADF position, the bearing pointer shows in cyan. The DEUs remove the bearing pointer when the receiver data goes to an NCD condition, or when you set the VOR/ADF 1 switch to the off position.
ADF SYSTEM - EFIS NAV DISPLAYS
Invalid Display
The amber ADF fail flags show in the lower corners of the display when there is a failure of the ADF receivers. The ADF flags show in the same location for the expanded display.
ADF SYSTEM - FRONT PANEL BITE
Test
Push the test switch on the front of the ADF receiver to start the test. The test results show on the LED status indicators on the front of the receiver.
When you push the test switch, the receiver does a check of the internal receiver operation and the interface with the ADF control panel. The self test lasts 30 seconds. This is the test sequence that shows on the LED status indicators:
0 to 2 seconds - the LRU status and control fail LEDS come on red
2 to 4 seconds - the LRU status LED changes to green and the control fail LED remains red
4 to 12 seconds - the LRU status and control fail LEDs go off
12 to 42 seconds - the test results show on the LED status indicators.
For test results, the LRU status LED comes on green if there are no LRU faults or red if any faults occur. The control fail LED stays off if the ADF control panel input signal is valid or comes on red if there is no input from the ADF control panel or if the input signal is invalid.
Test
To see the ADF test sequence, select VOR or APP on the EFIS control panel mode selector.
A maintenance person must be in the E/E compartment to start the test from the front of the ADF receiver.
During the first two seconds of the test, the receiver output goes to a fail condition. The pointer goes out of view and the amber ADF flag shows momentarily.
For the next two seconds, the receiver output goes to an NCD condition. During this time, the amber ADF flag goes out of view and the pointer stays out of view.
Next, the test display shows and the pointer goes to a test position of 135 degrees from the heading lubber line until the end of test.
NOTE: The graphic shows a test of ADF receiver 1. For a dual system, the test is the same for ADF receiver 2.
ADF
SYSTEM - SELF-TEST