DOC AIRBUS | AMM A320FDME - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The Distance Measuring Equipment (DME) is a radio aid to medium range navigation which provides the crew with :
** ON A/C NOT FOR ALL The Distance Measuring Equipment (DME) is a radio aid to medium range navigation which provides the crew with :
- a digital readout of the slant range distance of the aircraft from a selected ground station
- audio signals which identify the selected ground station.
2. Component Location
** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C ALL | |||||
| 2SD1 | INTRG-DME, 1 | 81VU | 127 | 34-51-33 | |
| 2SD2 | INTRG-DME, 2 | 82VU | 128 | 34-51-33 | |
| 3SD1 | ANTENNA-DME, 1 | 120 | 34-51-11 | ||
| 3SD2 | ANTENNA-DME, 2 | 130 | 34-51-11 | ||
3. System Description
A. Principle
- The principle of the DME navigation is based on the measurement of the transmission time. Paired interrogation pulses go from an onboard interrogator to a selected ground station. After 50 microseconds, the station transmits the reply pulses to the aircraft.
- The measurement of time between transmitting the interrogation pulses and receiving the reply pulses is a function of the slant range distance of the aircraft to the ground station.
The measurement value is converted into nautical miles and shown to the crew. - The interrogation frequencies vary from 1041 to 1150 MHz. The reply frequencies vary from 962 to 1213 MHz.
- Furthermore, the ground station provides a Morse identification.
- The principle of the DME navigation is based on the measurement of the transmission time. Paired interrogation pulses go from an onboard interrogator to a selected ground station. After 50 microseconds, the station transmits the reply pulses to the aircraft.
- The measurement of time between transmitting the interrogation pulses and receiving the reply pulses is a function of the slant range distance of the aircraft to the ground station.
The measurement value is converted into nautical miles and shown to the crew. - The interrogation frequencies vary from 1041 to 1150 MHz. The reply frequencies vary from 962 to 1213 MHz.
- Furthermore, the ground station provides a Morse identification.
- The principle of the DME navigation is based on the measurement of the transmission time. Paired interrogation pulses go from an onboard interrogator to a selected ground station. After 50 microseconds, the station transmits the reply pulses to the aircraft.
- The measurement of time between transmitting the interrogation pulses and receiving the reply pulses is a function of the slant range distance of the aircraft to the ground station.
The measurement value is converted into nautical miles and shown to the crew. - The interrogation frequencies vary from 1041 to 1150 MHz. The reply frequencies vary from 962 to 1213 MHz.
- Furthermore, the ground station provides a Morse identification.
- The principle of the DME navigation is based on the measurement of the transmission time. Paired interrogation pulses go from an onboard interrogator to a selected ground station. After 50 microseconds, the station transmits the reply pulses to the aircraft.
- The measurement of time between transmitting the interrogation pulses and receiving the reply pulses is a function of the slant range distance of the aircraft to the ground station.
The measurement value is converted into nautical miles and shown to the crew. - The interrogation frequencies vary from 1025 to 1150 MHz. The reply frequencies vary from 962 to 1213 MHz.
- Furthermore, the ground station provides a Morse identification.
B. System Architecture
The DME comprises two independent systems. Each system consists of :
DME - Control and Indicating ** ON A/C NOT FOR ALL
DME - Control and Indicating ** ON A/C NOT FOR ALL
DME - Control and Indicating ** ON A/C NOT FOR ALL
DME - Control and Indicating ** ON A/C NOT FOR ALL
DME - Control and Indicating ** ON A/C NOT FOR ALL
The DME comprises two independent systems. Each system consists of :
- one DME interrogator 2SD1 (2SD2)
- one DME antenna 3SD1 (3SD2)
- one dual VOR/ADF/DME Radio Magnetic Indicator (VOR/ADF/DME RMI) 21FN.
- the CAPT (F/O) Audio Control Panel (ACP) 2RN1 (2RN2) and the Audio Management Unit (AMU) 1RN for audio controls
- the Multipurpose Control and Display Unit 1(2) (MCDU) 3CA1 (3CA2), the Radio Management Panel 1(2) (RMP) 1RG1 (1RG2), and the Flight Management and Guidance Computer 1(2) (FMGC) 1CA1 (1CA2) for frequency/course selection
- the MCDU and the Centralized Fault-Display Interface-Unit (CFDIU) 1TW for test causes.
- the CAPT and F/O Primary Flight Displays (PFD)
- the CAPT and F/O Navigation Displays (ND)
- the VOR/ADF/DME RMI
- the MCDU(s) (maintenance data).
- one DME interrogator 2SD1 (2SD2)
- one DME antenna 3SD1 (3SD2)
- one dual VOR/ADF/DME Radio Magnetic Indicator (VOR/ADF/DME RMI) 21FN.
DME - Control and Indicating ** ON A/C NOT FOR ALL DME - Control and Indicating ** ON A/C NOT FOR ALL - the CAPT (F/O) Audio Control Panel (ACP) 2RN1 (2RN2) and the Audio Management Unit (AMU) 1RN for audio controls
- the Multipurpose Control and Display Unit 1(2) (MCDU) 3CA1 (3CA2), the Radio Management Panel 1(2) (RMP) 1RG1 (1RG2), and the Flight Management and Guidance Computer 1(2) (FMGC) 1CA1 (1CA2) for frequency/course selection
- the MCDU and the Centralized Fault-Display Interface-Unit (CFDIU) 1TW for test causes.
- the CAPT and F/O Primary Flight Displays (PFD)
- the CAPT and F/O Navigation Displays (ND)
- the VOR/ADF/DME RMI
- the MCDU(s) (maintenance data).
- one DME interrogator 2SD1 (2SD2)
- one DME antenna 3SD1 (3SD2)
DME - Control and Indicating ** ON A/C NOT FOR ALL DME - Control and Indicating ** ON A/C NOT FOR ALL DME - Control and Indicating ** ON A/C NOT FOR ALL - the CAPT (F/O) Audio Control Panel (ACP) 2RN1 (2RN2) and the Audio Management Unit (AMU) 1RN for audio controls
- the Multipurpose Control and Display Unit 1(2) (MCDU) 3CA1 (3CA2), the Radio Management Panel 1(2) (RMP) 1RG1 (1RG2), and the Flight Management and Guidance Computer 1(2) (FMGC) 1CA1 (1CA2) for frequency/course selection
- The MCDU and the Centralized Fault-Display Interface-Unit (CFDIU) 1TW for test causes.
- the CAPT and F/O Primary Flight Displays (PFD)
- the CAPT and F/O Navigation Displays (ND)
- the MCDU(s) (maintenance data).
- one DME interrogator 2SD1 (2SD2),
- one DME antenna 3SD1 (3SD2),
- one dual VOR/ADF/DME Radio Magnetic Indicator (VOR/ADF/DME RMI) 21FN.
- the CAPT (F/O) Audio Control Panel (ACP) 2RN1 (2RN2) and the Audio Management Unit (AMU) 1RN for audio controls,
- the Multipurpose Control and Display Unit 1(2) (MCDU) 3CA1 (3CA2), the Radio Management Panel 1(2) (RMP) 1RG1 (1RG2), and the Flight Management and Guidance Computer 1(2) (FMGC) 1CA1 (1CA2) for frequency/course selection,
- the MCDU and the Centralized Fault Display Interface Unit (CFDIU) 1TW for test causes.
- the CAPT and F/O Primary Flight Displays (PFD),
- the CAPT and F/O Navigation Displays (ND),
- the VOR/ADF/DME RMI,
- the MCDU(s) (maintenance data).
C. Utilization Technical Data
(a) On the PFDs
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
(b) On the NDs
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when :
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions:
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when :
- you set the mode selector switch on the EFIS control section of the FCU to ROSE (ILS, VOR, NAV) or ARC
- you set the ADF/VOR/OFF switch to VOR.
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions:
- a circle for the DME station
- circle plus cross symbol for the VOR/DME station.
(c) On the VOR/ADF/DME RMI
Two windows are available for indication of both distances from the DME 1 and DME 2 (Item 4) when the VOR/DME stations are collocated.
When the DME or RMI monitoring circuits detect a fault, the corresponding display window (Item 5) is blanked.
In case of Non Computed Data (NCD) (out-of-range station) the windows show white horizontal dashed lines (Item 6).
In addition, the LEDs on the face of the DME interrogator indicate the status of the DME system.
Two windows are available for indication of both distances from the DME 1 and DME 2 (Item 4) when the VOR/DME stations are collocated.
When the DME or RMI monitoring circuits detect a fault, the corresponding display window (Item 5) is blanked.
In case of Non Computed Data (NCD) (out-of-range station) the windows show white horizontal dashed lines (Item 6).
In addition, the LEDs on the face of the DME interrogator indicate the status of the DME system.
(2) Audio control
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loud speakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the VOR pushbutton switch on the ACP.
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loud speakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the VOR pushbutton switch on the ACP.
(3) Data display
DME - Data and Fault Displays ** ON A/C NOT FOR ALL
DME - Data and Fault Displays ** ON A/C NOT FOR ALL
DME - Data and Fault Displays ** ON A/C NOT FOR ALL DME - Data and Fault Displays ** ON A/C NOT FOR ALL (a) On the PFDs
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
(b) On the NDs
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when :
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions:
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when :
- you set the mode selector switch on the EFIS control section of the FCU to ROSE (ILS, VOR, NAV) or ARC
- you set the ADF/VOR/OFF switch to VOR.
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions:
- a circle for the DME station
- circle plus cross symbol for the VOR/DME station.
(c) On the VOR/ADF/DME RMI
Two windows are available for indication of both distances from the DME 1 and DME 2 (Item 4) when the VOR/DME stations are collocated.
When the DME or RMI monitoring circuits detect a fault, the corresponding display window (Item 5) is blanked.
In case of Non Computed Data (NCD) (out-of-range station) the windows show white horizontal dashed lines (Item 6).
In addition, the LEDs on the face of the DME interrogator indicate the status of the DME system.
Two windows are available for indication of both distances from the DME 1 and DME 2 (Item 4) when the VOR/DME stations are collocated.
When the DME or RMI monitoring circuits detect a fault, the corresponding display window (Item 5) is blanked.
In case of Non Computed Data (NCD) (out-of-range station) the windows show white horizontal dashed lines (Item 6).
In addition, the LEDs on the face of the DME interrogator indicate the status of the DME system.
(4) Audio control
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loud speakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the ILS pushbutton switch on the ACP.
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loud speakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the ILS pushbutton switch on the ACP.
(a) On the PFDs
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
(b) On the NDs
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when :
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions :
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when :
- you set the mode selector switch on the EFIS control section of the FCU to ROSE (ILS, VOR, NAV) or ARC
- you set the ADF/VOR/OFF switch to VOR.
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions :
- a circle for the DME station
- circle plus cross symbol for the VOR/DME station.
(c) In addition, the LEDs on the face of the DME interrogator indicate the status of the DME system.
(6) Audio control
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loud speakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the ILS pushbutton switch on the ACP.
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loud speakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the ILS pushbutton switch on the ACP.
(a) On the PFDs
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
With ILS/DME collocated stations, the ILS/DME distance is shown in magenta in the L lower corner of the PFD (Item 1). These data come into view when you push the ILS pushbutton switch located on the EFIS control section of the Flight Control Unit (FCU).
(b) On the NDs
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when:
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions:
The VOR/DME distance is shown in green in the L lower corner of the ND for DME system 1 (Item 2), and in the R lower corner of the ND for DME system 2 (Item 3) when:
- you set the mode selector switch on the EFIS control section of the FCU to ROSE (ILS, VOR, NAV) or ARC,
- you set the ADF/VOR/OFF switch to VOR.
Display of the VOR/DME and DME ground stations which are not already included in the flight plan, with the mode selector switch in ROSE NAV and ARC positions:
- a circle for the DME station
- circle plus cross symbol for the VOR/DME station.
(c) On the VOR/ADF/DME RMI
Two windows are available for indication of both distances from the DME 1 and DME 2 (Item 4) when the VOR/DME stations are collocated.
When the DME or RMI monitoring circuits detect a fault, the corresponding display window (Item 5) is blanked.
In case of Non Computed Data (NCD) (out-of-range station) the windows show white horizontal dashed lines (Item 6).
In addition, the LEDs on the face of the DME interrogator indicate the status of the DME system.
Two windows are available for indication of both distances from the DME 1 and DME 2 (Item 4) when the VOR/DME stations are collocated.
When the DME or RMI monitoring circuits detect a fault, the corresponding display window (Item 5) is blanked.
In case of Non Computed Data (NCD) (out-of-range station) the windows show white horizontal dashed lines (Item 6).
In addition, the LEDs on the face of the DME interrogator indicate the status of the DME system.
(8) Audio control
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loudspeakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the ILS pushbutton switch on the ACP.
The DME interrogator applies its audio output to the audio integrating system. This system controls and directs the output to the headsets and/or the loudspeakers. The pilot can control the DME audio signals by pressing the VOR pushbutton switch on the ACP and adjusting the related potentiometer to the correct audio level.
In case of collocated ILS/DME ground stations and when the ILS pushbutton switch is pressed on the EFIS control section of the FCU, the pilot can control the DME audio signal through the ILS pushbutton switch on the ACP.
4. Power Supply
Energization of each system is through 115VAC 400 Hz buses :
Energization of each system is through 115VAC 400 Hz buses :
** ON A/C NOT FOR ALL Energization of each system is through 115VAC 400 Hz buses :
- 115VAC SHED ESS BUS 801XP via circuit breaker 1SD1 for system 1
- 115VAC BUS2 BUS 204XP via circuit breaker 1SD2 for system 2.
Energization of each system is through 115VAC 400 Hz buses :
- 115VAC SHED ESS BUS 801XP via circuit breaker 1SD1 for system 1
- 115VAC BUS2 BUS 204XP via circuit breaker 1SD2 for system 2.
5. Component Description
A. DME Interrogator FIN: 2-SD-1 FIN: 2-SD-2
(1) Description
The face of the interrogator is fitted with a handle, two lugs, a TEST pushbutton switch and two LEDs.
The name, color and function of the two LEDs are as follows:
The face of the interrogator is fitted with a handle, two lugs, a TEST pushbutton switch and two LEDs.
The name, color and function of the two LEDs are as follows:
- CONTROL FAIL (red) indicates invalid frequency input tuning words
- LRU STATUS (green) indicates that no faults are detected during the test sequence
- LRU STATUS (red) indicates that a fault is detected during the test sequence.
- Top Plug (TP): connection with the automatic test circuit
- Middle Plug (MP): connection with the antenna and peripheral circuits
- Bottom Plug (BP): connection with the power supply circuit and suppressor.
(2) Description
The back is equipped with one ARINC 600 size one connector, which includes three plugs:
The back is equipped with one ARINC 600 size one connector, which includes three plugs:
- Top Plug (TP): is not installed
- Middle Plug (MP): aircraft interconnection, and connection to the coaxial antenna
- Bottom Plug (BP): connection with the power supply circuit and suppressor.
The face of the interrogator is fitted with a handle, two attaching parts, a TEST pushbutton switch and three LEDs.
The names, colors and functions of the three LEDs are as follows:
(a) DME STATUS:
- amber: indicates that the test is in progress
- green: indicates that no faults are detected during the self-test sequence.
- red: indicates that a fault is detected during the self-test sequence.
(b) CONTROL FAULT:
- amber: indicates that the test is in progress
- red: indicates invalid frequency input tuning words or no transmission
- off: indicates that no faults are detected during the self-test sequence.
(c) ANTENNA FAULT:
- amber: indicates that the test is in progress
- red: indicates a failure of the antenna (discontinuity)
- off: indicates that no faults are detected during the self-test sequence.
(a) Interrogation
When the frequency for a DME ground station is selected on the RMP or by the FMGC, a serial digital tuning word is transmitted along an ARINC 429 data bus to the range processor in the interrogator. The range processor uses the frequency data to provide a tuning word for the synthesizer. In the synthesizer the Voltage Controlled Oscillator (VCO), which operates in the L-band range of 1025 to 1150 MHz, generates the transmitter signal which after amplification is applied to the driver.
The transmitter part of the interrogator consists of a VCO with a quartz-stabilized, phase-locked-loop frequency synthesizer and a power amplifier. The synthesizer is controlled by the 8OC/86 CPU. The power amplifier is energized only during the pulse transmission and the transmitted energy goes to the antenna through a circulator. The receiver part consists of a preselecting filter, an RF amplifier, a mixer and an IF amplifier centered on 63 MHz. The IF amplifier output pulses are then detected.
When the frequency for a DME ground station is selected on the RMP or by the FMGC, a serial digital tuning word is transmitted along an ARINC 429 data bus to the range processor in the interrogator. The range processor uses the frequency data to provide a tuning word for the synthesizer. In the synthesizer the Voltage Controlled Oscillator (VCO), which operates in the L-band range of 1025 to 1150 MHz, generates the transmitter signal which after amplification is applied to the driver.
The transmitter part of the interrogator consists of a VCO with a quartz-stabilized, phase-locked-loop frequency synthesizer and a power amplifier. The synthesizer is controlled by the 8OC/86 CPU. The power amplifier is energized only during the pulse transmission and the transmitted energy goes to the antenna through a circulator. The receiver part consists of a preselecting filter, an RF amplifier, a mixer and an IF amplifier centered on 63 MHz. The IF amplifier output pulses are then detected.
(b) Reply signal processing
Reply pulses from a DME ground station are received by the antenna and applied through the circulator to the receiver.
In the receiver the reply pulses are filtered, amplified and mixed with the local oscillation from the driver to produce a 63 MHz IF signal. After further amplification and filtering, a second mixer combines the 63 MHz signal with a local 52.3 MHz oscillation to produce a 10.7 MHz IF signal which is applied to the video processor through a video detector.
In the video processor the signal is applied to a threshold detector and a pulse pair decoder. The threshold detector determines the range measurement timing. The video processor verifies that a valid pulse is received and applies the valid video pulse to the range processor module. An audio identification algorithm executed by the processor board decodes and synthesizes a 1350 Hz audio signal which reproduces the source identification signal transmitted by the DME ground station and provides an output to the audio integrating system in the aircraft.
Reply pulses from a DME ground station are received by the antenna and applied through the circulator to the receiver.
In the receiver the reply pulses are filtered, amplified and mixed with the local oscillation from the driver to produce a 63 MHz IF signal. After further amplification and filtering, a second mixer combines the 63 MHz signal with a local 52.3 MHz oscillation to produce a 10.7 MHz IF signal which is applied to the video processor through a video detector.
In the video processor the signal is applied to a threshold detector and a pulse pair decoder. The threshold detector determines the range measurement timing. The video processor verifies that a valid pulse is received and applies the valid video pulse to the range processor module. An audio identification algorithm executed by the processor board decodes and synthesizes a 1350 Hz audio signal which reproduces the source identification signal transmitted by the DME ground station and provides an output to the audio integrating system in the aircraft.
(c) Distance measurement
A range counter in the range processor module, which generates the driver and power amplifier trigger pulses, measures the time interval between the first interrogation pulse and the reception of the first valid video pulse. The time delay of the reply pulse is converted to a distance value and stored in memory. During an interrogation cycle, additional reply pulse delay measurements are made and processed to produce an accurate range distance.
The range distance data is transmitted through ARINC 429 data ports to the DMC, the RMI and the FMGC.
A range counter in the range processor module, which generates the driver and power amplifier trigger pulses, measures the time interval between the first interrogation pulse and the reception of the first valid video pulse. The time delay of the reply pulse is converted to a distance value and stored in memory. During an interrogation cycle, additional reply pulse delay measurements are made and processed to produce an accurate range distance.
The range distance data is transmitted through ARINC 429 data ports to the DMC, the RMI and the FMGC.
(d) Suppression
A suppression coaxial connects all these units: the DME interrogators and ATC/ TCAS system. This prevents transmission from one system while the other is in reception mode. This is necessary because all these systems operate on the same frequency range.
A suppression coaxial connects all these units: the DME interrogators and ATC/ TCAS system. This prevents transmission from one system while the other is in reception mode. This is necessary because all these systems operate on the same frequency range.
(e) Modes
The DME system has three basic modes : standby, directed and free scan.
The DME system has three basic modes : standby, directed and free scan.
- Standby mode: in this mode no distance data is computed, the NCD indication appears in the RMI, and the NCD signal is also transmitted to the FMGC. The DME reverts to the standby mode when it is not communicating with a ground station.
- Directed mode: in this mode up to five foreground stations are designated by the FMGC to the DME interrogator.
- Free scanning mode: in this mode any or all of five stations can be designated by the FMGC. If less than five stations are designated, the DME fills the empty slots with the closest stations.
The DME scans the background loop, consisting of the other 247 stations, searching for station pulses.
(4) Manual self-test and automatic monitoring
(a) Purpose
The fault monitor of the DME interrogator periodically checks the circuits and operation of the interrogator while the unit is installed in the aircraft. The fault monitor uses Built-In Test Equipment (BITE) to gather operating parameters relating to the fault and stores historical fault data relating to the failure in the maintenance fault memory. If a failure is detected, the crew and/or the FMCS is alerted that the unit does not operate correctly. The stored fault data can be used by the shop technician as an aid in trouble shooting the faulty LRU.
The fault monitor of the DME interrogator periodically checks the circuits and operation of the interrogator while the unit is installed in the aircraft. The fault monitor uses Built-In Test Equipment (BITE) to gather operating parameters relating to the fault and stores historical fault data relating to the failure in the maintenance fault memory. If a failure is detected, the crew and/or the FMCS is alerted that the unit does not operate correctly. The stored fault data can be used by the shop technician as an aid in trouble shooting the faulty LRU.
(b) Operation
The fault monitor self-test periodically interrupts normal DME operation and uses BITE to monitor a number of parameters selected to determine the status of functionally replaceable modules. Under normal conditions, the self-test is performed every 60 s. If a failure is detected, the self-test is performed every 5 s.
Safety related failures detected while the aircraft is in the air cause DME service to be denied to the crew and/or the FMCS. A detected failure causes the DME to output ARINC data words containing failure and No Computed Data indications. Safety related failures include wrong distance, wrong channel, etc. If the failure is not safety related (low RF power, poor receiver sensitivity, etc.), the DME continues to attempt to operate normally until the aircraft is on the ground.
If any failure is detected while the aircraft is on the ground, DME service is denied to the crew and/or the FMCS. The DME outputs ARINC data words containing failure and No Computed Data indications.
Data relating to any failure detected when the aircraft is in the air is stored in Non-Volatile Memory on processor card A7. The Non-Volatile Memory can be accessed by the shop technician as an aid to fault isolation.
The DME self-test procedure can be manually initiated by either the ARINC 429 input control word or the DME functional test rear connector discrete. When the self-test procedure is initiated in one of these ways, the ARINC output data words indicate a failure for 2 seconds, No Computed Data for 2 seconds, and then a continuous self-test indication. The DME stays in self-test until released.
While the self-test procedure is being performed, the DME continues to calculate distance, except when the fault monitor test is initiated.
The fault monitor self-test periodically interrupts normal DME operation and uses BITE to monitor a number of parameters selected to determine the status of functionally replaceable modules. Under normal conditions, the self-test is performed every 60 s. If a failure is detected, the self-test is performed every 5 s.
Safety related failures detected while the aircraft is in the air cause DME service to be denied to the crew and/or the FMCS. A detected failure causes the DME to output ARINC data words containing failure and No Computed Data indications. Safety related failures include wrong distance, wrong channel, etc. If the failure is not safety related (low RF power, poor receiver sensitivity, etc.), the DME continues to attempt to operate normally until the aircraft is on the ground.
If any failure is detected while the aircraft is on the ground, DME service is denied to the crew and/or the FMCS. The DME outputs ARINC data words containing failure and No Computed Data indications.
Data relating to any failure detected when the aircraft is in the air is stored in Non-Volatile Memory on processor card A7. The Non-Volatile Memory can be accessed by the shop technician as an aid to fault isolation.
The DME self-test procedure can be manually initiated by either the ARINC 429 input control word or the DME functional test rear connector discrete. When the self-test procedure is initiated in one of these ways, the ARINC output data words indicate a failure for 2 seconds, No Computed Data for 2 seconds, and then a continuous self-test indication. The DME stays in self-test until released.
While the self-test procedure is being performed, the DME continues to calculate distance, except when the fault monitor test is initiated.
(a) Interrogation
When the frequency for a DME ground station is selected on the RMP or by the FMGC, a serial digital tuning word is transmitted along an ARINC 429 data bus to the range processor in the interrogator. The range processor uses the frequency data to provide a tuning word for the synthesizer. In the synthesizer the Voltage Controlled Oscillator (VCO), which operates in the L-band range of 1025 to 1150 MHz, generates the transmitter signal which after amplification is applied to the driver.
The transmitter part of the interrogator consists of a VCO with a quartz-stabilized, phase-locked-loop frequency synthesizer and a power amplifier. The synthesizer is controlled by the 8OC/86 CPU. The power amplifier is energized only during the pulse transmission and the transmitted energy goes to the antenna through a circulator. The receiver part consists of a preselecting filter, an RF amplifier, a mixer and an IF amplifier centered on 63 MHz. The IF amplifier output pulses are then detected.
When the frequency for a DME ground station is selected on the RMP or by the FMGC, a serial digital tuning word is transmitted along an ARINC 429 data bus to the range processor in the interrogator. The range processor uses the frequency data to provide a tuning word for the synthesizer. In the synthesizer the Voltage Controlled Oscillator (VCO), which operates in the L-band range of 1025 to 1150 MHz, generates the transmitter signal which after amplification is applied to the driver.
The transmitter part of the interrogator consists of a VCO with a quartz-stabilized, phase-locked-loop frequency synthesizer and a power amplifier. The synthesizer is controlled by the 8OC/86 CPU. The power amplifier is energized only during the pulse transmission and the transmitted energy goes to the antenna through a circulator. The receiver part consists of a preselecting filter, an RF amplifier, a mixer and an IF amplifier centered on 63 MHz. The IF amplifier output pulses are then detected.
(b) Reply signal processing
Reply pulses from a DME ground station are received by the antenna and applied through the circulator to the receiver.
In the receiver the reply pulses are filtered, amplified and mixed with the local oscillation from the driver to produce a 63 MHz IF signal. After further amplification and filtering, a second mixer combines the 63 MHz signal with a local 52.3 MHz oscillation to produce a 10.7 MHz IF signal which is applied to the video processor through a video detector.
In the video processor the signal is applied to a threshold detector and a pulse pair decoder. The threshold detector determines the range measurement timing. The video processor verifies that a valid pulse is received and applies the valid video pulse to the range processor module. An audio identification algorithm executed by the processor board decodes and synthesizes a 1350 Hz audio signal which reproduces the source identification signal transmitted by the DME ground station and provides an output to the audio integrating system in the aircraft.
Reply pulses from a DME ground station are received by the antenna and applied through the circulator to the receiver.
In the receiver the reply pulses are filtered, amplified and mixed with the local oscillation from the driver to produce a 63 MHz IF signal. After further amplification and filtering, a second mixer combines the 63 MHz signal with a local 52.3 MHz oscillation to produce a 10.7 MHz IF signal which is applied to the video processor through a video detector.
In the video processor the signal is applied to a threshold detector and a pulse pair decoder. The threshold detector determines the range measurement timing. The video processor verifies that a valid pulse is received and applies the valid video pulse to the range processor module. An audio identification algorithm executed by the processor board decodes and synthesizes a 1350 Hz audio signal which reproduces the source identification signal transmitted by the DME ground station and provides an output to the audio integrating system in the aircraft.
(c) Distance measurement
A range counter in the range processor module, which generates the driver and power amplifier trigger pulses, measures the time interval between the first interrogation pulse and the reception of the first valid video pulse. The time delay of the reply pulse is converted to a distance value and stored in memory. During an interrogation cycle, additional reply pulse delay measurements are made and processed to produce an accurate range distance.
The range distance data is transmitted through ARINC 429 data ports to the DMC and the FMGC.
A range counter in the range processor module, which generates the driver and power amplifier trigger pulses, measures the time interval between the first interrogation pulse and the reception of the first valid video pulse. The time delay of the reply pulse is converted to a distance value and stored in memory. During an interrogation cycle, additional reply pulse delay measurements are made and processed to produce an accurate range distance.
The range distance data is transmitted through ARINC 429 data ports to the DMC and the FMGC.
(d) Suppression
A suppression coaxial connects all these units: the DME interrogators and ATC/ TCAS system. This prevents transmission from one system while the other is in reception mode. This is necessary because all these systems operate on the same frequency range.
A suppression coaxial connects all these units: the DME interrogators and ATC/ TCAS system. This prevents transmission from one system while the other is in reception mode. This is necessary because all these systems operate on the same frequency range.
(e) Modes
The DME system has three basic modes : standby, directed and free scan.
The DME system has three basic modes : standby, directed and free scan.
- Standby mode: in this mode no distance data is computed, and the NCD signal is also transmitted to the FMGC. The DME reverts to the standby mode when it is not communicating with a ground station.
- Directed mode: in this mode up to five foreground stations are designated by the FMGC to the DME interrogator.
- Free scanning mode: in this mode any or all of five stations can be designated by the FMGC. If less than five stations are designated, the DME fills the empty slots with the closest stations.
The DME scans the background loop, consisting of the other 247 stations, searching for station pulses.
(6) Manual self-test and automatic monitoring
(a) Purpose
The fault monitor of the DME interrogator periodically checks the circuits and operation of the interrogator while the unit is installed in the aircraft. The fault monitor uses Built-In Test Equipment (BITE) to gather operating parameters relating to the fault and stores historical fault data relating to the failure in the maintenance fault memory. If a failure is detected, the crew and/or the FMCS is alerted that the unit does not operate correctly. The stored fault data can be used by the shop technician as an aid in trouble shooting the faulty LRU.
The fault monitor of the DME interrogator periodically checks the circuits and operation of the interrogator while the unit is installed in the aircraft. The fault monitor uses Built-In Test Equipment (BITE) to gather operating parameters relating to the fault and stores historical fault data relating to the failure in the maintenance fault memory. If a failure is detected, the crew and/or the FMCS is alerted that the unit does not operate correctly. The stored fault data can be used by the shop technician as an aid in trouble shooting the faulty LRU.
(b) Operation
The fault monitor self-test periodically interrupts normal DME operation and uses BITE to monitor a number of parameters selected to determine the status of functionally replaceable modules. Under normal conditions, the self-test is performed every 60 s. If a failure is detected, the self-test is performed every 5 s.
Safety related failures detected while the aircraft is in the air cause DME service to be denied to the crew and/or the FMCS. A detected failure causes the DME to output ARINC data words containing failure and No Computed Data indications. Safety related failures include wrong distance, wrong channel, etc. If the failure is not safety related (low RF power, poor receiver sensitivity, etc.), the DME continues to attempt to operate normally until the aircraft is on the ground.
If any failure is detected while the aircraft is on the ground, DME service is denied to the crew and/or the FMCS. The DME outputs ARINC data words containing failure and No Computed Data indications.
Data relating to any failure detected when the aircraft is in the air is stored in Non-Volatile Memory on processor card A7. The Non-Volatile Memory can be accessed by the shop technician as an aid to fault isolation.
The DME self-test procedure can be manually initiated by either the ARINC 429 input control word or the DME functional test rear connector discrete. When the self-test procedure is initiated in one of these ways, the ARINC output data words indicate a failure for 2 seconds, No Computed Data for 2 seconds, and then a continuous self-test indication. The DME stays in self-test until released.
While the self-test procedure is being performed, the DME continues to calculate distance, except when the fault monitor test is initiated.
The fault monitor self-test periodically interrupts normal DME operation and uses BITE to monitor a number of parameters selected to determine the status of functionally replaceable modules. Under normal conditions, the self-test is performed every 60 s. If a failure is detected, the self-test is performed every 5 s.
Safety related failures detected while the aircraft is in the air cause DME service to be denied to the crew and/or the FMCS. A detected failure causes the DME to output ARINC data words containing failure and No Computed Data indications. Safety related failures include wrong distance, wrong channel, etc. If the failure is not safety related (low RF power, poor receiver sensitivity, etc.), the DME continues to attempt to operate normally until the aircraft is on the ground.
If any failure is detected while the aircraft is on the ground, DME service is denied to the crew and/or the FMCS. The DME outputs ARINC data words containing failure and No Computed Data indications.
Data relating to any failure detected when the aircraft is in the air is stored in Non-Volatile Memory on processor card A7. The Non-Volatile Memory can be accessed by the shop technician as an aid to fault isolation.
The DME self-test procedure can be manually initiated by either the ARINC 429 input control word or the DME functional test rear connector discrete. When the self-test procedure is initiated in one of these ways, the ARINC output data words indicate a failure for 2 seconds, No Computed Data for 2 seconds, and then a continuous self-test indication. The DME stays in self-test until released.
While the self-test procedure is being performed, the DME continues to calculate distance, except when the fault monitor test is initiated.
(7) Internal description
The DME interrogator includes:
The DME interrogator includes:
- an RF module,
- a synthesizer/modulator assembly,
- a main processor (CPU and I/O) assembly,
- a video processor,
- a power supply assembly,
- a rear interconnect module,
- a memory card interface module.
(a) RF module
This module consists of a single Personal Computer (PC) board that is mounted in a closed aluminum chassis. It contains:
This module consists of a single Personal Computer (PC) board that is mounted in a closed aluminum chassis. It contains:
- a transmitter,
- a receiver,
- a circulator,
- a low-pass filter.
1 Transmitter
The solid-state transmitter contains a six-stage amplifier followed by a 700W (typical) final amplifier. The pulse modulation is applied to the first six stages of amplification. It is tuned to frequencies in the 1025-1150 MHz range.
The solid-state transmitter contains a six-stage amplifier followed by a 700W (typical) final amplifier. The pulse modulation is applied to the first six stages of amplification. It is tuned to frequencies in the 1025-1150 MHz range.
2 Receiver
The single-conversion superheterodyne receiver consists of a varactor tuned preselector, 1 GHz preamplifier, mixer, band-pass filters, and a 63 MHz logarithmic IF amplifier. The preselector is tuned to frequencies in the 962-1213 MHz range.
The single-conversion superheterodyne receiver consists of a varactor tuned preselector, 1 GHz preamplifier, mixer, band-pass filters, and a 63 MHz logarithmic IF amplifier. The preselector is tuned to frequencies in the 962-1213 MHz range.
3 Circulator
The circulator routes the transmitter output to the antenna and the antenna received signal to the receiver. It provides isolation to protect the transmitter output amplifier devices from reflected signals.
The circulator routes the transmitter output to the antenna and the antenna received signal to the receiver. It provides isolation to protect the transmitter output amplifier devices from reflected signals.
4 Low-pass filter
The low-pass filter prevents internal transmitter harmonics from being passed to the antenna.
The low-pass filter prevents internal transmitter harmonics from being passed to the antenna.
(b) Synthetizer/Modulator Assembly
This module contains the digital frequency synthesizer and transmitter modulator circuits.
The digital frequency synthesizer supplies a signal used both as the local oscillator input to the receiver mixer and as the low-level CW signal the transmitter. This circuit consists of a phase-locked loop and Voltage Control Oscillator (VCO) which is tuned to the desired channel frequency by a serial tuning word supplied by the video processor module.
The modulator supplies the on/off signal that corresponds to the X or Y pulse pairs associated with the channel frequency. An interrogation is transmitted by triggering the series of on/off modulation to control the transmitter amplifier stages that drive the final amplifier.
This module contains the digital frequency synthesizer and transmitter modulator circuits.
The digital frequency synthesizer supplies a signal used both as the local oscillator input to the receiver mixer and as the low-level CW signal the transmitter. This circuit consists of a phase-locked loop and Voltage Control Oscillator (VCO) which is tuned to the desired channel frequency by a serial tuning word supplied by the video processor module.
The modulator supplies the on/off signal that corresponds to the X or Y pulse pairs associated with the channel frequency. An interrogation is transmitted by triggering the series of on/off modulation to control the transmitter amplifier stages that drive the final amplifier.
(c) Main Processor (CPU and I/O) Assembly
This module contains the CPU that executes the signal processing using a microprocessor.
It also contains the I/O section consisting of ARINC 429 transmitters and receivers, and discrete I/O logic to provide the interfaces with other aircraft systems including the Centralized Fault Display System (CFDS) and displays.
ARINC 429 inputs and outputs are processed by a specially designed ARINC 429 LSI transceiver device. External level converters are used to satisfy the ARINC 429 characteristics for the transmitters and convert input ARINC 429 signals to logic levels.
All discrete inputs and outputs external to the DME are processed by discrete components to provide level shifting and latching.
The following types of devices are employed:
This module contains the CPU that executes the signal processing using a microprocessor.
It also contains the I/O section consisting of ARINC 429 transmitters and receivers, and discrete I/O logic to provide the interfaces with other aircraft systems including the Centralized Fault Display System (CFDS) and displays.
ARINC 429 inputs and outputs are processed by a specially designed ARINC 429 LSI transceiver device. External level converters are used to satisfy the ARINC 429 characteristics for the transmitters and convert input ARINC 429 signals to logic levels.
All discrete inputs and outputs external to the DME are processed by discrete components to provide level shifting and latching.
The following types of devices are employed:
- digital-to-analog converter devices to generate control and test signals,
- Field Programmable Logic Array (FPLA) devices to accept, decode and generate discrete signals,
- memory devices (bootstrap, program, nonvolatile, and data),
- data recorder interface,
- front panel display driver,
- RS-232 interface,
- clock generators.
(d) Video Processor
This module contains a Field Programmable Gate Array (FPGA) which is the control center for the video processor. The video processor provides the following operations:
This module contains a Field Programmable Gate Array (FPGA) which is the control center for the video processor. The video processor provides the following operations:
- converts tuning commands from CPU to serial data to tune the transmit/receive frequency synthesizer,
- generates the corresponding receiver preselector tuning voltage,
- generates the corresponding X or Y pulse modulation for the interrogation,
- generates the output mutual suppression pulse for an interrogation,
- detects the input mutual suppression pulse and inhibits reception and video processing,
- determines the logarithmic IF noise threshold setting,
- starts the range (distance) counter when an interrogation is transmitted,
- digitizes the video signals from the receiver logarithmic IF amplifier,
- validates the amplitude, spacing, and width of the digitized video pulse pairs,
- stores the range counter value in a FIFO when each valid pulse pair is decoded,
- analog-to-digital converter devices to process the received signals and BITE test point voltages,
- generates the audio tone for the Morse code station identity aural output,
- provides for integrity testing.
(e) Power Supply Assembly
This module is a self contained, high efficiency power supply that converts the 115 VAC, 400 Hz AC power into the required DC operating voltages (+70V, +24V, +12V, -12V and +5V).
It includes an EMI filter to reduce electromagnetic interference from being radiated from the power lines.
This module is a self contained, high efficiency power supply that converts the 115 VAC, 400 Hz AC power into the required DC operating voltages (+70V, +24V, +12V, -12V and +5V).
It includes an EMI filter to reduce electromagnetic interference from being radiated from the power lines.
(f) Rear Interconnect Module
The rear connector assembly provides the interwiring from the aircraft interface to the internal modules. A combination of series resistors, series of transient voltage suppressors, and ferrite pin filters provide High Intensity Radiation Fields (HIRF) and lightning protection.
To prevent HIRF or lightning from affecting operation by entering via rear connector cables, a HIRF compartment is formed in the rear of the DME Interrogator. The signal and power cables are filtered by using discrete and distributed filter elements and limiting devices on the rear interconnect module located inside HIRF compartment. The filtered lines are then fed to the appropriate points in the DME Interrogator.
The DME Interrogator is packaged in an aluminum casting. This seamless main frame ensures HIRF cannot enter the unit through structural seams. The slots formed by the removable side covers are sealed against HIRF with protective gaskets and metal covers.
The rear connector assembly provides the interwiring from the aircraft interface to the internal modules. A combination of series resistors, series of transient voltage suppressors, and ferrite pin filters provide High Intensity Radiation Fields (HIRF) and lightning protection.
To prevent HIRF or lightning from affecting operation by entering via rear connector cables, a HIRF compartment is formed in the rear of the DME Interrogator. The signal and power cables are filtered by using discrete and distributed filter elements and limiting devices on the rear interconnect module located inside HIRF compartment. The filtered lines are then fed to the appropriate points in the DME Interrogator.
The DME Interrogator is packaged in an aluminum casting. This seamless main frame ensures HIRF cannot enter the unit through structural seams. The slots formed by the removable side covers are sealed against HIRF with protective gaskets and metal covers.
(g) Memory Card Interface Module
The memory card interface module is used to load data into the CPU or record data from the CPU. The memory card interface module supports either flash cards or RAM cards via the front panel Personal Computing Memory Card Interface (PCMCIA) slot. The flash card or RAM card is inserted through the front panel. In one mode, data stored on the flash card memory module is used to update program or data memory in the DME Interrogator. In another mode, the flash card memory module functions as a data recorder.
The memory card interface module is used to load data into the CPU or record data from the CPU. The memory card interface module supports either flash cards or RAM cards via the front panel Personal Computing Memory Card Interface (PCMCIA) slot. The flash card or RAM card is inserted through the front panel. In one mode, data stored on the flash card memory module is used to update program or data memory in the DME Interrogator. In another mode, the flash card memory module functions as a data recorder.
B. DME Antenna
The L-band antenna is an airborne antenna for the DME interrogator. It is a blade type with a radiating cavity driven by capacitive coupling.
This antenna is designed for installation on fast aircraft and operation within the L-band from 960 to 1250 MHz.
The L-band antenna is an airborne antenna for the DME interrogator. It is a blade type with a radiating cavity driven by capacitive coupling.
This antenna is designed for installation on fast aircraft and operation within the L-band from 960 to 1250 MHz.
A. Control
- Each DME interrogator is connected to one RMP. The DME interrogator 1 is connected to the RMP 1 (DME interrogator 2 to RMP 2). The RMP 1 also receives the management bus from the FMGC 1 (RMP 2 from FMGC 2).
- In normal operation the FMGC 1(2) tunes the DME interrogator 1(2) either automatically or manually by means of the MCDU 1(2).
In this case the RMP 1(2) operates as a relay which sends the frequency information from the FMGC 1(2) to the DME interrogator 1(2). - By a second port, the DME interrogator 1(2) receives a second management bus directly from the FMGC 2(1). The interrogator selects one of the two port functions by a discrete signal coming from the FMGC 1(2) through the RMP 1(2).
- In case of one FMGC fault, the other FMGC can control the two DME interrogators, one directly, the other through its RMP.
- In case of the RMP 1(2)fault, the concerned RMP is transparent to data and discrete coming from the FMGC.
- In manual operation (at any time or with failure of the two FMGCs), the RMP 1 can control the DME interrogator 1 after ON NAV mode selection.
Same possibility for the RMP 2 (DME interrogator 2). DME - Frequency Selection in Emergency Mode ** ON A/C NOT FOR ALL DME - Frequency Selection in Emergency Mode ** ON A/C NOT FOR ALL DME - Frequency Selection in Emergency Mode ** ON A/C NOT FOR ALL - In addition, a suppressor coaxial connects the ATC transponders to the DME interrogators. This prevents transmission from one system while the other is in reception mode.
This is necessary because the DME and the ATC systems operate on the same frequency range.
B. Reconfiguration Switching
In normal utilization, the DME 1 and 2 data are shown on both CAPT and F/O NDs through the Display Management Computer (DMC 1(2)). ILS/DME data are shown on both CAPT and F/O PFDs.
In caes of DMC 1(2) fault, it is possible to switch over to the DMC 3 with the EIS DMC selector switch.
This selector switch is located on panel 8VU on the center pedestal.
In this case, the DMC 3 totally replaces the DMC 1(2) through the stage of the output switching relay of the failed DMC.
In case of PFD fault, there is an automatic transfer of the PFD image onto the ND.
In case of ND fault: you obtain the transfer of the ND image onto the PFD when you push the PFD/ND XFR pushbutton switch on panel 301VU (500VU).
When you set the PFD potentiometer to OFF on panel 301VU (500VU), this causes :
In normal utilization, the DME 1 and 2 data are shown on both CAPT and F/O NDs through the Display Management Computer (DMC 1(2)). ILS/DME data are shown on both CAPT and F/O PFDs.
In caes of DMC 1(2) fault, it is possible to switch over to the DMC 3 with the EIS DMC selector switch.
This selector switch is located on panel 8VU on the center pedestal.
In this case, the DMC 3 totally replaces the DMC 1(2) through the stage of the output switching relay of the failed DMC.
In case of PFD fault, there is an automatic transfer of the PFD image onto the ND.
In case of ND fault: you obtain the transfer of the ND image onto the PFD when you push the PFD/ND XFR pushbutton switch on panel 301VU (500VU).
When you set the PFD potentiometer to OFF on panel 301VU (500VU), this causes :
- deactivation of the PFD
- transfer of the PFD image onto the ND.
7. BITE Function
A. Access to DME Sub-menu Functions
It is possible to select the maintenance functions of the DME interrogator 1(2) by pressing the line key adjacent to the SYSTEM REPORT/TEST indication on the CFDS menu, and then selecting the relevant DME on the NAV menu.
After these actions the DME 1(2) provides its own menu page and the sub-menu functions can then be chosen by the operator.
It is possible to select the maintenance functions of the DME interrogator 1(2) by pressing the line key adjacent to the SYSTEM REPORT/TEST indication on the CFDS menu, and then selecting the relevant DME on the NAV menu.
After these actions the DME 1(2) provides its own menu page and the sub-menu functions can then be chosen by the operator.
It is possible to select the maintenance functions of the DME interrogator 1(2) by pressing the line key adjacent to the SYSTEM REPORT/TEST indication on the CFDS menu, and then selecting the relevant DME on the NAV menu.
After these actions the DME 1(2) provides its own menu page and the sub-menu functions can then be chosen by the operator.
It is possible to select the maintenance functions of the DME interrogator 1(2) by pressing the line key adjacent to the SYSTEM REPORT/TEST indication on the CFDS menu, and then selecting the relevant DME on the NAV menu.
After these actions the DME 1(2) provides its own menu page and the sub-menu functions can then be chosen by the operator.
B. Activation of the Test Function
The DME 1(2) test function can be activated in ground conditions only by pressing the line key adjacent to the TEST indication on the DME 1(2) maintenance sub-menu or by pressing the pushbutton switch on the face of the interrogator.
The DME 1(2) test function can be activated in ground conditions only by pressing the line key adjacent to the TEST indication on the DME 1(2) maintenance sub-menu or by pressing the TEST pushbutton switch as designed on the front panel LCD (For more details see para. 7.D.).
The DME 1(2) test function can be activated in ground conditions only by pressing the line key adjacent to the TEST indication on the DME 1(2) maintenance sub-menu or by pressing the pushbutton switch on the face of the interrogator.
The DME 1(2) test function can be activated in ground conditions only by pressing the line key adjacent to the TEST indication on the DME 1(2) maintenance sub-menu or by pressing the TEST pushbutton switch as designed on the front panel LCD (For more details see para. 7.D.).
C. CFDIU Interface
(1) BITE description
The BITE facilitates maintenance on in-service aircraft. It detects and identifies a failure related to the DME system. The BITE of the DME interrogator is connected to the CFDIU (Ref. AMM D/O 31-32-00-00).
The BITE:
The BITE facilitates maintenance on in-service aircraft. It detects and identifies a failure related to the DME system. The BITE of the DME interrogator is connected to the CFDIU (Ref. AMM D/O 31-32-00-00).
The BITE:
- transmits permanently DME system status and its identification message to the CFDIU
- memorizes the failures which occurred during the last 63 flight segments
- monitors data inputs from the various peripherals (FMGC, RMP and CFDIU)
- transmits to the CFDIU the result of the tests performed and self-tests
- can communicate with the CFDIU through the menus.
- the normal mode
- the menu mode
(a) Normal mode
During the normal mode the BITE monitors cyclically the status of the DME system. It transmits its information to the CFDIU during the concerned flight.
In case of fault detection the BITE stores the information in the fault memories.
These items of information are transmitted to the CFDIU every 167 ms by an ARINC 429 message with label 356.
During the normal mode the BITE monitors cyclically the status of the DME system. It transmits its information to the CFDIU during the concerned flight.
In case of fault detection the BITE stores the information in the fault memories.
These items of information are transmitted to the CFDIU every 167 ms by an ARINC 429 message with label 356.
(b) Menu mode
The menu mode can only be activated on the ground.
This mode enables communication between the CFDIU and the DME interrogator BITE by means of the MCDU.
The DME menu mode is composed of:
The menu mode can only be activated on the ground.
This mode enables communication between the CFDIU and the DME interrogator BITE by means of the MCDU.
The DME menu mode is composed of:
- LAST LEG REPORT
- PREVIOUS LEGS REPORT
- LRU IDENTIFICATION
- GND SCANNING
- TROUBLE SHOOTING DATA
- CLASS 3 FAULTS
- GROUND REPORT
- TEST.
(2) Interactive function
The interactive mode can be activated on the ground only, using the line key adjacent to the DME 1 (or 2) indication on the SYSTEM REPORT/TEST page of any MCDU (Ref. AMM D/O 22-82-00-00).
This mode enables communication between the CFDIU and the BITE of the DME interrogator by means of the MCDU.
The interactive mode is composed of:
The interactive mode can be activated on the ground only, using the line key adjacent to the DME 1 (or 2) indication on the SYSTEM REPORT/TEST page of any MCDU (Ref. AMM D/O 22-82-00-00).
This mode enables communication between the CFDIU and the BITE of the DME interrogator by means of the MCDU.
The interactive mode is composed of:
- LAST LEG REPORT This menu contains the fault messages (class 1 and 2, internal and external) detected during the last flight. DME - Maintenance Test Procedure - DME Menu (sheet 1/5) ** ON A/C NOT FOR ALL DME - Maintenance Test Procedure - DME Menu (sheet 1/5) ** ON A/C NOT FOR ALL
- PREVIOUS LEGS REPORT This report contains the fault messages related to the external or internal failures (class 1 and 2) recorded during the previous 63 flight legs. DME - Maintenance Test Procedure - DME Menu (sheet 1/5) ** ON A/C NOT FOR ALL DME - Maintenance Test Procedure - DME Menu (sheet 1/5) ** ON A/C NOT FOR ALL
- LRU IDENTIFICATION Allows to display the P/N and the S/N of the equipment. DME - Maintenance Test Procedure - DME Menu (sheet 1/5) ** ON A/C NOT FOR ALL DME - Maintenance Test Procedure - DME Menu (sheet 1/5) ** ON A/C NOT FOR ALL
- GND SCANNING
Based on the monitoring and fault analysis during flight, provides information of the failures detected while using this function. - TROUBLE SHOOTING DATA
Provides correlation parameters and snapshot data concerning the failure displayed in the LAST LEG REPORT and PREVIOUS LEGS REPORT. - CLASS 3 FAULTS
Allows to display the class 3 faults recorded during the last flight leg. - GROUND REPORT
Allows to present the class 1, 2 or 3 internal failures detected on ground. - TEST. allows a check of the correct operation of the DME interrogator. DME - Maintenance Test Procedure - DME Menu (sheet 4/5) ** ON A/C NOT FOR ALL DME - Maintenance Test Procedure - DME Menu (sheet 4/5) ** ON A/C NOT FOR ALL
(3) List of components
All the components are listed in the Para. 2. Component Location.
All the components are listed in the Para. 2. Component Location.
(4) Reporting function
The tables below give the list of internal/external failures:
The tables below give the list of internal/external failures:
| ------------------------------------------------------------------------------- |
| ! REPORTED INTERNAL FAILURES ! |
| !-----------------------------------------------------------------------------! |
| ! MESSAGE (i = 1 or 2) ! CLASS ! ATA ! |
| !----------------------------------------------------------!-------!----------! |
| ! DME i (2SDi) ! 1 ! 34-51-33 ! |
| ! DME i ANTENNA (3SDi) ! 1 ! 34-51-11 ! |
| ------------------------------------------------------------------------------- |
| ------------------------------------------------------------------------------- |
| ! REPORTED EXTERNAL FAILURES ! |
| !-----------------------------------------------------------------------------! |
| ! MESSAGE (i = 1 or 2) ! CLASS ! ATA ! |
| !----------------------------------------------------------!-------!----------! |
| ! FMGCi(1CA1)/RMPi(1RGi)/DMEi(2SDi) ! 3 ! 22-83-34 ! |
| ! CFDIU(1TW)/DMEi(2SDi) ! 3 ! 31-32-34 ! |
| ! POWER SUPPLY INTERRUPT ! 1 ! 24-00-00 ! |
| ! DMC1/2(1WT1/2)/DDRMI(1FN)/DME1(2SD1) ! 1 ! 31-62-34 ! |
| ! DMC2/1(1WT2/1)/DDRMI(1FN)/DME2(2SD2) ! 1 ! 31-62-34 ! |
| ! LGCIU(5GAi)/DMEi(2SDi) ! 3 ! 32-31-71 ! |
| ------------------------------------------------------------------------------- |
D. BITE Implementation
(1) Internal test processing
| --------------------------------------------------------------------------- |
| ! TEST ! TESTED INTERNAL COMPONENTS ! DURATION ! ACTIVATION ! |
| ! DESIGNATION ! ! ! CONDITIONS ! |
| !----------------!----------------------------!----------!----------------! |
| ! Power-up ! Power supply module ! ! Power interrupt! |
| ! test ! ! ! > 200ms ! |
| !----------------!----------------------------!----------!----------------! |
| ! MCDU system ! - processor board ! ! Relevant MCDU ! |
| ! test ! - receiver ! ! menu line key ! |
| ! ! - synthesizer ! ! selection ! |
| ! ! - power amplifier ! ! ! |
| ! ! - driver ! ! ! |
| ! ! - AGC circuitry ! ! ! |
| !----------------!----------------------------!----------!----------------! |
| ! FACE TEST ! ditto ! ! Relevant P/BSW ! |
| ! ! ! ! activated on ! |
| ! ! ! ! the receiver ! |
| ! ! ! ! face ! |
| --------------------------------------------------------------------------- |
(2) Activation of the test on the indicators
The DME 1(2) test function can be activated only by pressing the pushbutton switch on the face of the interrogator.
The following sequence is then generated on the output of the equipment:
During the first 2 s, the green LRU STATUS and the red CONTROL FAIL LEDs on the face of the interrogator are on.
During the next 2 s, the red LRU STATUS and the red CONTROL FAIL LEDs are on.
During the next 2 s, all LEDs go off.
The green LRU STATUS remains on for 30 s or until the pushbutton switch on the face of the interrogator is pressed and the sequence starts again.
The DME 1(2) test function can be activated only by pressing the pushbutton switch on the face of the interrogator.
The following sequence is then generated on the output of the equipment:
| --------------------------------------------------------------------------- |
| ! DURATION ! MESSAGE ! RMI DISPLAY ! |
| !---------------------!-------------------------!-------------------------! |
| ! 2 s approx. ! FAILURE ! Blanked window ! |
| ! 2 s approx. ! NCD ! Dashed lines ! |
| ! Duration of test ! TEST ! 0.0 ! |
| --------------------------------------------------------------------------- |
During the first 2 s, the green LRU STATUS and the red CONTROL FAIL LEDs on the face of the interrogator are on.
During the next 2 s, the red LRU STATUS and the red CONTROL FAIL LEDs are on.
During the next 2 s, all LEDs go off.
The green LRU STATUS remains on for 30 s or until the pushbutton switch on the face of the interrogator is pressed and the sequence starts again.
(3) Activation of the Self-Test
A functional self-test of the DME Interrogator may be initiated from the normal mode screen by pressing the TEST pushbutton switch as designated on the front panel LCD.
A self-test mode is initiated and a "TEST IN PROGRESS" message is displayed approximately one second after the TEST pushbutton is pressed. This message is displayed for four seconds with a moving thermometer along the bottom of the LCD indicating the progress of the test from one to five seconds.
At the end of the self-test, either a TEST COMPLETE, NO FAILURES message screen or a TEST COMPLETE, FAILURES message screen is displayed. The TEST COMPLETE, NO FAILURES screen contains two pushbutton selections (MAINT and RETURN). The TEST COMPLETE, FAILURES screen also contains two pushbutton selections (MAINT and WHY?).
For both screens, pressing the left (MAINT) pushbutton initiates the extended maintenance pages of the system for troubleshooting. The right (RETURN) pushbutton associated with the TEST COMPLETE, NO FAILURES screen returns the system to its normal mode screen. The right (WHY?) pushbutton associated with the TEST COMPLETE, FAILURES screen places the system in the display-failures mode where individual system failures (fault memory codes) are displayed, one per page.
A functional self-test of the DME Interrogator may be initiated from the normal mode screen by pressing the TEST pushbutton switch as designated on the front panel LCD.
A self-test mode is initiated and a "TEST IN PROGRESS" message is displayed approximately one second after the TEST pushbutton is pressed. This message is displayed for four seconds with a moving thermometer along the bottom of the LCD indicating the progress of the test from one to five seconds.
At the end of the self-test, either a TEST COMPLETE, NO FAILURES message screen or a TEST COMPLETE, FAILURES message screen is displayed. The TEST COMPLETE, NO FAILURES screen contains two pushbutton selections (MAINT and RETURN). The TEST COMPLETE, FAILURES screen also contains two pushbutton selections (MAINT and WHY?).
For both screens, pressing the left (MAINT) pushbutton initiates the extended maintenance pages of the system for troubleshooting. The right (RETURN) pushbutton associated with the TEST COMPLETE, NO FAILURES screen returns the system to its normal mode screen. The right (WHY?) pushbutton associated with the TEST COMPLETE, FAILURES screen places the system in the display-failures mode where individual system failures (fault memory codes) are displayed, one per page.
(4) Internal test processing
| --------------------------------------------------------------------------- |
| ! TEST ! TESTED INTERNAL COMPONENTS ! DURATION ! ACTIVATION ! |
| ! DESIGNATION ! ! ! CONDITIONS ! |
| !----------------!----------------------------!----------!----------------! |
| ! Power-up ! Power supply module ! ! Power interrupt! |
| ! test ! ! ! > 200ms ! |
| !----------------!----------------------------!----------!----------------! |
| ! MCDU system ! - processor board ! ! Relevant MCDU ! |
| ! test ! - receiver ! ! menu line key ! |
| ! ! - synthesizer ! ! selection ! |
| ! ! - power amplifier ! ! ! |
| ! ! - driver ! ! ! |
| ! ! - AGC circuitry ! ! ! |
| !----------------!----------------------------!----------!----------------! |
| ! FACE TEST ! ditto ! ! Relevant P/BSW ! |
| ! ! ! ! activated on ! |
| ! ! ! ! the receiver ! |
| ! ! ! ! face ! |
| --------------------------------------------------------------------------- |
(5) Activation of the test
The DME 1(2) test function can be activated only by pressing the pushbutton switch on the face of the interrogator.
The following sequence is then generated on the output of the equipment:
During the first 2 s, the green LRU STATUS and the red CONTROL FAIL LEDs on the face of the interrogator are on.
During the next 2 s, the red LRU STATUS and the red CONTROL FAIL LEDs are on.
During the next 2 s, all LEDs go off.
The green LRU STATUS remains on for 30 s or until the pushbutton switch on the face of the interrogator is pressed and the sequence starts again.
The DME 1(2) test function can be activated only by pressing the pushbutton switch on the face of the interrogator.
The following sequence is then generated on the output of the equipment:
During the first 2 s, the green LRU STATUS and the red CONTROL FAIL LEDs on the face of the interrogator are on.
During the next 2 s, the red LRU STATUS and the red CONTROL FAIL LEDs are on.
During the next 2 s, all LEDs go off.
The green LRU STATUS remains on for 30 s or until the pushbutton switch on the face of the interrogator is pressed and the sequence starts again.
E. Power-up Tests Initialization and Cockpit Repercussions
(1) Conditions of power-up tests initialization
- How long the computer must be de-energized: 2 s.
- A/C configuration:
- whatever the A/C configuration on ground
(2) Progress of power-up tests
- Duration: 2 s.
- Cockpit repercussions directly linked to power-up test accomplishment (some other repercussions may occur depending on the A/C configuration but these can be disregarded):
- DME RMI display
dashes during 1 s
distance diplayed
(3) Results of power-up tests
(cockpit repercussions, if any, in case of tests pass/tests failed).
(cockpit repercussions, if any, in case of tests pass/tests failed).
- Tests pass:
- DME RMI display
distance displayed
- ND
distance displayed - Tests failed:
- DME RMI display
black
- ND
DME in red
(4) Conditions of power-up tests initialization
- How long the computer must be de-energized: 2 s.
- A/C configuration:
- whatever the A/C configuration on ground
(5) Progress of power-up tests
- Duration: 2 s.
- Cockpit repercussions directly linked to power-up test accomplishment
(6) Results of power-up tests
(cockpit repercussions, if any, in case of tests pass/tests failed).
(cockpit repercussions, if any, in case of tests pass/tests failed).
- Tests pass:
- ND
distance displayed - Tests failed:
- ND
DME in red