DOC AIRBUS | AMM A320FICE DETECTION - 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
A lighted icing indicator is installed in lieu of one windshield center panel retainer bolt. It is visible by both pilots. Its illumination is controlled by a switch (INT LT/ICE IND & STBY COMPASS) located on the panel 25VU.
The indicator body is made of titanium. The end of the indicator is made of titanium, with openings for lighting.
The ice detection system sends warning messages to the crew when icing conditions and heavy icing are detected.
It also indicates the end of the icing conditions.
This system is inhibited on ground.
The system has two main functions:
** ON A/C NOT FOR ALL A lighted icing indicator is installed in lieu of one windshield center panel retainer bolt. It is visible by both pilots. Its illumination is controlled by a switch (INT LT/ICE IND & STBY COMPASS) located on the panel 25VU.
The indicator body is made of titanium. The end of the indicator is made of titanium, with openings for lighting.
The ice detection system sends warning messages to the crew when icing conditions and heavy icing are detected.
It also indicates the end of the icing conditions.
This system is inhibited on ground.
The system has two main functions:
- better detection of icing conditions
- cutting off of the anti ice system when the latter is no longer necessary (fuel saving).
A lighted icing indicator is installed in lieu of one windshield center panel retainer bolt. It is visible by both pilots. Its illumination is controlled by a switch (INT LT/ICE IND & STBY COMPASS) located on the panel 25VU.
The indicator body is made of titanium. The end of the indicator is made of titanium, with openings for lighting.
2. Component Location
A lighted icing indicator is installed on the center panel retainer between the two windshield panels to appreciate the icing conditions.
The two ice detectors are located on the fuselage forward nose.
A lighted icing indicator is installed on the center panel retainer between the two windshield panels to appreciate the icing conditions.
** ON A/C NOT FOR ALL A lighted icing indicator is installed on the center panel retainer between the two windshield panels to appreciate the icing conditions.
Ice Detector - Component LocationThe two ice detectors are located on the fuselage forward nose.
A lighted icing indicator is installed on the center panel retainer between the two windshield panels to appreciate the icing conditions.
| FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 2DD1 | DET-ICE, L | 122VU | 121 | 30-81-31 | |
| 2DD2 | DET-ICE, R | 121 | 30-81-31 | ||
| ** ON A/C ALL | |||||
| 16DD | IND-LIGHTED, ICING | 211 | 30-81-21 | ||
3. System Description
Not Applicable
The system is composed of two ice detectors, for redundancy.
The detection system is based upon the elementary detection of a small amount of ice build up.
The length of the probe and its location on the aircraft are determined to anticipate safely the icing of the protected areas of the aircraft.
Two levels of detection are provided:
** ON A/C NOT FOR ALL Not Applicable
The system is composed of two ice detectors, for redundancy.
The detection system is based upon the elementary detection of a small amount of ice build up.
The length of the probe and its location on the aircraft are determined to anticipate safely the icing of the protected areas of the aircraft.
Two levels of detection are provided:
- one corresponding to elementary detections is used to generate messages for the engine anti ice
- the other corresponding to a selected number of 7 elementary detections is used to generate messages for the wing anti ice.
4. Power Supply
A. Circuit Breakers
(1) The ice detection system gets the electrical power from the AC main generation of the aircraft.
It is supplied with 115VAC through these circuit breakers.
It is supplied with 115VAC through these circuit breakers.
(2) The icing indicator Lighting is supplied with 28 VDC through this circuit breaker.
| ------------------------------------------------------------------------------- |
| FIN PANEL/LOCATION DESIGNATION BUS AMM ATA REF. |
| P. BLOCK 001 |
| ------------------------------------------------------------------------------- |
| 4DD1 122VU V12 ICE DET 1 103XP 30-81-00 |
| 4DD2 122VU V13 ICE DET 2 202XP 30-81-00 |
| 1LF 49VU LIGHTING/ICE IND/&STBY/ 401PP 30-81-00 |
| COMP LT |
(3) The icing indicator Lighting is supplied with 28 VDC through this circuit breaker.
| ------------------------------------------------------------------------------- |
| FIN PANEL/LOCATION DESIGNATION BUS AMM ATA REF. |
| P. BLOCK 001 |
| ------------------------------------------------------------------------------- |
| 1LF 49VU LIGHTING/ICE IND/&STBY/ 401PP 30-81-00 |
| COMP LT |
5. Interface
Not Applicable
The ice detection system is associated with:
** ON A/C NOT FOR ALL Not Applicable
The ice detection system is associated with:
- Electrical power: AC main generation (Ref. AMM D/O 24-22-00-00),
- the Flight Warning Computer (FWC) (Ref. AMM D/O 31-52-00-00),
- the System Data Acquisition Concentrator (SDAC) (Ref. AMM D/O 31-54-00-00),
- the Centralized Fault Display Interface Unit (CFDIU) (Ref. AMM D/O 31-32-00-00),
- the Multipurpose Control and Display Unit (MCDU) (Ref. AMM D/O 22-82-00-00).
6. Component Description
The ice detection system comprises:
The ice detection system comprises:
- two ENG 1 and ENG 2 pushbutton switches located on the ANTI ICE section of the overhead control and indicating panel 25VU,
- one ANTI ICE/WING pushbutton switch located on the ANTI ICE section of the overhead control and indicating panel 25VU,
- two ice detectors,
- one ICE IND & STBY COMPASS switch located on the INT LT section of the panel 25VU,
- a lighted icing indicator located on the center panel retainer between the two windshield panels.
- one ICE IND & STBY COMPASS switch located on the INT LT section of the panel 25VU,
- a lighted icing indicator located on the center panel retainer between the two windshield panels.
A. ANTI ICE/ENG 1 and ENG 2 Pushbutton Switches
(1) Description
These pushbutton switches control their related engine-air-intake anti ice valve.
These pushbutton switches control their related engine-air-intake anti ice valve.
(a) The blue ON legend comes on when you press the pushbutton switch (ON).
(b) The amber FAULT legend comes on when the pushbutton switch position and the anti ice valve position do not agree.
(2) Ice detection
When icing conditions are detected:
When icing conditions are detected:
- a warning message is displayed on the upper ECAM display unit,
- the MASTER CAUT light comes on,
- the single chime is activated,
(3) Action / result
When the ANTI ICE/ ENG 1(2) pushbutton switch is selected ON, and no more icing conditions are detected, the MEMO message ENG A. ICE begins to pulse, advising to release the ANTI ICE/ENG 1(2) pushbutton switches.
Then the ON legend(s) of the pushbutton switch(es) and the MEMO message go off.
When the ANTI ICE/ ENG 1(2) pushbutton switch is selected ON, and no more icing conditions are detected, the MEMO message ENG A. ICE begins to pulse, advising to release the ANTI ICE/ENG 1(2) pushbutton switches.
Then the ON legend(s) of the pushbutton switch(es) and the MEMO message go off.
B. ANTI ICE/WING Pushbutton Switch
(1) Description
A single pushbutton switch controls both wing anti ice control valves.
A single pushbutton switch controls both wing anti ice control valves.
(a) The blue ON light comes on when you press the pushbutton switch (ON).
(b) The amber FAULT legend comes on when the pushbutton switch position and the anti ice control valve position do not agree.
(2) Ice detection
When severe icing conditions are detected (7 elementary ice detections):
When severe icing conditions are detected (7 elementary ice detections):
- a warning message is displayed on the upper ECAM display unit,
- the MASTER CAUT light comes on,
- the single chime is activated,
(3) Action /result
When the ANTI ICE/WING pushbutton switch is selected ON, and no more icing conditions are detected, the two MEMO messages begin to pulse:
When the ANTI ICE/WING pushbutton switch is selected ON, and no more icing conditions are detected, the two MEMO messages begin to pulse:
- WING A. ICE,
- and ENG A. ICE
- ANTI ICE/ENG 1(2) pushbutton switch,
- and the ANTI ICE/WING pushbutton switch.
C. Ice Detector FIN: 2-DD-1 FIN: 2-DD-2
The ice detector is a probe-type ice detector which is designed to detect natural icing conditions in flight.
The sensing element and the electronic part are grouped in the same unit.
The ice detector has two discrete output signals:
each calibrated to activate at a different level of ice accretion.
The ice detector also provides a discrete output signal (FAULT) for remote display of an ice detector failure.
The ice detector is a probe-type ice detector which is designed to detect natural icing conditions in flight.
The sensing element and the electronic part are grouped in the same unit.
The ice detector has two discrete output signals:
- ICE
- and SEVERITY,
each calibrated to activate at a different level of ice accretion.
The ice detector also provides a discrete output signal (FAULT) for remote display of an ice detector failure.
(1) Strut assembly and sensing element
The probe consists of a magnetostrictive nickel alloy tube of approximately 0.25 in. (6.35 mm) diameter with an exposed length of 1 in. (25.4 mm).
In addition, the strut also contains the drive and feedback coils and probe heaters, and the probe biasing magnetic. The probe vibrates axially at its natural frequency of 40 KHz. As ice accretes on the sensing element, the mass loading affect causes the natural frequency to drop. A 133 Hz drop is correlated to 0.020 plus or minus 0.005 in. (0.508 plus or minus 0.127 mm) of ice and is considered as the detection trip point. When the trip point is reached, the probe is deiced by means of internal heaters to prepare for subsequent detections.
The probe consists of a magnetostrictive nickel alloy tube of approximately 0.25 in. (6.35 mm) diameter with an exposed length of 1 in. (25.4 mm).
In addition, the strut also contains the drive and feedback coils and probe heaters, and the probe biasing magnetic. The probe vibrates axially at its natural frequency of 40 KHz. As ice accretes on the sensing element, the mass loading affect causes the natural frequency to drop. A 133 Hz drop is correlated to 0.020 plus or minus 0.005 in. (0.508 plus or minus 0.127 mm) of ice and is considered as the detection trip point. When the trip point is reached, the probe is deiced by means of internal heaters to prepare for subsequent detections.
(2) Controller (electronic part)
The controller portion of the ice detector contains the electronics necessary to drive and monitor the sensing element, control the input/output signals, provide the built-in test capabilities and convert the input power to the necessary voltages required by the controller electronics.
The controller portion of the ice detector contains the electronics necessary to drive and monitor the sensing element, control the input/output signals, provide the built-in test capabilities and convert the input power to the necessary voltages required by the controller electronics.
(a) Microcomputer
The microcomputer section consists of a microcontroller and asssociated components to provide the required decision processes of the ice detector.
A watchdog timer circuit is used to monitor the correct operation of the microcontroller function. A time out of this circuit will cause the microcontroller to enter the hardware reset state: this enables the FAULT output (FAULT indication) and disables the ICE and SEVERITY outputs.
The microcomputer section consists of a microcontroller and asssociated components to provide the required decision processes of the ice detector.
A watchdog timer circuit is used to monitor the correct operation of the microcontroller function. A time out of this circuit will cause the microcontroller to enter the hardware reset state: this enables the FAULT output (FAULT indication) and disables the ICE and SEVERITY outputs.
(b) Probe oscillator
The probe is driven at its resonant frequency by a closed loop oscillator circuit. This circuit consists of a drive coil and a feedback coil. These coils are mounted concentric with the unexposed half of the probe tube. The drive coil produces a magnetic field which causes the magnetostrictive probe tube to elongate. The relaxation of the tube is picked up by the feedback coil which drives the input of the oscillator operational amplifier setting up the resonant circuit.
The probe is driven at its resonant frequency by a closed loop oscillator circuit. This circuit consists of a drive coil and a feedback coil. These coils are mounted concentric with the unexposed half of the probe tube. The drive coil produces a magnetic field which causes the magnetostrictive probe tube to elongate. The relaxation of the tube is picked up by the feedback coil which drives the input of the oscillator operational amplifier setting up the resonant circuit.
(c) Heater control
The heater control consists of a silicon controlled rectifier with zero cross switching that controls the flow of current through the strut and probe heaters.
The heater control consists of a silicon controlled rectifier with zero cross switching that controls the flow of current through the strut and probe heaters.
D. Detector Inputs
(1) Test inputs
To perform initiated test, the test input must be activated for at least 500 ms. The test input can be initiated several times between energization and de-energization of the aircraft electrical circuits.
To perform initiated test, the test input must be activated for at least 500 ms. The test input can be initiated several times between energization and de-energization of the aircraft electrical circuits.
(2) Reset inputs
The reset input is activated to reset the severity counter and cut off the SEVERITY signal.
In the ice detection system, the reset input receives the wing anti ice valve status. When this valve is open, the SEVERITY signal is reset and its processing is inhibited as long as the wing anti ice is supplied from the aircraft.
The reset input is activated to reset the severity counter and cut off the SEVERITY signal.
In the ice detection system, the reset input receives the wing anti ice valve status. When this valve is open, the SEVERITY signal is reset and its processing is inhibited as long as the wing anti ice is supplied from the aircraft.
E. Detector Outputs
Each ice detector generates three signals:
Each ice detector generates three signals:
(1) ICE signal
The ice detector sends the ICE signal when a thickness of 0.5 mm of ice is accreted on its sensing element. This signal is maintained for 60 seconds. If new ice detections occur within 60 seconds, the ICE signal is maintained for 60 seconds after the last detection.
The ice detector sends the ICE signal when a thickness of 0.5 mm of ice is accreted on its sensing element. This signal is maintained for 60 seconds. If new ice detections occur within 60 seconds, the ICE signal is maintained for 60 seconds after the last detection.
(2) SEVERITY signal
The ice detector generates the SEVERITY signal when a number of ten elementary ice detections is reached.
The threshold for the SEVERITY signal corresponds to approximately 5 mm of ice accreted on the most critical protected surface of the wings (wing tips).
The SEVERITY signal is reset and its processing is inhibited as long as the ice detectors receive an input indicating that the wing anti ice is supplied from the aircraft.
The ice detector generates the SEVERITY signal when a number of ten elementary ice detections is reached.
The threshold for the SEVERITY signal corresponds to approximately 5 mm of ice accreted on the most critical protected surface of the wings (wing tips).
The SEVERITY signal is reset and its processing is inhibited as long as the ice detectors receive an input indicating that the wing anti ice is supplied from the aircraft.
(3) FAULT signal
The ice detector has an internal monitoring to get an appropriate failure rate. A FAULT signal is sent when a fault is detected. In this case, the ICE and SEVERITY signals are inhibited.
The ice detector has an internal monitoring to get an appropriate failure rate. A FAULT signal is sent when a fault is detected. In this case, the ICE and SEVERITY signals are inhibited.
F. Lighted Icing Indicator FIN: 16-DD
A lighted icing indicator is installed in lieu of one winshield center panel retainer bolt. It is visible by both pilots. It provides a visual indication when icing conditions are encountered.
Its illumination is controlled by a switch INT LT/ICE IND & STBY COMPASS (2LF) for night visibility.
A lighted icing indicator is installed in lieu of one winshield center panel retainer bolt. It is visible by both pilots. It provides a visual indication when icing conditions are encountered.
Its illumination is controlled by a switch INT LT/ICE IND & STBY COMPASS (2LF) for night visibility.
7. Operation/Control and Indicating
A. Operation (monitoring)
When icing conditions are detected a discrete signal is generated by the ice detector and transmitted to the cockpit, at the following location:
Then the single chime is activated.
When icing conditions are detected a discrete signal is generated by the ice detector and transmitted to the cockpit, at the following location:
- a message is displayed on the upper ECAM display unit
- MASTER CAUT light comes on.
Then the single chime is activated.
(1) The FAULT signals are sent to the SDAC to provide:
(a) the crew with a caution message (class 1 fault) when both ice detectors are failed
(b) the maintenance crew with a class 2 fault message indicating that one ice detector has failed
(c) illumination of the MASTER CAUT light and activation of the single chime.
(2) The FAULT signals are also sent to the CFDIU.
(3) In addition to this permanent monitoring, the ice detectors perform a test initiated either by power up or by the CFDIU (test input).
For the test initiated by the CFDIU, each of the following signals is activated for two seconds:
If a fault is detected, the FAULT signal remains activated.
For the test initiated by the CFDIU, each of the following signals is activated for two seconds:
- ICE,
- SEVERITY,
- or FAULT.
If a fault is detected, the FAULT signal remains activated.
B. Indicating
The ice detection system is inhibited on the ground in weight-on-wheels configuration (in relation with the LGCIU) because the ice detectors need a minimum relative airspeed, and below 1500 ft, which corresponds to FWC level 2 alerts inhibition phases.
All the above inhibitions originate from the FWC.
The ICE and SEVERITY signals used for the warning messages can be provided by one ice detector or/and the other.
When respectively icing conditions or heavy icing are detected, following warning messages are displayed in amber at the bottom part of the upper ECAM display unit (level 2):
The ice detection system is inhibited on the ground in weight-on-wheels configuration (in relation with the LGCIU) because the ice detectors need a minimum relative airspeed, and below 1500 ft, which corresponds to FWC level 2 alerts inhibition phases.
All the above inhibitions originate from the FWC.
The ICE and SEVERITY signals used for the warning messages can be provided by one ice detector or/and the other.
When respectively icing conditions or heavy icing are detected, following warning messages are displayed in amber at the bottom part of the upper ECAM display unit (level 2):
- ICE DETECTED,
- SEVERE ICE DETECTED.
C. Control
(1) When the engine 1(2) anti ice system is not activated, the following messages are displayed until the corresponding actions are performed:
or
If these messages are not cleared:
| A. ICE ICE DETECTED (amber) |
| - ENG 1 ANTI ICE----ON (cyan) |
| - ENG 2 ANTI ICE----ON (cyan) |
or
| SEVERE ICE DETECTED (amber) |
| - WING ANTI ICE----ON (cyan) |
| - ENG SEL----IGN (cyan) |
If these messages are not cleared:
- A. ICE ICE DETECTED
- SEVERE ICE DETECTED
- ANTI ICE/ENG 1(2) pusbutton switch
- ANTI ICE/WING pushbutton switch.
(2) When the engine 1(2) anti ice system is activated, the ENG A. ICE message is displayed in green on the MEMO item of the upper ECAM display unit.
This indication pulses when:
This indication pulses when:
- the ANTI ICE/ENG 1(2) pushbutton switch has been selected ON,
- no icing conditions have been detected by the ice detectors for 130 seconds,
- one ice detector FAULT signal at least, is correct.
(3) When the wing anti ice system is activated, these messages are displayed in green on the MEMO item of the upper ECAM display unit:
These indications are pulse when:
- ENG A. ICE
- WING A. ICE
These indications are pulse when:
- the ANTI ICE/WING pushbutton switch has been selected ON,
- no icing conditions have been detected by the ice detectors for 130 seconds,
- one ice detector FAULT signal at least, is correct.
A. Description
The function of the BITE is to monitor the operation of the ice detector and the associated ouputs, analyse and confirm the faults and store them in the Non-Volatile Memory (NVM). The ice detector is a type 3 system.
The ice detector incorporates a built-in test feature with remote Initiated Test capability and provides a discrete output signal for remote display of an ice detector failure.
The ice detector BITE performs the following functions:
The BITE is comprised of 3 basic functions:
These functions must check all the ice detector operations to allow an appropriate failure rate to be achieved for the overall system.
In addition to the Initiated Test, the built-in test (normal BITE) continuously monitors the internal components and functions for failure conditions during normal operation.
The function of the BITE is to monitor the operation of the ice detector and the associated ouputs, analyse and confirm the faults and store them in the Non-Volatile Memory (NVM). The ice detector is a type 3 system.
The ice detector incorporates a built-in test feature with remote Initiated Test capability and provides a discrete output signal for remote display of an ice detector failure.
The ice detector BITE performs the following functions:
- acquisition of discrete input signals,
- communication with the SDAC 1(2) and FWC 1(2),
- memorization of failure in a NVM,
- tests.
The BITE is comprised of 3 basic functions:
- Power On Self Test
- Initiated Test
- Normal BITE.
These functions must check all the ice detector operations to allow an appropriate failure rate to be achieved for the overall system.
In addition to the Initiated Test, the built-in test (normal BITE) continuously monitors the internal components and functions for failure conditions during normal operation.
B. Operation
Upon selection from the MCDU, the CFDIU displays the ICE & RAIN menu on the MCDU.
Upon selection from the MCDU, the CFDIU displays the ICE & RAIN menu on the MCDU.
C. Maintenance messages
NOTE: When the failure occurs on the ground, GND precedes the maintenance message.
| ----------------------------------------------------------------------------- |
| MAINTENANCE MESSAGES CLASS INT/EXT ATA REF |
| ----------------------------------------------------------------------------- |
| ICE DETECTOR1 2 I 30-81-00 |
| ICE DETECTOR2 2 I 30-81-00 |