W DOC AIRBUS | AMM A320F

LEAK DETECTION - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL
1. General
F Leak Detection Loops - General Schematic ** ON A/C NOT FOR ALL
F Leak Detection Loops - General Schematic ** ON A/C NOT FOR ALL
This continuous monitoring system is designed to detect, by means of detection loops, any ambient overheat. This is to protect the structures and components near the hot air ducts in the fuselage, pylons and wings, against possible leaks or bursts.
** ON A/C NOT FOR ALL
2. Component Location
F Sensing Element Typical ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
A. Wing Section
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location - Wing ** ON A/C NOT FOR ALL
Components for loop A
FIN FUNCTIONAL
DESIGNATION		 PANEL ZONE ACCESS
DOOR		 ATA REF
** ON A/C NOT FOR ALL
21HF CABLE-CONNECTING, L WING LOOP A 521EB 521 36-22-16
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21HF CABLE-CONNECTING, L WING LOOP A 521 36-22-16
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22HF SNSG ELEM-OVHT, L WING LOOP A 521EB 521 36-22-16
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22HF SNSG ELEM-OVHT, L WING LOOP A 521 36-22-16
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23HF SNSG ELEM-OVHT, L WING LOOP A 521AT 522 36-22-16
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23HF SNSG ELEM-OVHT, L WING LOOP A 522 36-22-16
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24HF CABLE-CONNECTING, L WING LOOP A 521AT 522 36-22-16
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24HF CABLE-CONNECTING, L WING LOOP A 522 36-22-16
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25HF CABLE-CONNECTING, L WING LOOP A 522 36-22-16
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26HF SNSG ELEM-OVHT, L WING LOOP A 522AB 522 36-22-16
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26HF SNSG ELEM-OVHT, L WING LOOP A 522 36-22-16
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27HF SNSG ELEM-OVHT, L WING LOOP A 521AT 522 36-22-16
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27HF SNSG ELEM-OVHT, L WING LOOP A 522 36-22-16
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28HF SNSG ELEM-OVHT, L WING LOOP A 521EB 521 36-22-16
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28HF SNSG ELEM-OVHT, L WING LOOP A 521 36-22-16
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29HF SNSG ELEM-OVHT, L WING LOOP A 521EB 521 36-22-16
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29HF SNSG ELEM-OVHT, L WING LOOP A 521 36-22-16
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49HF SNSG ELEM-OVHT, L WING LOOP B 521EB 521 36-22-16
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49HF SNSG ELEM-OVHT, L WING LOOP B 521 36-22-16
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50HF SNSG ELEM-OVHT, L WING LOOP B 521AT 522 36-22-16
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50HF SNSG ELEM-OVHT, L WING LOOP B 522 36-22-16
** ON A/C NOT FOR ALL
51HF CABLE-CONNECTING, L WING LOOP B 521AT 522 36-22-16
** ON A/C NOT FOR ALL
51HF CABLE-CONNECTING, L WING LOOP B 522 36-22-16
** ON A/C NOT FOR ALL
52HF CABLE-CONNECTING, L WING LOOP B 522AB 522 36-22-16
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52HF CABLE-CONNECTING, L WING LOOP B 522 36-22-16
** ON A/C NOT FOR ALL
53HF SNSG ELEM-OVHT, L WING LOOP B 522AB 522 36-22-16
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53HF SNSG ELEM-OVHT, L WING LOOP B 522 36-22-16
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54HF SNSG ELEM-OVHT, L WING LOOP B 521AT 522 36-22-16
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54HF SNSG ELEM-OVHT, L WING LOOP B 522 36-22-16
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55HF SNSG ELEM-OVHT, L WING LOOP B 521EB 521 36-22-16
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55HF SNSG ELEM-OVHT, L WING LOOP B 521 36-22-16
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56HF SNSG ELEM-OVHT, L WING LOOP B 521AB 521 36-22-16
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56HF SNSG ELEM-OVHT, L WING LOOP B 521 36-22-16
** ON A/C NOT FOR ALL
77HF CABLE-CONNECTING, L WING LOOP B 521AB 521 36-22-16
** ON A/C NOT FOR ALL
77HF CABLE-CONNECTING, L WING LOOP B 521 36-22-16
** ON A/C NOT FOR ALL
37HF CABLE-CONNECTING, R WING LOOP A 621EB 621 36-22-16
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37HF CABLE-CONNECTING, R WING LOOP A 621 36-22-16
** ON A/C NOT FOR ALL
38HF SNSG ELEM-OVHT, R WING LOOP A 621EB 621 36-22-16
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38HF SNSG ELEM-OVHT, R WING LOOP A 621 36-22-16
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39HF SNSG ELEM-OVHT, R WING LOOP A 621AT 622 36-22-16
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39HF SNSG ELEM-OVHT, R WING LOOP A 622 36-22-16
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40HF CABLE-CONNECTING, R WING LOOP A 621AT 622 36-22-16
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40HF CABLE-CONNECTING, R WING LOOP A 622 36-22-16
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41HF CABLE-CONNECTING, R WING LOOP A 622AB 622 36-22-16
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41HF CABLE-CONNECTING, R WING LOOP A 622 36-22-16
** ON A/C NOT FOR ALL
42HF SNSG ELEM-OVHT, R WING LOOP A 622AB 622 36-22-16
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42HF SNSG ELEM-OVHT, R WING LOOP A 622 36-22-16
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43HF SNSG ELEM-OVHT, R WING LOOP A 621AT 622 36-22-16
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43HF SNSG ELEM-OVHT, R WING LOOP A 622 36-22-16
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44HF SNSG ELEM-OVHT, R WING LOOP A 621EB 621 36-22-16
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44HF SNSG ELEM-OVHT, R WING LOOP A 621 36-22-16
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45HF SNSG ELEM-OVHT, R WING LOOP A 621AB 621 36-22-16
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45HF SNSG ELEM-OVHT, R WING LOOP A 621 36-22-16
** ON A/C NOT FOR ALL
64HF CABLE-CONNECTING, R WING LOOP B 621EB 621 36-22-16
** ON A/C NOT FOR ALL
64HF CABLE-CONNECTING, R WING LOOP B 621 36-22-16
** ON A/C NOT FOR ALL
65HF SNSG ELEM-OVHT, R WING LOOP B 621EB 621 36-22-16
** ON A/C NOT FOR ALL
65HF SNSG ELEM-OVHT, R WING LOOP B 621 36-22-16
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66HF SNSG ELEM-OVHT, R WING LOOP B 621AT 622 36-22-16
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66HF SNSG ELEM-OVHT, R WING LOOP B 622 36-22-16
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67HF CABLE-CONNECTING, R WING LOOP B 621AT 622 36-22-16
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67HF CABLE-CONNECTING, R WING LOOP B 622 36-22-16
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68HF CABLE-CONNECTING, R WING LOOP B 622AB 622 36-22-16
** ON A/C NOT FOR ALL
68HF CABLE-CONNECTING, R WING LOOP B 622 36-22-16
** ON A/C NOT FOR ALL
69HF SNSG ELEM-OVHT, R WING LOOP B 622AB 622 36-22-16
** ON A/C NOT FOR ALL
69HF SNSG ELEM-OVHT, R WING LOOP B 622 36-22-16
** ON A/C NOT FOR ALL
70HF SNSG ELEM-OVHT, R WING LOOP B 621AT 622 36-22-16
** ON A/C NOT FOR ALL
70HF SNSG ELEM-OVHT, R WING LOOP B 622 36-22-16
** ON A/C NOT FOR ALL
71HF SNSG ELEM-OVHT, R WING LOOP B 621EB 621 36-22-16
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71HF SNSG ELEM-OVHT, R WING LOOP B 621 36-22-16
** ON A/C NOT FOR ALL
72HF SNSG ELEM-OVHT, R WING LOOP B 621AB 621 36-22-16
** ON A/C NOT FOR ALL
72HF SNSG ELEM-OVHT, R WING LOOP B 621 36-22-16
** ON A/C NOT FOR ALL
80HF SNSG ELEM-OVHT, R WING LOOP A 621AT 621 36-22-16
** ON A/C NOT FOR ALL
80HF SNSG ELEM-OVHT, R WING LOOP A 621 36-22-16
** ON A/C NOT FOR ALL
81HF SNSG ELEM-OVHT, L WING LOOP A 521AT 521 36-22-16
** ON A/C NOT FOR ALL
81HF SNSG ELEM-OVHT, L WING LOOP A 521 36-22-16
** ON A/C NOT FOR ALL
82HF SNSG ELEM-OVHT, R WING LOOP B 621AT 621 36-22-16
** ON A/C NOT FOR ALL
82HF SNSG ELEM-OVHT, R WING LOOP B 621 36-22-16
** ON A/C NOT FOR ALL
83HF SNSG ELEM-OVHT, L WING LOOP B 521AT 521 36-22-16
** ON A/C NOT FOR ALL
83HF SNSG ELEM-OVHT, L WING LOOP B 521 36-22-16
B. MID Fuselage Section
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location - Lower MID Fuselage ** ON A/C NOT FOR ALL
F Component Location - Lower MID Fuselage ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location - Lower MID Fuselage ** ON A/C NOT FOR ALL
FIN FUNCTIONAL
DESIGNATION		 PANEL ZONE ACCESS
DOOR		 ATA REF
** ON A/C NOT FOR ALL
30HF CABLE ASSY 150 36-22-18
31HF OVHT SENS ELEMENT 140 36-22-18
32HF OVERHEAT SENSING ELEM 140 36-22-18
33HF OVHT SENS ELEMENT 140 36-22-18
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34HF OVHT SENS ELEMENT 147FB 140 36-22-18
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34HF OVHT SENS ELEMENT 140 36-22-18
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35HF OVHT SENS ELEMENT 147FB 140 36-22-18
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35HF OVHT SENS ELEMENT 140 36-22-18
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36HF OVHT SENS ELEMENT 147FB 140 36-22-18
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36HF OVHT SENS ELEMENT 140 36-22-18
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47HF ELEMENT-OVERHEAT SENSING 140 36-22-18
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48HF CABLE ASSY 192EB 190 36-22-00
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48HF CABLE ASSY 190 36-22-00
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57HF CABLE ASSY 150 36-22-18
58HF OVHT SENS ELEMENT 140 36-22-18
59HF OVERHEAT SENSING ELEM 140 36-22-18
60HF OVHT SENS ELEMENT 140 36-22-18
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61HF OVHT SENS ELEMENT 147FB 140 36-22-18
** ON A/C NOT FOR ALL
61HF OVHT SENS ELEMENT 140 36-22-18
** ON A/C NOT FOR ALL
62HF OVHT SENS ELEMENT 140 36-22-18
63HF OVHT SENS ELEMENT 140 36-22-18
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73HF OVHT SENS ELEMENT 191EB 140 36-22-18
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73HF OVHT SENS ELEMENT 140 36-22-18
** ON A/C NOT FOR ALL
74HF OVHT SENS ELEMENT 192EB 140 36-22-18
** ON A/C NOT FOR ALL
74HF OVHT SENS ELEMENT 140 36-22-18
** ON A/C NOT FOR ALL
75HF OVHT SENS ELEMENT 140 36-22-18
** ON A/C NOT FOR ALL
76HF CABLE ASSY 192EB 190 36-22-00
** ON A/C NOT FOR ALL
76HF CABLE ASSY 190 36-22-00
** ON A/C NOT FOR ALL
78HF OVHT SENS ELEMENT 140 36-22-18
** ON A/C NOT FOR ALL
79HF OVHT SENS ELEMENT 192EB 140 36-22-18
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79HF OVHT SENS ELEMENT 140 36-22-18
90HF INTERCONNECTING CABLE 140 36-22-16
91HF INTERCONNECTING CABLE 140 36-22-16
92HF INTERCONNECTING CABLE 140 36-22-16
93HF INTERCONNECTING CABLE 140 36-22-16
C. MID and AFT Fuselage Section
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location - Lower MID and AFT Fuselage ** ON A/C NOT FOR ALL
F Component Location - Lower MID and AFT Fuselage ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location - Lower MID and AFT Fuselage ** ON A/C NOT FOR ALL
FIN FUNCTIONAL
DESIGNATION		 PANEL ZONE ACCESS
DOOR		 ATA REF
** ON A/C NOT FOR ALL
11HF SENSING ELEMENT-OVERHEAT,WING 151 36-22-17
12HF OVHT SENS ELEMENT 151 36-22-17
13HF OVHT SENS ELEMENT 151 36-22-17
14HF OVHT SENS ELEMENT 151 36-22-17
15HF OVHT SENS ELEMENT 161 36-22-17
16HF OVHT SENS ELEMENT 171 36-22-17
17HF OVHT SENS ELEMENT 171 36-22-17
** ON A/C NOT FOR ALL
18HF OVHT SENS ELEMENT 312AR 311 36-22-17
** ON A/C NOT FOR ALL
18HF OVHT SENS ELEMENT 311 36-22-17
** ON A/C NOT FOR ALL
19HF OVHT SENS ELEMENT 312AR 311 36-22-17
** ON A/C NOT FOR ALL
19HF OVHT SENS ELEMENT 331 36-22-17
** ON A/C NOT FOR ALL
19HF OVHT SENS ELEMENT 311 36-22-17
** ON A/C NOT FOR ALL
20HF CABLE ASSY 312AR 311 36-22-17
** ON A/C NOT FOR ALL
20HF CABLE ASSY 311 36-22-17
** ON A/C NOT FOR ALL
84HF OVERHEAT SENSING ELEM 150 36-22-17
D. Pylon Section
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location - Pylon ** ON A/C NOT FOR ALL
F Component Location - Pylon ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location ** ON A/C NOT FOR ALL
F Component Location - Pylon ** ON A/C NOT FOR ALL
FIN FUNCTIONAL
DESIGNATION		 PANEL ZONE ACCESS
DOOR		 ATA REF
** ON A/C NOT FOR ALL
1HF1 SNSG ELEM-OVHT, ENG 1 PYLON 471AR 413 36-22-15
1HF2 SNSG ELEM-OVHT, ENG 2 PYLON 481AL 424 36-22-15
** ON A/C NOT FOR ALL
1HF1 SNSG ELEM-OVHT, ENG 1 PYLON 413 36-22-15
1HF2 SNSG ELEM-OVHT, ENG 2 PYLON 424 36-22-15
** ON A/C NOT FOR ALL
2HF1 CABLE-CONNECTING, ENG 1 PYLON 471AR 413 36-22-15
2HF2 CABLE-CONNECTING, ENG 2 PYLON 481AL 424 36-22-15
** ON A/C NOT FOR ALL
2HF1 CABLE-CONNECTING, ENG 1 PYLON 413 36-22-15
2HF2 CABLE-CONNECTING, ENG 2 PYLON 424 36-22-15
** ON A/C NOT FOR ALL
3HF1 CABLE ASSY 413FR 413 36-22-15
3HF2 CABLE ASSY 481AL 424 36-22-15
** ON A/C NOT FOR ALL
3HF1 CABLE ASSY 413 36-22-15
3HF2 CABLE ASSY 424 36-22-15
** ON A/C NOT FOR ALL
3. System Description
F Leak Detection Loops - General Schematic ** ON A/C NOT FOR ALL
F Leak Detection Loops - General Schematic ** ON A/C NOT FOR ALL
The aircraft leak detection system is divided into LH and RH zones by the crossfeed valve in the crossfeed duct at STA1537 (FR35). Each leak detection system operates independently.
Both wing/fuselage leak detection systems are made up of twin loops (A and B) of overheat sensing elements. This eliminates the possibility of incorrect warnings, due to an AND logic.
The overheat sensing elements are installed in each wing along the forward face of the front spar. Clamps and rubber grommets attach the overheat sensing elements at regular intervals along the whole length.
In the fuselage, the elements are installed at STA1537 (FR35) and close to the crossover bleed-air duct. They continue (LH side elements only) up to the APU check valve on the pressurized fuselage between STA2189 and STA2243.
A single loop system is installed along the bleed air duct between the APU check valve and the APU bleed valve.
In each of the pylons, there is a single loop. Each loop is located near the pylon ventilation duct.
** ON A/C NOT FOR ALL
4. Component Description
F Sensing Element Typical ** ON A/C NOT FOR ALL
The overheat sensing elements have a solid nickel center conductor set in a ceramic insulation of porous aluminum oxide. An inconel tube contains these components and is sealed at both ends. Eutectic salt fills the space between the tubing, the ceramic insulation and the center conductor. This mixture is compounded to give a signal at alarm temperature. For the wing and fuselage, the alarm temperature is 124 plus or minus 7 deg.C. The pylon alarm temperature quantity is 204 plus or minus 12 deg.C.
The impedance between the conductor and the outer tubing decreases suddenly when the alarm temperature is reached. At this temperature, the center conductor grounds and gives an alarm signal.
** ON A/C NOT FOR ALL
5. Operation
F Component Location - Pylon ** ON A/C NOT FOR ALL
F Component Location - Pylon ** ON A/C NOT FOR ALL
F Component Location - Cockpit ** ON A/C NOT FOR ALL
F Component Location - Cockpit ** ON A/C NOT FOR ALL
F Leak Detection - Electrical Schematic ** ON A/C NOT FOR ALL
F Leak Detection - Electrical Schematic ** ON A/C NOT FOR ALL
F Leak Detection - Electrical Schematic ** ON A/C NOT FOR ALL
F Leak Detection - Electrical Schematic ** ON A/C NOT FOR ALL
F Leak Detection Logic LH ** ON A/C NOT FOR ALL
F Leak Detector Logic RH ** ON A/C NOT FOR ALL
The overheat sensing elements continuously monitor the surrounding areas for overheat conditions. They are connected in series and detect overheat conditions at any point along the length of the elements. When only a few inches of the elements are heated to the pre-determined temperature, an alarm is caused. When this occurs, the bleed air supply is shut off automatically.
If one loop is inoperative (loop A or B), the remaining loop takes over. If hot air escapes from the bleed air duct and heats an element of the operative loop, a signal is given.
The signal causes:
  • the amber FAULT light on the AIR COND overhead panel to come on,
  • the activation of the ECAM system.
When the ECAM system is activated:
  • the MASTER CAUT lights on the panels 131VU and 130VU come on amber
  • a single chime sounds
  • the message on the upper ECAM display unit comes on
  • the BLEED page on the lower ECAM display unit comes on.
The FAULT light stays on as long as the overheat condition exists. The valves associated with the loop close automatically. If the overheat condition is eliminated, the circuit must be reset to open the valves.
The different FAULT warnings on the AIR COND overhead panel 30VU are:
  • the FAULT legend on the ENG 1 BLEED pushbutton switch which comes on if there is an overheat condition in the LH zone (LH pylon, LH wing and LH MID fuselage),
  • the FAULT legend on the ENG 2 BLEED pushbutton switch which comes on if there is an overheat condition in the RH zone (RH pylon, RH wing and RH MID fuselage),
  • the FAULT legend on the APU BLEED pushbutton switch which comes on if there is an overheat condition in the MID and AFT fuselage (APU duct).
At the same time as the FAULT legend on the ENG 1 BLEED pushbutton switch comes on, the following valves close automatically:
  • the LH pressure regulating valve,
  • the LH wing anti-icing (if the wing anti-icing system is operative) valve,
  • the APU bleed valve (the APU pushbutton switch is in the ON position),
  • the crossbleed valve (the selector is in the AUTO position).
When the FAULT legend on the ENG 2 BLEED pushbutton switch comes on, the following valves close automatically:
  • the RH pressure regulating valve
  • the RH wing anti-icing valve (if the wing anti-icing system is operative)
  • the crossbleed valve (the selector is in the AUTO position).
When the FAULT legend on the APU BLEED pushbutton switch comes on, the APU bleed valve closes automatically (the APU pushbutton switch is in the ON position). Engine start sequence prevents that the APU bleed valve and the crossbleed valve (the selector is in the AUTO position) close.
A functional test can only be carried out on the ground by automatic control activation. It checks the outputs or status of each leak detection loop in-turn. The maintenance test permits the maintenance crew to check a specific function of the system. Additionally, the maintenance test finds a failed Line Replaceable Unit (LRU).
** ON A/C NOT FOR ALL
6. Leak (Overheat) Detection
The two bleed air monitor computers (BMC 1 and BMC 2) monitor the seven detection loops (Loops A and B, LH wing, Loops A and B, RH wing, LH and RH pylon loops and fuselage loop). The indications are given in Chap. 36-20-00.
[Rev.10 from 2021] 2026.04.01 12:37:09 UTC
"Aviabrain" 2025