W DOC AIRBUS | AMM A320F

MANUAL (MAGNETIC) INDICATORS - DESCRIPTION AND OPERATION


** ON A/C NOT FOR ALL
1. General
The Manual Magnetic Indicators (MMIs) are a secondary direct-reading system used to calculate the fuel quantity in the LH wing, the RH wing and the center tank (when the A/C is on the ground). It is not necessary to have electrical power to use the MMIs. The MMI indications, the aircraft attitude value and the fuel relative density, are used with tables (Ref. 12-11-28) to give the amount of fuel in each tank.
The Manual Magnetic Indicators (MMIs) are a secondary direct-reading system used to calculate the fuel quantity in the LH wing tank, the RH wing tank and the center tank (when the A/C is on the ground). It is not necessary to have electrical power to use the MMIs. The MMI indications, the aircraft attitude value and the fuel relative density, are used with tables (Ref. 12-11-28) to give the amount of fuel in each tank.
NOTE: There are no MMIs in the ACT/s. Thus when the ACT/s is/are installed, this procedure cannot be used to calculate the ACT fuel quantity.
** ON A/C NOT FOR ALL
2. Component Location
F Attitude Monitor ** ON A/C NOT FOR ALL

FIN FUNCTIONAL
DESIGNATION
PANEL ZONE ACCESS
DOOR
ATA REF
** ON A/C NOT FOR ALL
39QM ATT MONITOR-FUEL QUANTITY 192MB 192 28-43-24
** ON A/C NOT FOR ALL
56QM HOUSING-MLI, L WING TK INR 1 540AB 540 28-43-21
57QM HOUSING-MLI, R WING TK INR 1 640AB 640 28-43-21
** ON A/C ALL
58QM HOUSING-MLI, L WING TK INR 2 540BB 540 28-43-21
59QM HOUSING-MLI, R WING TK INR 2 640BB 640 28-43-21
60QM HOUSING-MLI, L WING TK INR 3 540DB 540 28-43-21
61QM HOUSING-MLI, R WING TK INR 3 640DB 640 28-43-21
62QM HOUSING-MLI, L WING TK INR 4 540GB 540 28-43-21
63QM HOUSING-MLI, R WING TK INR 4 640GB 640 28-43-21
91QM HOUSING-MLI, CTR TK LOWER 191 28-43-23
98QM HOUSING-MLI, CTR TK UPPER 147AZ 141 28-43-23
** ON A/C NOT FOR ALL
200QM HOUSING-MLI NO 6 LEFT 540NB 540 28-43-21
201QM HOUSING-MLI NO 6 RIGHT 640NB 640 28-43-21
202QM HOUSING-MLI NO 7 LEFT 540QB 540 28-43-22
203QM HOUSING-MLI NO 7 RIGHT 640QB 640 28-43-22
208QM HOUSING-MLI NO 5 LEFT 540KB 540 28-43-21
209QM HOUSING-MLI NO 5 RIGHT 640KB 640 28-43-21
** ON A/C ALL
92QM MLI-CTR TK 191KB 191 28-43-23
** ON A/C NOT FOR ALL
104QM MLI-L WING TK INR 1 540BB 540 28-43-21
105QM MLI-R WING TK INR 1 640BB 640 28-43-21
** ON A/C ALL
106QM MLI-L WING TK INR 2 540DB 540 28-43-21
107QM MLI-R WING TK INR 2 640DB 640 28-43-21
108QM MLI-L WING TK INR 3 540GB 540 28-43-21
109QM MLI-R WING TK INR 3 640GB 640 28-43-21
110QM MLI-L WING TK INR 4 540KB 540 28-43-21
111QM MLI-R WING TK INR 4 640KB 640 28-43-21
** ON A/C NOT FOR ALL
204QM MLI-NO 6 LEFT 540NB 540 28-43-21
205QM MLI-NO 6 RIGHT 640NB 640 28-43-21
206QM MLI-NO 7 LEFT 540QB 540 28-43-22
207QM MLI-NO 7 RIGHT 640QB 640 28-43-22
210QM MLI-NO 5 LEFT 540KB 540 28-43-21
211QM MLI-NO 5 RIGHT 640KB 640 28-43-21
** ON A/C NOT FOR ALL
64QM HOUSING-MLI, L WING TK OUTR 540AB 540 28-43-22
65QM HOUSING-MLI, R WING TK OUTR 640AB 640 28-43-22
112QM MLI-L WING TK OUTER 540RB 540 28-43-22
113QM MLI-R WING TK OUTER 640RB 640 28-43-22
** ON A/C NOT FOR ALL
3. System Description
F Wing Tank MMI ** ON A/C NOT FOR ALL
F Center Tank MMI ** ON A/C NOT FOR ALL
F Attitude Monitor ** ON A/C NOT FOR ALL
F Center Tank MMI
F Wing Tank MMI ** ON A/C NOT FOR ALL
F Wing Tank MMI ** ON A/C NOT FOR ALL
F Wing Tank MMI ** ON A/C NOT FOR ALL
F Wing Tank MMI ** ON A/C NOT FOR ALL
The wing tank MMIs are in the bottom surface of the wing tanks. The center tank MMI is in the belly fairing directly below the center tank.

The MMIs are as follows:
  • seven in each wing tank
The wing tank MMIs are in the bottom surface of the wing tanks. The center tank MMI is in the belly fairing directly below the center tank.
The attitude monitor 39QM is in the aircraft fuselage.

The MMIs are as follows:
  • five in each wing tank
The wing tank MMIs are in the bottom surface of the wing tanks. The center tank MMI is in the belly fairing directly below the center tank.

The MMIs are as follows:
  • five in each wing tank
The wing tank MMIs are in the bottom surface of the wing tanks. The center tank MMI is in the belly fairing directly below the center tank.

The MMIs are as follows:
  • four in each wing tank
The wing tank MMIs are in the bottom surface of the wing tanks. The center tank MMI is in the belly fairing directly below the center tank.

The MMIs are as follows:
  • three in each wing tank
  • one in the center tank.
Each MMI has a Magnetic Level Indicator (MLI) 104QM thru 111QM, 204QM thru 207QM, 210QM and 211QM. The MLI is contained in its related Magnetic Level-Indicator Housing (MLIH) 56QM thru 63QM, 200QM thru 203QM and 208QM thru 209QM.

Each MMI has a Magnetic Level Indicator (MLI) 104QM thru 113QM. The MLI is contained in its related Magnetic Level-Indicator Housing (MLIH) 56QM thru 65QM.

Each MMI has a Magnetic Level Indicator (MLI) 106QM thru 113QM. The MLI is contained in its related Magnetic Level-Indicator Housing (MLIH) 58QM thru 65QM.

Each MMI has a Magnetic Level Indicator (MLI) 106QM thru 111QM. The MLI is contained in its related Magnetic Level-Indicator Housing (MLIH) 58QM thru 63QM.

The center tank MLI 92QM has two MLIHs. The upper MLIH 98QM is in the bottom skin of the center tank. The lower MLIH 91QM is in the belly fairing immediately below the upper MLIH.

When a MLI is extended from its MLIH, the fuel level in that area of the fuel tank can be measured.

The attitude monitor 39QM is in the belly fairing, behind the access panel 192MB. When the MMIs are used, an aircraft attitude reading is taken from the attitude monitor or the ADIRU or the FQIC input parameters. This reading gives the out-of-level attitude in the pitch and roll axes.
When a MLI is extended from its MLIH, the fuel level in that area of the fuel tank can be measured.

When the MMIs are used, an aircraft attitude reading is taken from the ADIRU or the FQIC input parameters. This reading gives the out-of-level attitude of the aircraft in the pitch and roll axes.
** ON A/C NOT FOR ALL
4. Power Supply
Not applicable
** ON A/C NOT FOR ALL
5. Interfaces
Not applicable
** ON A/C NOT FOR ALL
6. Component Description
The MMI has two components:
  • the MLI
  • the MLIH.
A. MLI
[104QM] [105QM] [106QM] [107QM] [108QM] [109QM] [110QM] [111QM] [204QM] [205QM] [206QM] [210QM] [211QM]

The MLI is made of glass-reinforced plastic and has marks along its length to show fuel levels. At one end of the MLI is a magnet. At the other end is a slot and a bayonet-type lock. The MLI is installed in the MLIH.
104QM thru 113QM

The MLI is made of glass-reinforced plastic and has marks along its length to show fuel levels. At one end of the MLI is a magnet. At the other end is a slot and a bayonet-type lock. The MLI is installed in the MLIH.
106QM thru 113QM

The MLI is made of glass-reinforced plastic and has marks along its length to show fuel levels. At one end of the MLI is a magnet. At the other end is a slot and a bayonet-type lock. The MLI is installed in the MLIH.
106QM thru 111QM

The MLI is made of glass-reinforced plastic and has marks along its length to show fuel levels. At one end of the MLI is a magnet. At the other end is a slot and a bayonet-type lock. The MLI is installed in the MLIH.
B. Magnetic Level Indicator Housing
56QM thru 63QM, 200QM thru 203QM and 208QM thru 209QM

The MLIH has:
  • a tube
  • a float assembly.

56QM thru 65QM

The MLIH has:
  • a tube
  • a float assembly.

58QM thru 65QM

The MLIH has:
  • a tube
  • a float assembly.

58QM thru 63QM

The MLIH has:
  • a tube
  • a float assembly.

Each MLIH assembly is almost the same. The angles of the body mounting-flanges and the MLIH tube lengths are different. An end cap prevents a fuel leakage when the MLI is in use or removed. A body attaches the tube to the fuel tank. The float assembly (which contains a magnet) is free to move up and down the outside of the tube. The MLIH (which fully contains the MLI) has a bayonet-type recess into which the MLI bayonet-lock engages.
C. MLI 92QM (Center Tank)

The center tank MLI is the same type as the wing tank MLIs.
D. Magnetic Level-Indicator Housing (Lower 91QM) (Upper 98QM) (Center Tank)

The center tank MLIH has:
  • two tubes
  • a float assembly
  • an upper-body assembly
  • a lower-body assembly.

The top tube is attached to the upper body assembly. The upper body assembly is on the bottom skin of the fuel tank. An end cap is at the upper end of the top tube. The end cap prevents a fuel leakage when the MLI is in use or removed. The float assembly (which contains a magnet) is free to move up and down the outside of the top tube.

A center body is immediately below the upper body assembly. The lower body assembly is immediately below the center body and is attached to the belly fairing. The center body and the lower body assembly hold the bottom tube. The top and bottom tubes are aligned so that the MLI can move through one tube and into the other. The MLIH has a bayonet-type recess in the lower assembly into which the MLI bayonet-lock engages.
E. Attitude Monitor 39QM

F Attitude Monitor ** ON A/C NOT FOR ALL
The attitude monitor is a circular level with graduations on the surface. Each square of the grid is equal to 0.5 deg. change of attitude. The position of the attitude monitor bubble, in relation to the grid, gives the aircraft attitude.
** ON A/C NOT FOR ALL
7. Operation/Control and Indicating
To measure the quantity of fuel in the wing tanks it is necessary to:
  • extend and read the MLIs
  • measure the attitude of the aircraft (in pitch and roll)
  • measure the relative density of the fuel.

Each MLI is unlocked when it is pressed in and turned through 90 deg. It is then lowered slowly and carefully until it is extended to its maximum length. The MLI is then slowly pushed into its MLIH until a magnetic link is felt between the MLI and the float magnet. The point where the MLI meets the aircraft skin shows the fuel level in that part of the tank. The indication is read and the MLI is pushed fully into its MLIH and locked into position.

A set of mathematical tables (Ref. 12-11-28) are used to find the fuel volume from the MLI value and the aircraft attitude value. When the volume of fuel is known, you must multiply this by the fuel relative density value to get the fuel mass.
A set of mathematical tables (Ref. 12-11-28) are used to find the fuel volume from the MLI value and the aircraft attitude value. When the volume of fuel is known, you must multiply this by the fuel relative density value to get the fuel mass.
NOTE: There are no MMIs in the ACT/s. Thus when the ACT/s is/are installed, this procedure cannot be used to calculate the ACT fuel quantity.
** ON A/C NOT FOR ALL
8. BITE Test
Not applicable
[Rev.10 from 2021] 2026.04.02 06:18:12 UTC