DOC AIRBUS | AMM A320FTANK VENTING SYSTEM - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these pressures which could cause damage to the fuel tank/aircraft structure. This function is most important:
The operation of the tank venting system is fully automatic. There are no manual controls.
The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these two pressures which can cause damage to the fuel tank/aircraft structure. This function is the most important:
The operation of the tank venting system is fully automatic. There are no manual controls.
The ACT venting system connects the ACT(s) (when it is installed) to the tank venting system.The pipes from the forward ACT(s) and from the aft ACT(s) connect to the center tank vent-pipe. Fuel or fuel vapor in the ACT venting-system pipework is released into the center tank. The ACT venting system is isolated from the tank venting system when the aircraft weight is not on the landing gear.
An electrically operated ACT vent valve is installed in the center tank. When the aircraft weight is not on the landing gear, the vent valve automatically closes. This isolates the ACT venting system from the center tank to pressurize the ACT(s) for fuel transfer (Ref. AMM D/O 28-28-00-00).
When the ACT(s) is (are) not installed, the related pipework in the fuselage is sealed with the caps.
The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these two pressures which can cause damage to the fuel tank/aircraft structure. This function is the most important:
The operation of the tank venting system is fully automatic. There are no manual controls.
The Additional Center Tank (ACT) venting system connects the ACT(s) (when it is installed) to the tank venting system. The pipes from the aft ACT(s) connect to the center tank vent-pipe. Fuel or fuel vapor in the ACT venting-system pipework is released into the center tank. The ACT venting system is isolated from the tank venting system when the aircraft weight is not on the landing gear.
An electrically operated ACT vent valve is installed in the center tank. When the aircraft weight is not on the landing gear, the vent valve automatically closes. This isolates the ACT venting system from the center tank to pressurize the ACT(s) for fuel transfer (Ref. AMM D/O 28-28-00-00).
When the ACT(s) is (are) not installed, the related pipework in the fuselage is sealed with the caps.
The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these pressures which could cause damage to the fuel tank/aircraft structure. This function is most important:
The operation of the tank venting system is fully automatic. There are no manual controls.
The ACT venting system is connected to the center tank. Fuel or fuel gas in the ACT venting system pipework is released into the center tank. When the ACT/s is/are not installed, the related pipework in the fuselage is sealed with caps.
The ACT/s is/are isolated from the center tank in flight so that they can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00). An electrically operated vent valve is installed in each ACT. When the fuel transfer system operates, the vent valves automatically close and air from the cabin pressure control system pressurizes the ACT/s for fuel transfer.
** ON A/C NOT FOR ALL The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these pressures which could cause damage to the fuel tank/aircraft structure. This function is most important:
- during the refuel or defuel operations
- when the aircraft climbs or descends.
The operation of the tank venting system is fully automatic. There are no manual controls.
The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these two pressures which can cause damage to the fuel tank/aircraft structure. This function is the most important:
- During the refuel or defuel operations
- When the aircraft climbs or descends.
The operation of the tank venting system is fully automatic. There are no manual controls.
The ACT venting system connects the ACT(s) (when it is installed) to the tank venting system.The pipes from the forward ACT(s) and from the aft ACT(s) connect to the center tank vent-pipe. Fuel or fuel vapor in the ACT venting-system pipework is released into the center tank. The ACT venting system is isolated from the tank venting system when the aircraft weight is not on the landing gear.
An electrically operated ACT vent valve is installed in the center tank. When the aircraft weight is not on the landing gear, the vent valve automatically closes. This isolates the ACT venting system from the center tank to pressurize the ACT(s) for fuel transfer (Ref. AMM D/O 28-28-00-00).
When the ACT(s) is (are) not installed, the related pipework in the fuselage is sealed with the caps.
The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these two pressures which can cause damage to the fuel tank/aircraft structure. This function is the most important:
- During the refuel or defuel operations
- When the aircraft climbs or descends.
The operation of the tank venting system is fully automatic. There are no manual controls.
The Additional Center Tank (ACT) venting system connects the ACT(s) (when it is installed) to the tank venting system. The pipes from the aft ACT(s) connect to the center tank vent-pipe. Fuel or fuel vapor in the ACT venting-system pipework is released into the center tank. The ACT venting system is isolated from the tank venting system when the aircraft weight is not on the landing gear.
An electrically operated ACT vent valve is installed in the center tank. When the aircraft weight is not on the landing gear, the vent valve automatically closes. This isolates the ACT venting system from the center tank to pressurize the ACT(s) for fuel transfer (Ref. AMM D/O 28-28-00-00).
When the ACT(s) is (are) not installed, the related pipework in the fuselage is sealed with the caps.
The tank venting system keeps the air pressure in the fuel tanks near to the external air pressure. This function prevents a large difference between these pressures which could cause damage to the fuel tank/aircraft structure. This function is most important:
- during the refuel or defuel operations
- when the aircraft climbs or descends.
The operation of the tank venting system is fully automatic. There are no manual controls.
The ACT venting system is connected to the center tank. Fuel or fuel gas in the ACT venting system pipework is released into the center tank. When the ACT/s is/are not installed, the related pipework in the fuselage is sealed with caps.
The ACT/s is/are isolated from the center tank in flight so that they can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00). An electrically operated vent valve is installed in each ACT. When the fuel transfer system operates, the vent valves automatically close and air from the cabin pressure control system pressurizes the ACT/s for fuel transfer.
2. Component Location
Vent System - Component Location ** ON A/C NOT FOR ALL
Vent System - Component Location ** ON A/C NOT FOR ALL
Vent System - Component Location ** ON A/C NOT FOR ALL
Vent System - Component Location ** ON A/C NOT FOR ALL
Vent System - Component Location ** ON A/C NOT FOR ALL
Vent System - Component Location ** ON A/C NOT FOR ALL
Vent Surge Tank ** ON A/C NOT FOR ALL
Vent Surge Tank ** ON A/C NOT FOR ALL
Vent Surge Tank ** ON A/C NOT FOR ALL
Vent Surge Tank ** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL Vent System - Component Location ** ON A/C NOT FOR ALL Vent System - Component Location ** ON A/C NOT FOR ALL Vent System - Component Location ** ON A/C NOT FOR ALL Vent System - Component Location ** ON A/C NOT FOR ALL Vent System - Component Location ** ON A/C NOT FOR ALL Vent System - Component Location ** ON A/C NOT FOR ALL Vent Surge Tank ** ON A/C NOT FOR ALL Vent Surge Tank ** ON A/C NOT FOR ALL Vent Surge Tank ** ON A/C NOT FOR ALL Vent Surge Tank ** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 15QM | VALVE-FLOAT VENT, L WING TK OUTR | 540KB | 540 | 28-12-43 | |
| ** ON A/C NOT FOR ALL | |||||
| 15QM | VALVE-FLOAT VENT, L WING TK OUTR | 540 | 28-12-43 | ||
| ** ON A/C NOT FOR ALL | |||||
| 16QM | VALVE-FLOAT VENT, L WING TK INR | 540JB | 540 | 28-12-43 | |
| ** ON A/C NOT FOR ALL | |||||
| 16QM | VALVE-FLOAT VENT, L WING TK INR | 540 | 28-12-43 | ||
| ** ON A/C NOT FOR ALL | |||||
| 17QM | VALVE-FLOAT VENT, R WING TK INR | 640KB | 640 | 28-12-43 | |
| ** ON A/C NOT FOR ALL | |||||
| 17QM | VALVE-FLOAT VENT, R WING TK INR | 640 | 28-12-43 | ||
| ** ON A/C NOT FOR ALL | |||||
| 18QM | VALVE-FLOAT VENT, R WING TK OUTR | 640JB | 640 | 28-12-43 | |
| ** ON A/C NOT FOR ALL | |||||
| 18QM | VALVE-FLOAT VENT, R WING TK OUTR | 640 | 28-12-43 | ||
| ** ON A/C ALL | |||||
| 46QM | PROTECTOR-OVERPRESSURE, L VENT SURGE TK | 550CB | 550 | 28-12-41 | |
| 47QM | PROTECTOR-OVERPRESSURE, R VENT SURGE TK | 650CB | 650 | 28-12-41 | |
| ** ON A/C NOT FOR ALL | |||||
| 48QM | PROTECTOR-FUEL VENT, L NACA INTAKE | 550AB | 550 | 28-10-00 | |
| 49QM | PROTECTOR-FUEL VENT, R NACA INTAKE | 650AB | 650 | 28-10-00 | |
| ** ON A/C ALL | |||||
| 50QM | CHECK VALVE-FUEL DRAIN, L WING TK INR FWD | 540AB | 540 | 28-12-44 | |
| 51QM | CHECK VALVE-FUEL DRAIN, R WING TK INR FWD | 640AB | 640 | 28-12-44 | |
| ** ON A/C NOT FOR ALL | |||||
| 52QM | CHECK VALVE-FUEL DRAIN, L WING TK OUTR | 540JB | 540 | 28-12-44 | |
| 53QM | CHECK VALVE-FUEL DRAIN, R WING TK OUTR | 640JB | 640 | 28-12-44 | |
| ** ON A/C ALL | |||||
| 93QM | CHECK VALVE-FUEL DRAIN, CTR TK | 147AZ | 141 | 28-12-44 | |
| 96QM | PROTECTOR-OVERPRESSURE, CTR TK | 147AZ | 141 | 28-12-41 | |
| ** ON A/C NOT FOR ALL | |||||
| 102QM | PROTECTOR-OVERPRESSURE, L WING TK | 540PB | 540 | 28-12-41 | |
| 103QM | PROTECTOR-OVERPRESSURE, R WING TK | 640PB | 640 | 28-12-41 | |
| ** ON A/C ALL | |||||
| 120QM | CHECK VALVE-FUEL DRAIN, L WING TK INR REAR | 540AZ | 540 | 28-12-44 | |
| 121QM | CHECK VALVE-FUEL DRAIN, R WING TK INR REAR | 640AZ | 640 | 28-12-44 | |
| ** ON A/C NOT FOR ALL | |||||
| 170QM1 | PROTECTOR-OVERPRESSURE, ACT1 | 826AR | 150 | 28-10-00 | |
| 172QM1 | VALVE-INWARD PRESSURE RELIEF, ACT1 | 826AR | 150 | 28-10-00 | |
| 173QM1 | FUEL DRAIN VALVE | 152 | 28-10-00 | ||
| ** ON A/C NOT FOR ALL | |||||
| 170QM2 | PROTECTOR-OVERPRESSURE, ACT2 | 826AR | 150 | 28-10-00 | |
| 172QM2 | VALVE-INWARD PRESSURE RELIEF, ACT2 | 826AR | 150 | 28-10-00 | |
| 173QM2 | VALVE-FUEL DRAIN, ACT2 | 826AR | 152 | 28-10-00 | |
| ** ON A/C NOT FOR ALL | |||||
| 194QM | PROTECTOR-FUEL VENT, L | 550 | 28-10-00 | ||
| 195QM | PROTECTOR-FUEL VENT, R | 650 | 28-10-00 | ||
| ** ON A/C NOT FOR ALL | |||||
| 191QM1 | VALVE-PRESSURE HOLDING, ACT1 | 150 | 28-28-48 | ||
| ** ON A/C NOT FOR ALL | |||||
| 191QM2 | VALVE-PRESSURE HOLDING, ACT2 | 150 | 28-28-48 | ||
| ** ON A/C NOT FOR ALL | |||||
| 212QM | VALVE-FLOAT VENT, LEFT WING | 540RB | 540 | 28-12-43 | |
| 213QM | VALVE-FLOAT VENT, RIGHT WING | 640RB | 640 | 28-12-43 | |
| ** ON A/C NOT FOR ALL | |||||
| 214QM | CLACK VALVE | 540RB | 540 | 28-11-42 | |
| 215QM | CLACK VALVE | 640RB | 640 | 28-11-42 | |
| 216QM | CLACK VALVE | 540RB | 540 | 28-11-42 | |
| 217QM | CLACK VALVE | 640RB | 640 | 28-11-42 | |
| ** ON A/C NOT FOR ALL | |||||
| 212QM | VALVE-FLOAT VENT, LEFT WING | 540 | 28-12-43 | ||
| 213QM | VALVE-FLOAT VENT, RIGHT WING | 640 | 28-12-43 | ||
| 227QM1 | VALVE-FUEL DRAIN, ACT1 | 152 | 28-21-52 | ||
| 227QM2 | VALVE-FUEL DRAIN, ACT2 | 152 | 28-21-52 | ||
| 229QM1 | VALVE-INWARD PRESSURE RELIEF, ACT1 | 151 | 28-21-52 | ||
| 229QM2 | VALVE-INWARD PRESSURE RELIEF, ACT2 | 151 | 28-21-52 | ||
| 234QM | VALVE-VENT, ACT | 152 | 28-28-62 | ||
| 239QM | CHECK VALVE-ACT VENT, AFT | 152 | 28-28-63 | ||
| ** ON A/C NOT FOR ALL | |||||
| 240QM | CHECK VALVE-ACT VENT, FWD | 152 | 28-28-63 | ||
| 241QM | VALVE-PRESSURE HOLDING, FWD ACT | 152 | 28-28-49 | ||
| ** ON A/C NOT FOR ALL | |||||
| 242QM | VALVE-PRESSURE HOLDING, ACT | 152 | 28-28-49 | ||
| 243QM | VALVE-PRESSURE HOLDING, AFT ACT | 152 | 28-28-49 | ||
| 245QM | VALVE-FUEL DRAIN, ACT | 152 | 28-28-05 | ||
| ** ON A/C NOT FOR ALL | |||||
| 257QM | PROTECTOR-OVERPRESSURE, FWDACT | 152 | 28-12-42 | ||
| ** ON A/C NOT FOR ALL | |||||
| 256QM | PROTECTOR-OVERPRESSURE, AFTACT | 152 | 28-12-42 | ||
| ** ON A/C NOT FOR ALL | |||||
| 260QM | VENT DRAIN VALVE | 141 | 28-21-52 | ||
3. System Description
The tank venting system lets the air in or out of the fuel tanks as necessary. This function lets the fuel storage and the fuel distribution systems operate correctly.
The fuel tank venting system has these components:
When the ACT/s is/are installed the fuel tank venting system also has these components:
The vent protector 48QM(49QM) is installed in the stack pipe. If a ground fire occurs, it prevents the ignition of the fuel vapour in the surge tank (and thus the tank venting-system). It also lets the air flow freely through it in two directions, and prevents ice formation.
If a failure occurs in the fuel system (which causes large quantities of fuel to enter the surge tank), then the vent protector lets the fuel flow freely overboard.
The LH (RH) wing has a vent surge tank (surge tank) between RIB22 and RIB26. The vent surge tank is open to the external air through a stack pipe which is connected to a NACA duct. The NACA duct is on access panel 550AB (650AB) in the bottom of the vent surge tank. The vent surge tank lets the air flow through it in each direction. It is also a temporary reservoir for the fuel that can come into it from the vent pipes. The vent surge tanks have a capacity (before fuel can flow overboard) of 190 l (50 USgal).
Vent protector 194QM (195QM) is installed in the stack pipe. If a ground fire occurs, it prevents the ignition of the fuel vapour in the surge tank (and thus the tank venting-system). It also lets the air flow freely through it in two directions and prevents ice formation.
If a failure occurs in the fuel system (which causes large quantities of fuel to enter the surge tank), then the vent protector lets the fuel flow freely overboard.
Overpressure protector 46QM (47QM) in the vent surge tank makes sure that the pressure in the vent surge tank is not more than the specified limit. If the flow of air into (or out of) the surge tank is blocked, the overpressure protector breaks to release the pressure. If fuel enters the vent surge tank and causes the overpressure protector to break, then this fuel will go overboard. The overpressure protector is installed on access panel 550CB (650CB).
Clack valves 214QM (215QM) and 216QM (217QM) are at the bottom of RIB22 and connect the vent surge tank to the related wing tank. During flight, fuel can collect in the vent surge tank. If this occurs, gravity causes it to move through the clack valves and back into the related wing tank.
During flight, fuel can collect in the vent surge tank. If this occurs, a jet pump (Ref. AMM D/O 28-21-00-00) moves the fuel into the related wing tank outer cell.
Each wing tank and the center tank has a vent system. The vent pipes in the LH wing tank and the center tank connect to the LH vent surge tank through the LH stringer vent duct. The vent pipes in the RH wing tank connect to the RH vent surge tank through the RH stringer vent duct.
The vent for the LH(RH) inner cell between RIB2 and RIB3 is a 63.5 mm (2.5 in.) dia. pipe. One end of the pipe is open and turned to face the upper wing at the highest point adjacent to RIB2/front spar. The other end of the vent pipe is connected to the stringer vent duct outboard of RIB2.
The vent for the LH(RH) inner cell between RIB14 and RIB15 is a 38.1 mm (1.5 in.) dia. pipe. A float valve is connected to the inboard end of the pipe between RIB14 and RIB15. The other end of the vent pipe is connected to the stringer vent duct between RIB17 and RIB18.
The stringer vent duct is an integral pipe that starts inboard of RIB2 and ends in the surge tank at RIB22.
Check valves are installed at the lowest points of the vent pipes and the stringer vent ducts. The check valves let the fuel that has entered the wing tank vent system return to the related wing tank.
Each wing tank and the center tank has a vent system. The vent pipes in the LH wing tank and the center tank connect to the LH vent surge tank through the LH stringer vent duct. The vent pipes in the RH wing tank connect to the RH vent surge tank through the RH stringer vent duct.
The vent for the LH(RH) wing tank between RIB2 and RIB3 is a 63.5 mm (2.5 in.) dia. pipe. One end of the pipe is open and turned to face the upper wing at the highest point adjacent to RIB2/front spar. The other end of the vent pipe is connected to the stringer vent duct outboard of RIB2.
A vent float valve is installed at RIB22. This valve will let air flow between the wing tank and the related surge tank to maintain an equal pressure. The valve will close when the wing tank is full to prevent fuel spills into the surge tank.
The stringer vent duct is an integral pipe that starts inboard of RIB2 and ends in the surge tank at RIB22.
Check valves are installed at the lowest points of the vent pipes and the stringer vent ducts. The check valves let the fuel that has entered the wing tank vent system return to the related wing tank.
The vent for the center tank is a 38.3 mm (1.5 in.) dia. pipe which is open at each end. The pipe has an up-turned end fitting in the center tank to make sure the fuel does not enter the vent pipe. The pipe connects the middle of the center tank to the LH vent surge tank at RIB22. A check valve is installed on the pipe at its lowest point. The check valve lets the fuel that has entered the vent pipe return to the center tank.
The center tank has overpressure protector 96QM installed on the inner face of LH RIB1. The overpressure protector makes sure that the pressure in the center tank is not more than the specified limit. If the pressure in the center tank increases to a specified value, the overpressure protector breaks to release the pressure (into the LH wing tank).
The ACT venting system has these components in the center tank:
The ACT vent pipe connects the ACT air/vapor spaces to the center tank vent-pipe.
ACT vent valve 234QM is electrically operated and closes automatically when the aircraft weight comes off the landing gear. This isolates the ACT venting system so that the ACT(s) can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00). The ACT side of the vent valve is connected to vent pipes from the forward ACT(s) and from the aft ACT(s).
Overpressure protector 256QM is installed in the vent pipe from the aft ACT(s), on the ACT side of check valve 239QM. Overpressure protector 257QM is installed in the vent pipe from the forward ACT, on the ACT side of check valve 240QM. The two overpressure protectors are of the burst disc type. They make sure that the pressure in the ACT venting system does not go above the specified limit. When the burst discs break, pressure in the ACT venting system is released into the center tank.
Check valves 239QM and 240QM are installed in the vent pipes on the ACT side of the vent valve. Check valve 239QM is installed in the vent pipe from the aft ACT(s). Check valve 240QM is installed in the vent pipe from the forward ACT. The check valves are installed to:
Three pressure holding valves 241QM, 242QM and 243QM are installed in the ACT vent pipe. The pressure holding valves prevent high pressure in the ACT(s) as the aircraft climbs. The valves release the pressure into the center tank vent-line at a maximum pressure difference of 0.664 bar (10 psi). Two pressure holding valves (241QM and 243QM) are on the ACT side of the check valves. One pressure holding valve (242QM) is between the check valves, on the ACT side of the vent valve.
Fuel drain check-valve 245QM is installed on the center tank side of the vent valve. The check valve lets fuel and water that collects in the vent pipe drain into the center tank.
The ACT venting system has these components in the center tank:
The ACT vent pipe connects the ACT air/vapor spaces to the center tank vent-pipe.
ACT vent-valve 234QM is electrically operated and closes automatically when the aircraft weight comes off the landing gear. This isolates the ACT venting system so that the ACT(s) can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00). The ACT side of the vent valve is connected to vent pipes from the aft ACT(s).
Overpressure protector 256QM is installed in the vent pipe from the aft ACT(s), on the ACT side of check valve 239QM. Overpressure protector is a burst disc type, it will make sure that the pressure in the ACT venting system does not go above the specified limit. When the burst discs break, pressure in the ACT venting system is released into the center tank.
Aft ACT vent-check-valve 239QM is installed in the vent pipe from the aft ACT(s). The check valve is installed to:
Pressure-holding valves 242QM and 243QM are installed in the ACT vent pipe. Pressure-holding valves prevent high pressure in the ACT(s) as the aircraft climbs. The valves release the pressure into the center tank vent-line at a maximum pressure difference of 0.664 bar (10 psi). Pressure-holding valve 243QM is on the ACT side of the check valve. Pressure-holding valve 242QM is between the check valves, on the ACT side of the vent valve.
Fuel-drain check-valve 245QM lets fuel and water that collects in the vent pipe drain into the center tank.
ACT AFT1 (if installed) has these venting system components that follow:
The tank vent pipe is installed in ACT AFT1, at the top of the tank, parallel to the center line. It connects ACT AFT1 to the center tank. A pressurization pipe is connected to the vent pipe to pressurize the aft ACT(s) for fuel transfer (Ref. AMM D/O 28-28-00-00).
Fuel drain check-valve 227QM1 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into ACT AFT1.
Inward pressure-relief valve 229QM1 is installed in the top wall of the flexible bladder tank. The valve prevents high pressure differences across the flexible bladder tank during descent.
ACT AFT2 (if installed) has these venting system components that follow:
The tank vent pipe is installed in ACT AFT2, at the top of the tank, parallel to the center line. It connects ACT AFT2 to the center tank through ACT AFT1.
Fuel drain check-valve 227QM2 is installed in the tank vent pipe. The check valve lets the fuel that collects in the vent pipe drain into ACT AFT2.
Inward pressure relief-valve 229QM2 is installed in the top wall of the flexible bladder tank. The valve prevents high pressure differences across the flexible bladder tank during descent.
The ACT4.1 (if installed) has venting system components that follow:
The tank vent pipe is installed in the ACT4.1 at the top of the tank. It connects ACT4.1 to the center tank. A pressurization pipe is connected to the vent pipe so that the forward ACT can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00).
The forward ACT sub-system is installed in the rotor burst zone. A detection wire is also installed in this area. The detection wire controls forward vent isolation-valve 232QM (Ref. AMM D/O 28-28-00-00), which is installed in the tank vent pipe. The valve is electrically operated and is open until the detection wire is broken. When the detection wire breaks, the valve closes and the vent pipe of the forward ACT sub-system is isolated.
Overpressure protector 258QM is installed in the tank vent pipe, on the center tank side of the forward vent isolation-valve. The overpressure protector is of the burst disc type. It will break if the pressure in the ACT4.1 goes above the specified limit. This will occur if the forward vent isolation valve is defective and is closed during a refuel.
Fuel drain check-valve 227QM4 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into the ACT4.1.
Inward pressure relief-valve 229QM4 is installed in the top wall of the flexible bladder tank. The valve prevents high pressure differentials across the flexible bladder tank during descent.
When the ACT1 is installed, it is connected to the center tank by a 50 mm (2.0 in.) ACT vent pipe. The vent pipe connects the ACT air/vapour space to the center tank air/vapour space. A shroud on the vent pipe prevents fuel leakage into the fuselage. When the ACT1 is not installed the vent pipe connection in the fuselage is sealed with a cap.
The ACT1 (if installed) contains these venting system components:
The tank vent pipe is installed in the ACT1, at the top of the tank, parallel to the center line. It connects the ACT1 to the center tank through the ACT vent pipe. A pressurization pipe is connected to the tank vent pipe so that the ACT1 can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00).
The vent valve 167QM1 is electrically operated and is closed automatically in flight by the ACT transfer system (Ref. AMM D/O 28-28-00-00). When the vent valve is open, the ACT1 air/vapour space is connected to the center tank air/vapour space. When the vent valve is closed the ACT1 is pressurized for fuel transfer.
The overpressure protector 170QM1 is of the burst disc type and is installed in the tank vent pipe. It makes sure that the pressure in the ACT1 does not go above a specified limit. If the pressure in the ACT1 does go above the specified limit the burst disc breaks and the pressure is released into the vent pipe.
The inward pressure relief valve 172QM1 is installed in the top wall of the tank flexible bladder-bag. The valve prevents high pressure differentials across the tank bag during descent.
The fuel-drain check valve 173QM1 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into the ACT1.
The pressure holding valve 191QM1 is installed in the tank vent pipe. The valve prevents high pressure in the ACT1 during normal (climb) operation. When the ACT pressure goes above 0.25 bar (3.6 psi) above center tank pressure the valve opens to release pressure into the vent system.
The ACT2 (if installed) contains these venting system components:
The tank vent pipe is installed in the ACT2, at the top of the tank, parallel to the center line. It connects the ACT2 to the center tank through the ACT1 tank vent pipe. A pressurization pipe is connected to the tank vent pipe so that the ACT2 can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00).
The vent valve 167QM2 is electrically operated and is closed automatically in flight by the ACT transfer system (Ref. AMM D/O 28-28-00-00). When the vent valve is open, the ACT2 air/vapour space is connected to the center tank air/vapour space. When the vent valve is closed the ACT2 is pressurized for fuel transfer.
The overpressure protector 170QM2 is of the burst disc type and is installed in the tank vent pipe. It makes sure that the pressure in the ACT2 does not go above a specified limit. If the pressure in the ACT2 does go above the specified limit the burst disc breaks and the pressure is released into the vent pipe.
The inward pressure relief valve 172QM2 is installed in the top wall of the tank flexible bladder-bag. The valve prevents high pressure differentials across the tank bag during descent.
The fuel-drain check valve 173QM2 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into the ACT2.
The pressure holding valve 191QM2 is installed in the tank vent pipe. The valve prevents high pressure in the ACT2 during normal (climb) operation. When the ACT pressure goes above 0.25 bar (3.6 psi) above center tank pressure the valve opens to release pressure into the vent system.
** ON A/C NOT FOR ALL The tank venting system lets the air in or out of the fuel tanks as necessary. This function lets the fuel storage and the fuel distribution systems operate correctly.
The fuel tank venting system has these components:
- the vent protector (flame arrestor) 48QM(49QM)
- the surge-tank overpressure protector 46QM(47QM)
- the wing tank overpressure protector
- the center (transfer) tank overpressure protector 96QM
- the wing tank vent float valve 212QM(213QM)
- the check valves 50QM(51QM), 120QM(121QM)
- the clack valves 214QM(215QM), 216QM(217QM).
- the vent protector (flame arrestor) 48QM(49QM)
- the surge-tank overpressure protector 46QM(47QM)
- the wing tank overpressure protector 102QM(103QM)
- the center tank overpressure protector 96QM
- the wing tank vent float valve 15QM(18QM), 16QM(17QM)
- the check valves 50QM(51QM), 52QM(53QM), 93QM, 120QM(121QM).
- the vent protector (flame arrestor) 194QM(195QM)
- the surge-tank overpressure protector 46QM(47QM)
- the wing tank overpressure protector 102QM(103QM)
- the center tank overpressure protector 96QM
- the wing tank vent float valve 15QM(18QM), 16QM(17QM)
- the check valves 50QM(51QM), 52QM(53QM), 93QM, 120QM(121QM).
- Vent protector (flame arrestor) 194QM (195QM)
- Surge-tank overpressure protector 46QM (47QM)
- The wing-tank overpressure protector
- Center (transfer) tank overpressure-protector 96QM
- Wing-tank vent-float valve 212QM (213QM)
- Check valves 50QM (51QM), 120QM (121QM)
- Clack valves 214QM (215QM), 216QM (217QM).
- Vent protector (flame arrestor) 194QM (195QM)
- Surge-tank overpressure protector 46QM (47QM)
- Wing-tank overpressure protector 102QM (103QM)
- Center-tank overpressure protector 96QM
- Wing-tank vent-float valve 16QM (17QM)
- Check valves 50QM (51QM), 52QM (53QM), 93QM, 120QM (121QM).
- the vent protector (flame arrestor) 194QM(195QM)
- the surge-tank overpressure protector 46QM(47QM)
- the wing tank overpressure protector
- the center (transfer) tank overpressure protector 96QM
- the wing tank vent float valve 212QM(213QM)
- the check valves 50QM(51QM), 120QM(121QM), 173QM1
- the clack valves 214QM(215QM), 216QM(217QM)
- the vent drain valve 260QM.
When the ACT/s is/are installed the fuel tank venting system also has these components:
- the ACT1 overpressure protector 170QM1
- the ACT1 inward pressure relief valve 172QM1
- the ACT1 fuel drain valve (check valve) 173QM1
- the ACT1 pressure holding valve 191QM1 (Ref. AMM D/O 28-28-00-00)
- the ACT2 overpressure protector 170QM2
- the ACT2 inward pressure relief valve 172QM2
- the ACT2 fuel drain valve (check valve) 173QM2
- the ACT2 pressure holding valve 191QM2 (Ref. AMM D/O 28-28-00-00).
- the vent protector (flame arrestor) 194QM(195QM)
- the surge-tank overpressure protector 46QM(47QM)
- the wing tank overpressure protector 102QM(103QM)
- the center tank overpressure protector 96QM
- the wing tank vent float valve 15QM(18QM), 16QM(17QM)
- the check valves 50QM(51QM), 52QM(53QM), 93QM, 120QM(121QM), 173QM1
- the inward pressure relief valve 172QM1
- the overpressure protector 170QM1
- the pressure holding valve 191QM1.
The vent protector 48QM(49QM) is installed in the stack pipe. If a ground fire occurs, it prevents the ignition of the fuel vapour in the surge tank (and thus the tank venting-system). It also lets the air flow freely through it in two directions, and prevents ice formation.
If a failure occurs in the fuel system (which causes large quantities of fuel to enter the surge tank), then the vent protector lets the fuel flow freely overboard.
The LH (RH) wing has a vent surge tank (surge tank) between RIB22 and RIB26. The vent surge tank is open to the external air through a stack pipe which is connected to a NACA duct. The NACA duct is on access panel 550AB (650AB) in the bottom of the vent surge tank. The vent surge tank lets the air flow through it in each direction. It is also a temporary reservoir for the fuel that can come into it from the vent pipes. The vent surge tanks have a capacity (before fuel can flow overboard) of 190 l (50 USgal).
Vent protector 194QM (195QM) is installed in the stack pipe. If a ground fire occurs, it prevents the ignition of the fuel vapour in the surge tank (and thus the tank venting-system). It also lets the air flow freely through it in two directions and prevents ice formation.
If a failure occurs in the fuel system (which causes large quantities of fuel to enter the surge tank), then the vent protector lets the fuel flow freely overboard.
Overpressure protector 46QM (47QM) in the vent surge tank makes sure that the pressure in the vent surge tank is not more than the specified limit. If the flow of air into (or out of) the surge tank is blocked, the overpressure protector breaks to release the pressure. If fuel enters the vent surge tank and causes the overpressure protector to break, then this fuel will go overboard. The overpressure protector is installed on access panel 550CB (650CB).
Clack valves 214QM (215QM) and 216QM (217QM) are at the bottom of RIB22 and connect the vent surge tank to the related wing tank. During flight, fuel can collect in the vent surge tank. If this occurs, gravity causes it to move through the clack valves and back into the related wing tank.
During flight, fuel can collect in the vent surge tank. If this occurs, a jet pump (Ref. AMM D/O 28-21-00-00) moves the fuel into the related wing tank outer cell.
Each wing tank and the center tank has a vent system. The vent pipes in the LH wing tank and the center tank connect to the LH vent surge tank through the LH stringer vent duct. The vent pipes in the RH wing tank connect to the RH vent surge tank through the RH stringer vent duct.
The vent for the LH(RH) inner cell between RIB2 and RIB3 is a 63.5 mm (2.5 in.) dia. pipe. One end of the pipe is open and turned to face the upper wing at the highest point adjacent to RIB2/front spar. The other end of the vent pipe is connected to the stringer vent duct outboard of RIB2.
The vent for the LH(RH) inner cell between RIB14 and RIB15 is a 38.1 mm (1.5 in.) dia. pipe. A float valve is connected to the inboard end of the pipe between RIB14 and RIB15. The other end of the vent pipe is connected to the stringer vent duct between RIB17 and RIB18.
The stringer vent duct is an integral pipe that starts inboard of RIB2 and ends in the surge tank at RIB22.
Check valves are installed at the lowest points of the vent pipes and the stringer vent ducts. The check valves let the fuel that has entered the wing tank vent system return to the related wing tank.
Each wing tank and the center tank has a vent system. The vent pipes in the LH wing tank and the center tank connect to the LH vent surge tank through the LH stringer vent duct. The vent pipes in the RH wing tank connect to the RH vent surge tank through the RH stringer vent duct.
The vent for the LH(RH) wing tank between RIB2 and RIB3 is a 63.5 mm (2.5 in.) dia. pipe. One end of the pipe is open and turned to face the upper wing at the highest point adjacent to RIB2/front spar. The other end of the vent pipe is connected to the stringer vent duct outboard of RIB2.
A vent float valve is installed at RIB22. This valve will let air flow between the wing tank and the related surge tank to maintain an equal pressure. The valve will close when the wing tank is full to prevent fuel spills into the surge tank.
The stringer vent duct is an integral pipe that starts inboard of RIB2 and ends in the surge tank at RIB22.
Check valves are installed at the lowest points of the vent pipes and the stringer vent ducts. The check valves let the fuel that has entered the wing tank vent system return to the related wing tank.
The vent for the center tank is a 38.3 mm (1.5 in.) dia. pipe which is open at each end. The pipe has an up-turned end fitting in the center tank to make sure the fuel does not enter the vent pipe. The pipe connects the middle of the center tank to the LH vent surge tank at RIB22. A check valve is installed on the pipe at its lowest point. The check valve lets the fuel that has entered the vent pipe return to the center tank.
The center tank has overpressure protector 96QM installed on the inner face of LH RIB1. The overpressure protector makes sure that the pressure in the center tank is not more than the specified limit. If the pressure in the center tank increases to a specified value, the overpressure protector breaks to release the pressure (into the LH wing tank).
The ACT venting system has these components in the center tank:
- The ACT vent pipe
- ACT vent valve 234QM (Ref. AMM D/O 28-28-00-00)
- Aft ACT overpressure-protector 256QM
- Forward ACT overpressure-protector 257QM
- Aft ACT vent check-valve 239QM (Ref. AMM D/O 28-28-00-00)
- Forward ACT vent check-valve 240QM (Ref. AMM D/O 28-28-00-00)
- Pressure holding valves 241QM, 242QM and 243QM (Ref. AMM D/O 28-28-00-00)
- Fuel drain check-valve 245QM.
The ACT vent pipe connects the ACT air/vapor spaces to the center tank vent-pipe.
ACT vent valve 234QM is electrically operated and closes automatically when the aircraft weight comes off the landing gear. This isolates the ACT venting system so that the ACT(s) can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00). The ACT side of the vent valve is connected to vent pipes from the forward ACT(s) and from the aft ACT(s).
Overpressure protector 256QM is installed in the vent pipe from the aft ACT(s), on the ACT side of check valve 239QM. Overpressure protector 257QM is installed in the vent pipe from the forward ACT, on the ACT side of check valve 240QM. The two overpressure protectors are of the burst disc type. They make sure that the pressure in the ACT venting system does not go above the specified limit. When the burst discs break, pressure in the ACT venting system is released into the center tank.
Check valves 239QM and 240QM are installed in the vent pipes on the ACT side of the vent valve. Check valve 239QM is installed in the vent pipe from the aft ACT(s). Check valve 240QM is installed in the vent pipe from the forward ACT. The check valves are installed to:
- Make sure that fuel from the center tank does not get into the ACT(s)
- Prevent low pressure in the center tank, in descent, when the ACT vent valve is open
- Make sure that fuel from the forward ACT does not get into the aft ACT(s)
- Make sure that fuel from the aft ACT(s) does not get into the forward ACT.
Three pressure holding valves 241QM, 242QM and 243QM are installed in the ACT vent pipe. The pressure holding valves prevent high pressure in the ACT(s) as the aircraft climbs. The valves release the pressure into the center tank vent-line at a maximum pressure difference of 0.664 bar (10 psi). Two pressure holding valves (241QM and 243QM) are on the ACT side of the check valves. One pressure holding valve (242QM) is between the check valves, on the ACT side of the vent valve.
Fuel drain check-valve 245QM is installed on the center tank side of the vent valve. The check valve lets fuel and water that collects in the vent pipe drain into the center tank.
The ACT venting system has these components in the center tank:
- The ACT vent pipe
- ACT vent-valve 234QM (Ref. AMM D/O 28-28-00-00)
- Aft ACT overpressure-protector 256QM
- Aft ACT vent-check-valve 239QM (Ref. AMM D/O 28-28-00-00)
- Pressure-holding valves 242QM and 243QM (Ref. AMM D/O 28-28-00-00)
- Fuel drain-check-valve 245QM.
The ACT vent pipe connects the ACT air/vapor spaces to the center tank vent-pipe.
ACT vent-valve 234QM is electrically operated and closes automatically when the aircraft weight comes off the landing gear. This isolates the ACT venting system so that the ACT(s) can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00). The ACT side of the vent valve is connected to vent pipes from the aft ACT(s).
Overpressure protector 256QM is installed in the vent pipe from the aft ACT(s), on the ACT side of check valve 239QM. Overpressure protector is a burst disc type, it will make sure that the pressure in the ACT venting system does not go above the specified limit. When the burst discs break, pressure in the ACT venting system is released into the center tank.
Aft ACT vent-check-valve 239QM is installed in the vent pipe from the aft ACT(s). The check valve is installed to:
- Make sure that fuel from the center tank does not get into the ACT(s)
- Prevent low pressure in the center tank, in descent, when the ACT vent valve is open.
Pressure-holding valves 242QM and 243QM are installed in the ACT vent pipe. Pressure-holding valves prevent high pressure in the ACT(s) as the aircraft climbs. The valves release the pressure into the center tank vent-line at a maximum pressure difference of 0.664 bar (10 psi). Pressure-holding valve 243QM is on the ACT side of the check valve. Pressure-holding valve 242QM is between the check valves, on the ACT side of the vent valve.
Fuel-drain check-valve 245QM lets fuel and water that collects in the vent pipe drain into the center tank.
ACT AFT1 (if installed) has these venting system components that follow:
- The tank vent pipe
- Fuel drain check-valve 227QM1
- Inward pressure-relief valve 229QM1.
The tank vent pipe is installed in ACT AFT1, at the top of the tank, parallel to the center line. It connects ACT AFT1 to the center tank. A pressurization pipe is connected to the vent pipe to pressurize the aft ACT(s) for fuel transfer (Ref. AMM D/O 28-28-00-00).
Fuel drain check-valve 227QM1 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into ACT AFT1.
Inward pressure-relief valve 229QM1 is installed in the top wall of the flexible bladder tank. The valve prevents high pressure differences across the flexible bladder tank during descent.
ACT AFT2 (if installed) has these venting system components that follow:
- The tank vent pipe
- Fuel drain check-valve 227QM2
- Inward pressure-relief valve 229QM2.
The tank vent pipe is installed in ACT AFT2, at the top of the tank, parallel to the center line. It connects ACT AFT2 to the center tank through ACT AFT1.
Fuel drain check-valve 227QM2 is installed in the tank vent pipe. The check valve lets the fuel that collects in the vent pipe drain into ACT AFT2.
Inward pressure relief-valve 229QM2 is installed in the top wall of the flexible bladder tank. The valve prevents high pressure differences across the flexible bladder tank during descent.
The ACT4.1 (if installed) has venting system components that follow:
- The tank vent pipe
- Forward-ACT vent isolation-valve 232QM (Ref. AMM D/O 28-28-00-00)
- Overpressure protector 258QM
- Fuel drain check-valve 227QM4
- Inward pressure relief-valve 229QM4.
The tank vent pipe is installed in the ACT4.1 at the top of the tank. It connects ACT4.1 to the center tank. A pressurization pipe is connected to the vent pipe so that the forward ACT can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00).
The forward ACT sub-system is installed in the rotor burst zone. A detection wire is also installed in this area. The detection wire controls forward vent isolation-valve 232QM (Ref. AMM D/O 28-28-00-00), which is installed in the tank vent pipe. The valve is electrically operated and is open until the detection wire is broken. When the detection wire breaks, the valve closes and the vent pipe of the forward ACT sub-system is isolated.
Overpressure protector 258QM is installed in the tank vent pipe, on the center tank side of the forward vent isolation-valve. The overpressure protector is of the burst disc type. It will break if the pressure in the ACT4.1 goes above the specified limit. This will occur if the forward vent isolation valve is defective and is closed during a refuel.
Fuel drain check-valve 227QM4 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into the ACT4.1.
Inward pressure relief-valve 229QM4 is installed in the top wall of the flexible bladder tank. The valve prevents high pressure differentials across the flexible bladder tank during descent.
When the ACT1 is installed, it is connected to the center tank by a 50 mm (2.0 in.) ACT vent pipe. The vent pipe connects the ACT air/vapour space to the center tank air/vapour space. A shroud on the vent pipe prevents fuel leakage into the fuselage. When the ACT1 is not installed the vent pipe connection in the fuselage is sealed with a cap.
The ACT1 (if installed) contains these venting system components:
- the tank vent pipe
- the vent valve 167QM1 (Ref. AMM D/O 28-28-00-00)
- the overpressure protector 170QM1
- the inward pressure relief valve 172QM1
- the fuel-drain check valve 173QM1
- the pressure holding valve 191QM1 (Ref. AMM D/O 28-28-00-00).
The tank vent pipe is installed in the ACT1, at the top of the tank, parallel to the center line. It connects the ACT1 to the center tank through the ACT vent pipe. A pressurization pipe is connected to the tank vent pipe so that the ACT1 can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00).
The vent valve 167QM1 is electrically operated and is closed automatically in flight by the ACT transfer system (Ref. AMM D/O 28-28-00-00). When the vent valve is open, the ACT1 air/vapour space is connected to the center tank air/vapour space. When the vent valve is closed the ACT1 is pressurized for fuel transfer.
The overpressure protector 170QM1 is of the burst disc type and is installed in the tank vent pipe. It makes sure that the pressure in the ACT1 does not go above a specified limit. If the pressure in the ACT1 does go above the specified limit the burst disc breaks and the pressure is released into the vent pipe.
The inward pressure relief valve 172QM1 is installed in the top wall of the tank flexible bladder-bag. The valve prevents high pressure differentials across the tank bag during descent.
The fuel-drain check valve 173QM1 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into the ACT1.
The pressure holding valve 191QM1 is installed in the tank vent pipe. The valve prevents high pressure in the ACT1 during normal (climb) operation. When the ACT pressure goes above 0.25 bar (3.6 psi) above center tank pressure the valve opens to release pressure into the vent system.
The ACT2 (if installed) contains these venting system components:
- the tank vent pipe
- the vent valve 167QM2 (Ref. AMM D/O 28-28-00-00)
- the overpressure protector 170QM2
- the inward pressure relief valve 172QM2
- the fuel-drain check valve 173QM2
- the pressure holding valve 191QM2 (Ref. AMM D/O 28-28-00-00).
The tank vent pipe is installed in the ACT2, at the top of the tank, parallel to the center line. It connects the ACT2 to the center tank through the ACT1 tank vent pipe. A pressurization pipe is connected to the tank vent pipe so that the ACT2 can be pressurized for fuel transfer (Ref. AMM D/O 28-28-00-00).
The vent valve 167QM2 is electrically operated and is closed automatically in flight by the ACT transfer system (Ref. AMM D/O 28-28-00-00). When the vent valve is open, the ACT2 air/vapour space is connected to the center tank air/vapour space. When the vent valve is closed the ACT2 is pressurized for fuel transfer.
The overpressure protector 170QM2 is of the burst disc type and is installed in the tank vent pipe. It makes sure that the pressure in the ACT2 does not go above a specified limit. If the pressure in the ACT2 does go above the specified limit the burst disc breaks and the pressure is released into the vent pipe.
The inward pressure relief valve 172QM2 is installed in the top wall of the tank flexible bladder-bag. The valve prevents high pressure differentials across the tank bag during descent.
The fuel-drain check valve 173QM2 is installed in the tank vent pipe. The check valve lets fuel that collects in the vent pipe drain into the ACT2.
The pressure holding valve 191QM2 is installed in the tank vent pipe. The valve prevents high pressure in the ACT2 during normal (climb) operation. When the ACT pressure goes above 0.25 bar (3.6 psi) above center tank pressure the valve opens to release pressure into the vent system.
4. Power Supplies
Not applicable
** ON A/C NOT FOR ALL Not applicable
5. Power Supplies
ACT vent valve 234QM and forward-ACT vent isolation-valve 232QM are included in the ACT transfer system. Refer to (Ref. AMM D/O 28-28-00-00) for power supply data for this system.
ACT vent-valve 234QM is included in the ACT transfer system. Refer to (Ref. AMM D/O 28-28-00-00) for power supply data for this system.
** ON A/C NOT FOR ALL ACT vent valve 234QM and forward-ACT vent isolation-valve 232QM are included in the ACT transfer system. Refer to (Ref. AMM D/O 28-28-00-00) for power supply data for this system.
ACT vent-valve 234QM is included in the ACT transfer system. Refer to (Ref. AMM D/O 28-28-00-00) for power supply data for this system.
6. Interfaces
Not applicable
** ON A/C NOT FOR ALL Not applicable
7. Component Description
A. Overpressure Protector FIN: 46-QM FIN: 47-QM FIN: 96-QM FIN: 102-QM FIN: 103-QM
The primary components of the overpressure protector are:
One end of the body has a mounting flange which attaches it to access panel 550CB (650CB). The burst disc is installed at the other end of the body and is held in place with a flange. The collecting grid is held next to the burst disc with the retaining ring.
If a difference between external pressure and internal pressure occurs (which is more than the permitted tolerance), the burst disc breaks. If the burst disc breaks (because of low internal pressure), then the collecting grid does not let the pieces of the disc go into the vent surge tank.
The burst disc has a white cross painted on its lower side. When you can see this, the burst disc is not broken. The burst disc pressures are given in Table 001.
The primary components of the overpressure protector are:
- A body
- A carbon disc (burst disc)
- A collecting grid with a retaining ring.
One end of the body has a mounting flange which attaches it to access panel 550CB (650CB). The burst disc is installed at the other end of the body and is held in place with a flange. The collecting grid is held next to the burst disc with the retaining ring.
If a difference between external pressure and internal pressure occurs (which is more than the permitted tolerance), the burst disc breaks. If the burst disc breaks (because of low internal pressure), then the collecting grid does not let the pieces of the disc go into the vent surge tank.
The burst disc has a white cross painted on its lower side. When you can see this, the burst disc is not broken. The burst disc pressures are given in Table 001.
| ------------------------------------------------------- |
| ! Burst Disc ! Pressure ! |
| ! Function ! (BAR) (PSI) ! |
| !----------------------!--------------------------------! |
| ! Wing Surge Tank ! ! ! |
| ! Atmosphere to Tank ! 0.20 to 0.30 ! 2.9 to 4.35 ! |
| ! Tank to Atmosphere ! 0.45 to 0.50 ! 6.5 to 7.25 ! |
| ---------------------- --------------- ---------------- |
| Surge Tank Burst-Disc Operation Pressures |
| Table 001 |
B. Overpressure Protector
(On the Access Panel 540HB(640HB))
The primary components of the overpressure protector are:
(On the Access Panel 540PB(640PB))
The primary components of the overpressure protector are:
One end of the body has a mounting flange which attaches it to the access panel 540PB(640PB). The burst disc is located at the other end of the body and is held in place with a flange.
One end of the body has a mounting flange which attaches it to access panel 540HB (640HB). The burst disc is installed at the other end of the body and is held in place with a flange.
If a difference between the external pressure and the internal pressure occurs (which is more than the permitted tolerance) the burst disc breaks.
The burst disc has a white cross painted on its lower side. When you can see this, the burst disc is not broken. The burst disc pressures are given in Table 002.
(On the Access Panel 540HB(640HB))
The primary components of the overpressure protector are:
- a body
- a carbon disc (burst disc)
- an extension tube.
(On the Access Panel 540PB(640PB))
The primary components of the overpressure protector are:
- A body
- A carbon disc (burst disc)
- An extension tube.
One end of the body has a mounting flange which attaches it to the access panel 540PB(640PB). The burst disc is located at the other end of the body and is held in place with a flange.
One end of the body has a mounting flange which attaches it to access panel 540HB (640HB). The burst disc is installed at the other end of the body and is held in place with a flange.
If a difference between the external pressure and the internal pressure occurs (which is more than the permitted tolerance) the burst disc breaks.
The burst disc has a white cross painted on its lower side. When you can see this, the burst disc is not broken. The burst disc pressures are given in Table 002.
| ------------------------------------------------------- |
| ! Burst Disc ! Pressure ! |
| ! Function ! (BAR) (PSI) ! |
| !----------------------!--------------------------------! |
| ! Wing Tank ! ! ! |
| ! Atmosphere to Tank ! 1.26 to 1.54 ! 18.3 to 22.3 ! |
| ! Tank to Atmosphere ! 1.26 to 1.54 ! 18.3 to 22.3 ! |
| ---------------------- --------------- ---------------- |
| Wing Tank Burst-Disc Operation Pressures |
| Table 002 |
C. Overpressure Protector 96QM (Center Tank)
The primary components of the overpressure protector are:
The body has a mounting flange which connects the overpressure protector to the inner face of the LH RIB1. The burst disc is installed in the body between the collecting grid and the basket.
If a center tank to wing tank overpressure occurs, the burst disc breaks to release the pressure to the LH wing tank. The collecting grid prevents the movement of particles into the wing tank. The burst disc pressures are given in the Table 003.
The primary components of the overpressure protector are:
- A body
- A carbon disc (burst disc)
- A basket
- A collecting grid.
The body has a mounting flange which connects the overpressure protector to the inner face of the LH RIB1. The burst disc is installed in the body between the collecting grid and the basket.
If a center tank to wing tank overpressure occurs, the burst disc breaks to release the pressure to the LH wing tank. The collecting grid prevents the movement of particles into the wing tank. The burst disc pressures are given in the Table 003.
| ------------------------------------------------------------- |
| ! Burst Disc ! Pressure ! |
| ! Function ! (BAR) (PSI) ! |
| !-----------------------------!-------------------------------! |
| ! Center Tank to Wing Tank ! 0.69 to 0.75 ! 10.0 to 11.0 ! |
| ------------------------------------------------------------- |
| Center Tank Burst-Disc Operation Pressure |
| Table 003 |
D. Overpressure Protector 102QM(103QM)
The primary components of the overpressure protector are:
The body has a mounting flange which connects the overpressure protector to the outer face of the RIB15. The burst disc is installed in the body between the collecting grid and the basket.
If a wing tank outer cell to a wing tank inner cell overpressure occurs, the burst disc breaks to release the pressure to the wing tank inner cell. The collecting grid prevents the movement of particles into the inner cell. The burst disc pressures are given in the Table 004.
The primary components of the overpressure protector are:
- a body
- a carbon disc (burst disc)
- a basket
- a collecting grid.
The body has a mounting flange which connects the overpressure protector to the outer face of the RIB15. The burst disc is installed in the body between the collecting grid and the basket.
If a wing tank outer cell to a wing tank inner cell overpressure occurs, the burst disc breaks to release the pressure to the wing tank inner cell. The collecting grid prevents the movement of particles into the inner cell. The burst disc pressures are given in the Table 004.
| ------------------------------------------------------------- |
| ! Burst Disc ! Pressure ! |
| ! Function ! (BAR) (PSI) ! |
| !-----------------------------!-------------------------------! |
| ! Outer Cell to Inner Cell ! 0.69 to 0.75 ! 10.0 to 11.0 ! |
| ------------------------------------------------------------- |
| Wing Tank Outer Cell Burst-Disc Operation Pressure |
| Table 004 |
E. Overpressure Protector 256QM and 257QM
The primary components of the overpressure protector are:
The inlet has a mounting flange which connects to a flange on the ACT vent pipe. The burst disc is installed in the outlet. An arrow on the outlet shows the direction of flow.
If the air pressure in the ACT vent pipe is more than the specified value, the burst disc breaks to release the pressure. The burst disc pressure is given in Table 005.
Overpressure protector 256QM
The primary components of the overpressure protector are:
The inlet has a mounting flange which connects to a flange on the ACT vent pipe. The burst disc is installed in the outlet. An arrow on the outlet shows the direction of flow.
If the air pressure in the ACT vent pipe is more than the specified value, the burst disc breaks to release the pressure. The burst disc pressure is given in Table 005.
The primary components of the overpressure protector are:
- An inlet
- An outlet
- A burst disc.
The inlet has a mounting flange which connects to a flange on the ACT vent pipe. The burst disc is installed in the outlet. An arrow on the outlet shows the direction of flow.
If the air pressure in the ACT vent pipe is more than the specified value, the burst disc breaks to release the pressure. The burst disc pressure is given in Table 005.
| ------------------------------------------------------------- |
| ! Burst Disc ! Pressure ! |
| ! ! (BAR) (PSI) ! |
| !----------------------------- !------------------------------! |
| ! ACT Vent Pipe to Center Tank ! 0.83 to 1.1 ! 12.0 to 16.0 ! |
| ------------------------------------------------------------- |
| ACT Vent Pipe Burst-Disc Operation Pressure |
| Table 005 |
Overpressure protector 256QM
The primary components of the overpressure protector are:
- An inlet
- An outlet
- A burst disc.
The inlet has a mounting flange which connects to a flange on the ACT vent pipe. The burst disc is installed in the outlet. An arrow on the outlet shows the direction of flow.
If the air pressure in the ACT vent pipe is more than the specified value, the burst disc breaks to release the pressure. The burst disc pressure is given in Table 005.
| ------------------------------------------------------------- |
| ! Burst Disc ! Pressure ! |
| ! ! (BAR) (PSI) ! |
| !----------------------------- !------------------------------! |
| ! ACT Vent Pipe to Center Tank ! 0.83 to 1.1 ! 12.0 to 16.0 ! |
| ------------------------------------------------------------- |
| ACT Vent Pipe Burst-Disc Operation Pressure |
| Table 005 |
F. Overpressure Protector
170QM1 (in the ACT1 - when installed)
170QM2 (in the ACT2 - when installed)
The primary components of the overpressure protector are:
The outlet has a mounting flange which connects to a flange on the ACT tank vent pipe. The burst disc is installed in the inlet and an arrow on the outlet shows the direction of flow.
If the air pressure in the ACT is more than the specified value, the burst disc breaks open to release the pressure. The burst disc pressures are given in the Table 004.
170QM1 (in the ACT1 - when installed)
170QM2 (in the ACT2 - when installed)
The primary components of the overpressure protector are:
- an inlet
- an outlet
- a burst disc.
The outlet has a mounting flange which connects to a flange on the ACT tank vent pipe. The burst disc is installed in the inlet and an arrow on the outlet shows the direction of flow.
If the air pressure in the ACT is more than the specified value, the burst disc breaks open to release the pressure. The burst disc pressures are given in the Table 004.
| ------------------------------------------------------------- |
| ! Burst Disc ! Pressure ! |
| ! ! (BAR) (PSI) ! |
| !-----------------------------!-------------------------------! |
| ! ACT to Center Tank ! 0.62 to 0.90 ! 9.0 to 13.0 ! |
| ------------------------------------------------------------- |
| ACT1/ACT2 Burst-Disc Operation Pressure |
| Table 004 |
G. Vent Protector
48QM(49QM)
The primary components of the vent protector are:
The body has a flange at both ends which connects to the NACA intake. The ice protector and the flame arrestor are located in the body on a flange. A locking ring holds the ice protector and the flame arrestor in position.
194QM(195QM)
The primary components of the vent protector are:
The body has a flange at both ends which connects to the NACA intake. The ice protector and the flame arrestor are installed in the body on a flange. A locking ring holds the ice protector and the flame arrestor in position.
48QM(49QM)
The primary components of the vent protector are:
- a body
- an ice protector
- a flame arrestor.
The body has a flange at both ends which connects to the NACA intake. The ice protector and the flame arrestor are located in the body on a flange. A locking ring holds the ice protector and the flame arrestor in position.
194QM(195QM)
The primary components of the vent protector are:
- A body
- An ice protector
- A flame arrestor.
The body has a flange at both ends which connects to the NACA intake. The ice protector and the flame arrestor are installed in the body on a flange. A locking ring holds the ice protector and the flame arrestor in position.
H. Vent Float Valve
212QM(213QM)
The primary components of the vent float valve are:
The body is open at each end. One end of the body connects to RIB 22 by a flange. A valve plate is located on the arm of the float assembly and the float assembly attaches to a hinge lug on the body. The float assembly usually hangs down which keeps the valve open. When the fuel lifts the float assembly the valve plate closes the valve.
15QM(18QM), 16QM(17QM)
The primary components of the vent float valve are:
The body is open at each end. One end of the body has a flange for installation. A valve plate is located on the arm of the float assembly and the float assembly attaches to a hinge lug on the body. The float assembly usually hangs down which keeps the valve open. When the fuel lifts the float assembly the valve plate closes the valve.
16QM (17QM)
The primary components of the vent float valve are:
The body is open at each end. One end of the body has a flange for installation. A valve plate is located on the arm of the float assembly and the float assembly attaches to a hinge lug on the body. The float assembly usually hangs down which keeps the valve open. When the fuel lifts the float assembly, the valve plate closes the valve.
212QM(213QM)
The primary components of the vent float valve are:
- A body
- An arm assembly
- A float
The body is open at each end. One end of the body connects to RIB 22 by a flange. A valve plate is located on the arm of the float assembly and the float assembly attaches to a hinge lug on the body. The float assembly usually hangs down which keeps the valve open. When the fuel lifts the float assembly the valve plate closes the valve.
15QM(18QM), 16QM(17QM)
The primary components of the vent float valve are:
- a body
- a arm assembly
- a float
The body is open at each end. One end of the body has a flange for installation. A valve plate is located on the arm of the float assembly and the float assembly attaches to a hinge lug on the body. The float assembly usually hangs down which keeps the valve open. When the fuel lifts the float assembly the valve plate closes the valve.
16QM (17QM)
The primary components of the vent float valve are:
- A body
- An arm assembly
- A float.
The body is open at each end. One end of the body has a flange for installation. A valve plate is located on the arm of the float assembly and the float assembly attaches to a hinge lug on the body. The float assembly usually hangs down which keeps the valve open. When the fuel lifts the float assembly, the valve plate closes the valve.
I. Clack Valve 214QM(215QM), 216QM(217QM)
The clack valve has components that follow:
The clack valve has components that follow:
- A body
- A valve plate and pin
The body has a hole through the center and is attached to RIB22 with four bolts. The pin attaches the valve plate to the body. The valve plate hangs down in the closed position. The clack valve lets fuel flow in one direction only.
J. Inward Pressure Relief Valve
172QM1 (in the ACT1 - when installed)
172QM2 (in the ACT2 - when installed)
The ACT inward pressure relief valve has:
172QM1 (in the ACT1 - when installed)
172QM2 (in the ACT2 - when installed)
The ACT inward pressure relief valve has:
- a body
- a spring
- a valve plate assembly.
K. Inward Pressure Relief Valve 229QM*
The ACT inward pressure-relief valve has components that follow:
The ACT inward pressure-relief valve has components that follow:
- A body
- A spring
- A valve plate assembly.
L. Fuel Drain Check Valve 50QM(51QM), 52QM(53QM), 93QM, 120QM(121QM), 227QM*
Venting System - Component Location (with ACT provision) ** ON A/C NOT FOR ALL
Venting System - Component Location (with ACT(s) installed) ** ON A/C NOT FOR ALL
Venting System - Component Location (with ACT provision) ** ON A/C NOT FOR ALL
Venting System - Component Location (with ACT(s) installed) ** ON A/C NOT FOR ALL
The fuel drain check-valve is connected to the vent pipe and is made of the rubber tube. The tube is circular at the valve inlet which is attached to the vent pipe with a clamp. The rubber at the valve outlet is compressed to make a lipped valve. The valve is usually closed to prevent the flow of the fuel back into the vent pipe.
When fuel comes into the check valve, it is held there until the pressure is sufficient to open the lips of the valve. The fuel then flows into the fuel tank.
Venting System - Component Location (with ACT provision) ** ON A/C NOT FOR ALL Venting System - Component Location (with ACT(s) installed) ** ON A/C NOT FOR ALL Venting System - Component Location (with ACT provision) ** ON A/C NOT FOR ALL Venting System - Component Location (with ACT(s) installed) ** ON A/C NOT FOR ALL The fuel drain check-valve is connected to the vent pipe and is made of the rubber tube. The tube is circular at the valve inlet which is attached to the vent pipe with a clamp. The rubber at the valve outlet is compressed to make a lipped valve. The valve is usually closed to prevent the flow of the fuel back into the vent pipe.
When fuel comes into the check valve, it is held there until the pressure is sufficient to open the lips of the valve. The fuel then flows into the fuel tank.
M. Fuel Drain Check Valve
50QM(51QM), 93QM, 120QM(121QM), 173QM1, 173QM2
The check valves are installed as follows:
The fuel drain check valve is connected to the vent pipe and is made from rubber tube. The tube is circular at the valve inlet which is attached to the vent pipe with a clamp. The rubber at the valve outlet is compressed to make a lipped valve. The valve is usually closed to prevent the flow of fuel back into the vent pipe.
When fuel comes into the check valve it is held there until the pressure is sufficient to open lips of the valve. The fuel then flows into the fuel tank.
50QM(51QM), 93QM, 120QM(121QM), 173QM1, 173QM2
The check valves are installed as follows:
- 50QM(51QM) and 120QM(121QM) in the wing tank
- 93QM in the center tank
- 173QM1 in the ACT1 (when installed)
- 173QM2 in the ACT2 (when installed).
The fuel drain check valve is connected to the vent pipe and is made from rubber tube. The tube is circular at the valve inlet which is attached to the vent pipe with a clamp. The rubber at the valve outlet is compressed to make a lipped valve. The valve is usually closed to prevent the flow of fuel back into the vent pipe.
When fuel comes into the check valve it is held there until the pressure is sufficient to open lips of the valve. The fuel then flows into the fuel tank.
8. Operation/Control and Indicating
The operation of the tank venting system is fully automatic. There is no manual control of the system and the system gives no indications.
** ON A/C NOT FOR ALL The operation of the tank venting system is fully automatic. There is no manual control of the system and the system gives no indications.
9. BITE Test
Not applicable
Not applicable