DOC AIRBUS | AMM A320FFORWARD CARGO COMPARTMENT DOOR - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The FWD cargo-compartment door (zone 825) is installed on the lower right side of the fuselage between FR24A and FR28. It opens hydraulically out from the fuselage and gives access to the FWD cargo compartment. It is permitted to operate the cargo door with the subsequent wind speed limits:
** ON A/C NOT FOR ALL The FWD cargo-compartment door (zone 825) is installed on the lower right side of the fuselage between FR24A and FR28. It opens hydraulically out from the fuselage and gives access to the FWD cargo compartment. It is permitted to operate the cargo door with the subsequent wind speed limits:
- Usual operation of the cargo door: 40 knots maximum
- Operation of the cargo door with the nose of the A/C into wind: 50 knots maximum
- The cargo door can stay in the fully open position: 65 knots maximum.
The cargo door has a manually operated locking and latching mechanism which keeps it in the closed position and locks it.
The cargo door weighs 116.0 kg (255.7362 lb) and has dimensions of 1855 x 2025 mm (73 x 80 in.).
2. Component Location
FWD Cargo-Compartment Door (Zone 825) - Component Location ** ON A/C NOT FOR ALL
FWD Cargo-Compartment Door (Zone 825) - Component Location ** ON A/C NOT FOR ALL
FWD Cargo-Compartment Door - Component Location ** ON A/C NOT FOR ALL
FWD Cargo-Compartment Door - Component Location ** ON A/C NOT FOR ALL
FWD Cargo-Compartment Door (Zone 825) - Component Location ** ON A/C NOT FOR ALL FWD Cargo-Compartment Door (Zone 825) - Component Location ** ON A/C NOT FOR ALL FWD Cargo-Compartment Door - Component Location ** ON A/C NOT FOR ALL FWD Cargo-Compartment Door - Component Location ** ON A/C NOT FOR ALL ** ON A/C NOT FOR ALL
3. System Description
The FWD cargo- compartment door (referred to as cargo door) is a hollow alloy construction with a structure of sheet metal and machined parts.
The door-to-fuselage connection is of piano hinges which transmits the load of the cargo door to the fuselage.
The latching hooks of the manually operated latching mechanism keep each cargo door in the closed position. The lock cams of the locking mechanism engage with the latching hooks when the cargo doors are correctly locked.
To show this condition there are indication windows in the access panel of each cargo door. The green mark on each lock cam shows that the locking mechanism blocks each latching unit in its latched position. The red marks show that the latching units are not blocked and satisfactory.
When the cargo door is locked, the door seal makes the related cargo compartment pressure-tight. To balance the difference in pressure on the ground and in the cargo compartment, there is a vent door in the cargo door. This spring-loaded vent door opens inboard and remains in this position until the cargo door is correctly locked.
The interlock mechanism blocks the latching mechanism in the unlatched position when the cargo door is not closed. Then the door handle is not movable and the latching hooks stay in the lifted position.
The door actuators use hydraulic pressure from the door hydraulic system to open and close the cargo doors. They have an internal locking mechanism to keep the cargo door safely in the fully open position.
The proximity switches of the door warning system (circuit WV) monitor the closed and locked condition of the cargo door. They send a signal to the Electronic Centralized Aircraft Monitoring (ECAM) system when a cargo door is not locked. Then the master caution lights in the cockpit come on and the data is shown on the DOOR page of the ECAM display.
The external indications which show that a cargo door is not correctly locked and latched are:
** ON A/C NOT FOR ALL The FWD cargo- compartment door (referred to as cargo door) is a hollow alloy construction with a structure of sheet metal and machined parts.
The door-to-fuselage connection is of piano hinges which transmits the load of the cargo door to the fuselage.
The latching hooks of the manually operated latching mechanism keep each cargo door in the closed position. The lock cams of the locking mechanism engage with the latching hooks when the cargo doors are correctly locked.
To show this condition there are indication windows in the access panel of each cargo door. The green mark on each lock cam shows that the locking mechanism blocks each latching unit in its latched position. The red marks show that the latching units are not blocked and satisfactory.
When the cargo door is locked, the door seal makes the related cargo compartment pressure-tight. To balance the difference in pressure on the ground and in the cargo compartment, there is a vent door in the cargo door. This spring-loaded vent door opens inboard and remains in this position until the cargo door is correctly locked.
The interlock mechanism blocks the latching mechanism in the unlatched position when the cargo door is not closed. Then the door handle is not movable and the latching hooks stay in the lifted position.
The door actuators use hydraulic pressure from the door hydraulic system to open and close the cargo doors. They have an internal locking mechanism to keep the cargo door safely in the fully open position.
The proximity switches of the door warning system (circuit WV) monitor the closed and locked condition of the cargo door. They send a signal to the Electronic Centralized Aircraft Monitoring (ECAM) system when a cargo door is not locked. Then the master caution lights in the cockpit come on and the data is shown on the DOOR page of the ECAM display.
The external indications which show that a cargo door is not correctly locked and latched are:
- the vent door stays in open position,
- the door handle stays away from the outer contour of the cargo door,
- the red mark of each lock cams is in view through the indication windows.
4. Component Description
A. Door Structure
The primary structure has vertical and horizontal edge members, fairings, longitudinal beams, frames, and an inner and outer skin. These formed and milled components are made from aluminum alloy and are riveted together with a sealant compound to make a corrosion-resistant cargo door. The sealant compound between the skin and the edge members makes sure that the primary structure is pressure-tight.
To prevent corrosion, all components have a surface protection of chromic acid anodizing plus epoxy primer and a polyurethane top coat.
The lower, milled ends of each door frame have provisions for the installation of the locking and latching mechanism. An access panel covers the lower part of the cargo door.
The outer skin has cutouts for the vent door and for the installation of the three hoisting lugs.
The attachment fittings of the door actuators are part of the door frames FR25A and FR26A.
For the attachment of the door seal, the related retainers are riveted at the edge members around the cargo doors.
On the inner skin there are provisions to attach the door lining with quick-release fasteners.
In the corners of the door beams and door frames, there are gaps to drain condensed water. Two drain valves are installed on the lowest beam of the pressure-tight structure and drain this water via drain hoses to the outside. Some drain holes are added in the critical areas of the internal structure which is painted with a water repellent agent.
Additional access cover are in the outer skin of the cargo door to get access to the drift pin assembly from the outer side.
The primary structure has vertical and horizontal edge members, fairings, longitudinal beams, frames, and an inner and outer skin. These formed and milled components are made from aluminum alloy and are riveted together with a sealant compound to make a corrosion-resistant cargo door. The sealant compound between the skin and the edge members makes sure that the primary structure is pressure-tight.
To prevent corrosion, all components have a surface protection of chromic acid anodizing plus epoxy primer and a polyurethane top coat.
The lower, milled ends of each door frame have provisions for the installation of the locking and latching mechanism. An access panel covers the lower part of the cargo door.
The outer skin has cutouts for the vent door and for the installation of the three hoisting lugs.
The attachment fittings of the door actuators are part of the door frames FR25A and FR26A.
For the attachment of the door seal, the related retainers are riveted at the edge members around the cargo doors.
On the inner skin there are provisions to attach the door lining with quick-release fasteners.
In the corners of the door beams and door frames, there are gaps to drain condensed water. Two drain valves are installed on the lowest beam of the pressure-tight structure and drain this water via drain hoses to the outside. Some drain holes are added in the critical areas of the internal structure which is painted with a water repellent agent.
Additional access cover are in the outer skin of the cargo door to get access to the drift pin assembly from the outer side.
B. Door Suspension
The connection of the cargo door to the fuselage includes the two halves of the piano hinges and two hinge pins. The outer parts of the multi-section piano hinges are made of titanium alloy and the mid parts are made of aluminum alloy. One halve of the piano hinges is attached to the upper edge member of the cargo door with screws. The related, opposite piano hinge halves are riveted on the upper door frame fitting of the fuselage.
The hinge pins connect the door and the fuselage hinges. The fairings at both ends of the piano hinges hold and safety the hinge pins in their positions.
The connection of the cargo door to the fuselage includes the two halves of the piano hinges and two hinge pins. The outer parts of the multi-section piano hinges are made of titanium alloy and the mid parts are made of aluminum alloy. One halve of the piano hinges is attached to the upper edge member of the cargo door with screws. The related, opposite piano hinge halves are riveted on the upper door frame fitting of the fuselage.
The hinge pins connect the door and the fuselage hinges. The fairings at both ends of the piano hinges hold and safety the hinge pins in their positions.
C. Lining and Insulation
To protect the cargo door against fire, a door lining is installed on the inner skin with quick-release fasteners and VELCRO tapes. This lining is in one section and made of prepreg layers. To protect the cargo door against heat and sound, a self-adhesive insulation mat is attached to the door lining. The mat is made of polyethylene foam.
To protect the cargo door against fire, a door lining is installed on the inner skin with quick-release fasteners and VELCRO tapes. This lining is in one section and made of prepreg layers. To protect the cargo door against heat and sound, a self-adhesive insulation mat is attached to the door lining. The mat is made of polyethylene foam.
D. Proximity Switches
The proximity switches of the cargo door include a target and a sensor and have a separated electronic system.
The proximity switch 28WV monitors the position of the door handle. The sensor is attached via a bracket at beam 4 near FR27 and the target is installed on the forward edge the door handle.
The proximity switch 30WV monitors the position of the cargo door. The sensor is installed in the door sill area near FR25 and the target is attached on the target lever (part of the switch mechanism).
These two proximity switches send information to the ECAM system when the cargo door is closed or opened (Ref. AMM D/O 52-71-00-00).
The proximity switch 5MJ is included in the door control system (Ref. 52-35-00). The sensor is installed on the beam 4 near frame FR25A and the target is installed on the control lever of the latching shaft. This switch prevents the hydraulic operation of the cargo door if both parts are not in line.
The proximity switches of the cargo door include a target and a sensor and have a separated electronic system.
The proximity switch 28WV monitors the position of the door handle. The sensor is attached via a bracket at beam 4 near FR27 and the target is installed on the forward edge the door handle.
The proximity switch 30WV monitors the position of the cargo door. The sensor is installed in the door sill area near FR25 and the target is attached on the target lever (part of the switch mechanism).
These two proximity switches send information to the ECAM system when the cargo door is closed or opened (Ref. AMM D/O 52-71-00-00).
The proximity switch 5MJ is included in the door control system (Ref. 52-35-00). The sensor is installed on the beam 4 near frame FR25A and the target is installed on the control lever of the latching shaft. This switch prevents the hydraulic operation of the cargo door if both parts are not in line.
E. Door Seal
The door seal made of silicone rubber integrated with fabric is a round hose-type seal with inflation holes. The door seal is installed in the retainers so that the inflation holes show to the inner side of the cargo compartment.
When the cargo door is in the closed position, the door seal comes into contact with the fuselage profile. Due to the higher internal pressure of the cargo compartment during the flight, the door seal is inflated via the inflation holes so that the cargo compartment is sealed air-tight.
The door seal made of silicone rubber integrated with fabric is a round hose-type seal with inflation holes. The door seal is installed in the retainers so that the inflation holes show to the inner side of the cargo compartment.
When the cargo door is in the closed position, the door seal comes into contact with the fuselage profile. Due to the higher internal pressure of the cargo compartment during the flight, the door seal is inflated via the inflation holes so that the cargo compartment is sealed air-tight.
F. Cargo Door Mechanism
The cargo door mechanism includes the subsequent components:
The cargo door mechanism includes the subsequent components:
- the door handle mechanism with the handle flap
- the latching mechanism with the interlock mechanism,
- the locking mechanism with the vent door and related mechanism,
- the drift pin mechanism,
- the switch mechanism.
- The door handle mechanism with the handle flap
- The latching mechanism with the interlock mechanism
- The locking mechanism with the vent door and the related mechanism
- The switch mechanism.
(1) Door Handle Mechanism
The door handle mechanism is installed between FR27 and FR27A to latch/unlatch and lock/unlock the cargo door.
Parts of the door handle mechanism are the door handle, the Maltese-cross assembly, the linkage mechanism and the handle spring.
The door handle mechanism operates the locking mechanism when the the door handle is pulled up to the 65 degree position. When the door handle is lifted to the 128 degree position, the door handle mechanism operates the latching mechanism.
The Maltese-cross assembly transmit the different movement sequence steps of the door handle as follows:
The gas spring assembly makes sure that the linkage mechanism stays in a overcenter position when the door handle is in the 65 degree position.
The handle spring keeps the door handle in its fully lifted position and vice versa when the door handle is moved into its recess.
In this position the target at the door handle operates the proximity sensor 28WV at beam 4.
The door handle mechanism is installed between FR27 and FR27A to latch/unlatch and lock/unlock the cargo door.
Parts of the door handle mechanism are the door handle, the Maltese-cross assembly, the linkage mechanism and the handle spring.
The door handle mechanism operates the locking mechanism when the the door handle is pulled up to the 65 degree position. When the door handle is lifted to the 128 degree position, the door handle mechanism operates the latching mechanism.
The Maltese-cross assembly transmit the different movement sequence steps of the door handle as follows:
- the Maltese-cross lock operates the locking shaft via the linkage mechanism,
- the Maltese-cross latch operates the latching shaft via the connection rod.
The gas spring assembly makes sure that the linkage mechanism stays in a overcenter position when the door handle is in the 65 degree position.
The handle spring keeps the door handle in its fully lifted position and vice versa when the door handle is moved into its recess.
In this position the target at the door handle operates the proximity sensor 28WV at beam 4.
(2) Door Handle Mechanism
The door handle mechanism is installed between FR27 and FR27A to latch/unlatch and lock/unlock the cargo door.
The door handle mechanism includes the door handle, the Maltese-cross assembly, the linkage mechanism and the handle spring.
The door handle mechanism operates the locking mechanism when the the door handle is lifted to the 65 degrees position. When the door handle is lifted to the 128 degrees position, the door handle mechanism operates the latching mechanism.
The Maltese-cross assembly transmits the different movement sequence steps of the door handle as follows:
The gas spring assembly makes sure that the linkage mechanism stays in an overcenter position when the door handle is in the 65 degrees position.
The handle spring keeps the door handle in its fully lifted position and fully closed when the door handle is moved into its recess.
In this position the target at the door handle operates the proximity sensor 28WV at beam 4.
The door handle includes the spring-loaded handle flap, the push-button and the linkage with the catch hook. The inboard movement of the handle flap operates the linkage to disengage the hook from the locking handle. The hook safeties the door handle when it is pushed into its recess.
The push-button is a safety device installed on the door handle immediately above the handle flap. It must be pushed in and held before the operation of the handle flap. This prevents accidental operation of the handle flap which can cause the door to open.
The door handle mechanism is installed between FR27 and FR27A to latch/unlatch and lock/unlock the cargo door.
The door handle mechanism includes the door handle, the Maltese-cross assembly, the linkage mechanism and the handle spring.
The door handle mechanism operates the locking mechanism when the the door handle is lifted to the 65 degrees position. When the door handle is lifted to the 128 degrees position, the door handle mechanism operates the latching mechanism.
The Maltese-cross assembly transmits the different movement sequence steps of the door handle as follows:
- The Maltese-cross lock operates the locking shaft through the linkage mechanism
- The Maltese-cross latch operates the latching shaft through the connection rod.
The gas spring assembly makes sure that the linkage mechanism stays in an overcenter position when the door handle is in the 65 degrees position.
The handle spring keeps the door handle in its fully lifted position and fully closed when the door handle is moved into its recess.
In this position the target at the door handle operates the proximity sensor 28WV at beam 4.
The door handle includes the spring-loaded handle flap, the push-button and the linkage with the catch hook. The inboard movement of the handle flap operates the linkage to disengage the hook from the locking handle. The hook safeties the door handle when it is pushed into its recess.
The push-button is a safety device installed on the door handle immediately above the handle flap. It must be pushed in and held before the operation of the handle flap. This prevents accidental operation of the handle flap which can cause the door to open.
(3) Latching Mechanism with Interlock Mechanism
The latching mechanism which is installed in the lower part of the cargo door includes the subsequent components:
The Maltese-cross latch transmits the movement of the door handle (from 65 degree to 128 degree) via the connection rod to the latching shaft. The shaft levers then operate the latching units which move their latching hooks into the latched or released position.
The interlock mechanism prevents the operation of the door handle when the cargo door is still opened. The spring unit moves the interlock lever to the blocked position so that its stop bolt touches the interlock cam.
The latching mechanism which is installed in the lower part of the cargo door includes the subsequent components:
- the latching shaft which has six shaft levers, the control lever, the interlock cam and the link lever,
- the six latching units which have a latching hook, a bellcrank, a bellcrank lever and a connection rod,
- the interlock mechanism which includes the interlock lever with the stop bolt, the connection rod and the spring unit.
The Maltese-cross latch transmits the movement of the door handle (from 65 degree to 128 degree) via the connection rod to the latching shaft. The shaft levers then operate the latching units which move their latching hooks into the latched or released position.
The interlock mechanism prevents the operation of the door handle when the cargo door is still opened. The spring unit moves the interlock lever to the blocked position so that its stop bolt touches the interlock cam.
(4) Latching Mechanism with Interlock Mechanism
The latching mechanism which is installed in the lower part of the cargo door includes the subsequent components:
The Maltese-cross latch transmits the movement of the door handle (from 65 degree to 128 degree) through the connection rod to the latching shaft. The shaft levers then operate the latching units which move their latching hooks into the latched or released position.
The interlock mechanism prevents the operation of the door handle when the cargo door stays open. The spring unit moves the interlock lever to the blocked position to let the stop bolt touch the interlock cam.
The latching mechanism which is installed in the lower part of the cargo door includes the subsequent components:
- The latching shaft which has six shaft levers, the control lever, the interlock cam and the link lever
- The six latching units which have a latching hook, a bellcrank, a bellcrank lever and a connection rod
- The interlock mechanism which includes the interlock lever with the stop bolt, the roller and the spring unit.
The Maltese-cross latch transmits the movement of the door handle (from 65 degree to 128 degree) through the connection rod to the latching shaft. The shaft levers then operate the latching units which move their latching hooks into the latched or released position.
The interlock mechanism prevents the operation of the door handle when the cargo door stays open. The spring unit moves the interlock lever to the blocked position to let the stop bolt touch the interlock cam.
(5) Locking Mechanism with Vent Door Mechanism
The locking mechanism is installed parallel to and below the latching mechanism in the lower part of the cargo door. The primary task of this mechanism is to tell the operator that the latching mechanism is correctly latched.
The locking mechanism includes the subsequent components:
The control rod transmits the movement of the door handle (from 0 degree to 65 degree ) through the Maltese-cross lock to the locking shaft. The lock cams then engage with, or disengage from, the recess of the latching hooks. The engaged lock cams prevent the operation of the latching hooks. Then, the operator can see the green mark on each lock cam through the indication windows of the access panel. When the operator can see a red mark in the indication windows, then the cam locks are disengaged from the latching hooks.
A connection rod transmits the movement of the locking shaft to the drive shaft of the gear box. The output shaft of the gear box operates the drawbar which opens or closes the vent door.
The locking mechanism is installed parallel to and below the latching mechanism in the lower part of the cargo door. The primary task of this mechanism is to tell the operator that the latching mechanism is correctly latched.
The locking mechanism includes the subsequent components:
- the locking shaft which has a link rod, six lock cams with a red and green mark, a drift pin lever and a vent door lever,
- the vent door mechanism which opens and closes the vent door,
- the linkage mechanism which includes the control rod and the gas spring.
The control rod transmits the movement of the door handle (from 0 degree to 65 degree ) through the Maltese-cross lock to the locking shaft. The lock cams then engage with, or disengage from, the recess of the latching hooks. The engaged lock cams prevent the operation of the latching hooks. Then, the operator can see the green mark on each lock cam through the indication windows of the access panel. When the operator can see a red mark in the indication windows, then the cam locks are disengaged from the latching hooks.
A connection rod transmits the movement of the locking shaft to the drive shaft of the gear box. The output shaft of the gear box operates the drawbar which opens or closes the vent door.
(6) Locking Mechanism
The locking mechanism is installed parallel to and below the latching mechanism in the lower part of the cargo door. The primary task of this mechanism is to tell the operator that the latching mechanism is correctly latched.
The locking mechanism includes the subsequent components:
The control rod transmits the movement of the door handle (from 0 degrees to 65 degrees) through the maltese-cross lock to the locking shaft. The lock cams then engage with, or disengage from, the recess of the latching hooks. The engaged lock cams prevent the operation of the latching hooks. Then, the operator can see the green mark on each safety cam through the indication windows of the access panel. When the operator can see a red mark in the indication windows, then the lock cams are disengaged from the latching hook.
The vent door lever transmits the movement of the locking shaft through the sequence shaft to the input bellcrank. The connection rod operates the linkage of the drift pins and the vent door.
The locking mechanism is installed parallel to and below the latching mechanism in the lower part of the cargo door. The primary task of this mechanism is to tell the operator that the latching mechanism is correctly latched.
The locking mechanism includes the subsequent components:
- the locking shaft, which has a link rod, six lock cams with a red and green mark, a vent door lever, a connection rod and a sequence shaft.
- the linkage mechanism which includes the control rod, the serrated shaft and the gas spring.
The control rod transmits the movement of the door handle (from 0 degrees to 65 degrees) through the maltese-cross lock to the locking shaft. The lock cams then engage with, or disengage from, the recess of the latching hooks. The engaged lock cams prevent the operation of the latching hooks. Then, the operator can see the green mark on each safety cam through the indication windows of the access panel. When the operator can see a red mark in the indication windows, then the lock cams are disengaged from the latching hook.
The vent door lever transmits the movement of the locking shaft through the sequence shaft to the input bellcrank. The connection rod operates the linkage of the drift pins and the vent door.
(7) Drift Pin Mechanism
The drift pin mechanism is installed in the middle of the cargo door. It decreases the contour off-set between the fuselage and the door. The drift pin mechanism has a drift pin assy and the linkages mechanism, which includes the connection rods, the control rods, the bearing assy and the housing assy.
The linkage mechanism transmit the movement of the locking shaft to the drift pins which retract or extent then. When the cargo door is correctly locked, the extended drift pins engage with the pockets of the fuselage frame.
The drift pin mechanism is installed in the middle of the cargo door. It decreases the contour off-set between the fuselage and the door. The drift pin mechanism has a drift pin assy and the linkages mechanism, which includes the connection rods, the control rods, the bearing assy and the housing assy.
The linkage mechanism transmit the movement of the locking shaft to the drift pins which retract or extent then. When the cargo door is correctly locked, the extended drift pins engage with the pockets of the fuselage frame.
(8) Drift Pin Mechanism with Vent Door Mechanism
The drift pin mechanism is installed in the middle of the cargo door. It decreases the contour off-set between the fuselage and the door. The drift pin mechanism has a drift pin assy and a linkage mechanism which includes the connection rods, the control rods, the drift pin bellcrank and the input bellcrank.
The linkage mechanism transmits the movement of the locking shaft to the drift pins which retract or extend them. When the cargo door is correctly locked, the extended drift pins engage with the pockets of the fuselage frame.
The vent door mechanism causes the vent door to open or close in accordance to the position of the drift pins.
The drift pin mechanism is installed in the middle of the cargo door. It decreases the contour off-set between the fuselage and the door. The drift pin mechanism has a drift pin assy and a linkage mechanism which includes the connection rods, the control rods, the drift pin bellcrank and the input bellcrank.
The linkage mechanism transmits the movement of the locking shaft to the drift pins which retract or extend them. When the cargo door is correctly locked, the extended drift pins engage with the pockets of the fuselage frame.
The vent door mechanism causes the vent door to open or close in accordance to the position of the drift pins.
(9) Switch Mechanism
The switch mechanism is installed in the lower part of the cargo doors at FR25. This mechanism includes the target lever with the related target and the link assy.
The target lever is attached on the support fitting which is riveted on the frame structure. The upper fork end of the link assy is installed on the lever of the drive shaft and its lower fork end on the target lever.
The link assy transmits the movement of the drive shaft to the target lever. The target moves to or away from the proximity sensor 30WV which is installed below the door sill of the fuselage.
The switch mechanism is installed in the lower part of the cargo doors at FR25. This mechanism includes the target lever with the related target and the link assy.
The target lever is attached on the support fitting which is riveted on the frame structure. The upper fork end of the link assy is installed on the lever of the drive shaft and its lower fork end on the target lever.
The link assy transmits the movement of the drive shaft to the target lever. The target moves to or away from the proximity sensor 30WV which is installed below the door sill of the fuselage.
5. Operation
Function of Latching and Locking Mechanism ** ON A/C NOT FOR ALL
Function of Latching and Locking Mechanism ** ON A/C NOT FOR ALL
Function of Interlock Mechanism ** ON A/C NOT FOR ALL
Function of Interlock Mechanism ** ON A/C NOT FOR ALL
Function of Latching and Locking Mechanism ** ON A/C NOT FOR ALL Function of Latching and Locking Mechanism ** ON A/C NOT FOR ALL Function of Interlock Mechanism ** ON A/C NOT FOR ALL Function of Interlock Mechanism ** ON A/C NOT FOR ALL A. Release Mode
To release the cargo door mechanism, pull the door handle away from the cargo door. To get access to the door handle, the operator pushes the spring-loaded handle flap automatically inboard. This releases the door handle from the catch hook of the door structure.
When the door handle is pulled up to the 65 degree position, the subsequent occurs:
To release the cargo door mechanism, pull the door handle away from the cargo door. To get access to the door handle, the operator pushes the spring-loaded handle flap automatically inboard. This releases the door handle from the catch hook of the door structure.
When the door handle is pulled up to the 65 degree position, the subsequent occurs:
To release the cargo door mechanism, pull the door handle away from the cargo door. To get access to the door handle, the operator pushes and holds the push-button and then pushes the spring-loaded handle flap inboard. This releases the door handle from the catch hook of the door structure.
When the door handle is lifted to the 65 degrees position, the subsequent occurs:
To disengage the latching hooks from their fuselage fittings, lift the door handle up to the 128 degree position. During this movement, the subsequent occurs:
When the cargo door opens, the roller lever of the interlock mechanism moves away from the interlock fitting of the door sill. The spring unit extends and moves the interlock lever so that its stop bolt touches the interlock cam. This causes the interlock mechanism to block the operation of the door handle which is in the UNLATCHED position.
To disengage the latching hooks from their fuselage fittings, you can lift the door handle up to the 128 degree position. During this movement, the subsequent occurs:
When the cargo door opens, the roller of the interlock mechanism moves away from the interlock fitting of the door sill. The spring unit extends and moves the interlock lever to let the stop bolt touch the interlock cam. The interlock mechanism thus causes a blockage to the door handle which is in the UNLATCHED position.
To release the cargo door mechanism, pull the door handle away from the cargo door. To get access to the door handle, the operator pushes the spring-loaded handle flap automatically inboard. This releases the door handle from the catch hook of the door structure.
When the door handle is pulled up to the 65 degree position, the subsequent occurs:
- the door handle engages with the Maltese-cross lock to operate the linkage mechanism. Its control rod then turns the locking shaft so that the lock cams move away from the recess of the latching hooks,
- the drift pin lever moves up and operates the linkage mechanism. The control rods transmit the movement through the housing assy and the bearing assy to the connection rods. They move the drift pins which retract from the pockets of the fuselage frames.
- the vent door lever operates the connection rod which turns the drive shaft of the gear box. The output shaft of the gear box also turns and moves the drawbar which opens the vent door. The drive shaft operates the link assy at the same time so that the target lever moves away from the door sill. The related target does not operate the proximity switch 30WV (Ref. AMM D/O 52-71-00-00).
To release the cargo door mechanism, pull the door handle away from the cargo door. To get access to the door handle, the operator pushes the spring-loaded handle flap automatically inboard. This releases the door handle from the catch hook of the door structure.
When the door handle is pulled up to the 65 degree position, the subsequent occurs:
- the door handle engages with the maltese-cross lock to operate the linkage mechanism. Its control rod then turns the locking shaft so that the lock cams move away from the recess of the latching hooks.
- the drift pin lever moves up and operates the linkage mechanism. The control rods transmit the movement through the housing assy and the bearing assy to the connection rods. They move the drift pins which retract from the pockets of the fuselage frames, at the same time the vent door mechanism causes the vent door to open.
- The drive shaft operates the link assy at the same time so that the target lever moves away from the door sill. The related target does not operate the proximity switch 32WV (Ref. AMM D/O 52-71-00-00).
To release the cargo door mechanism, pull the door handle away from the cargo door. To get access to the door handle, the operator pushes and holds the push-button and then pushes the spring-loaded handle flap inboard. This releases the door handle from the catch hook of the door structure.
When the door handle is lifted to the 65 degrees position, the subsequent occurs:
- The door handle engages with the Maltese-cross lock to operate the linkage mechanism. Its control rod then turns the locking shaft until the lock cams move away from the latching hooks
- The drift pin lever moves up and operates the linkage mechanism. The control rods transmits the movement through the housing assembly and the bearing assembly to the connection rods. They move the drift pins which retract from the pockets of the fuselage frames, at the same time the vent door mechanism causes the vent door to open
- The drive shaft operates the link assembly at the same time until the target lever moves away from the door sill. The related target does not operate the proximity switch 32WV (Ref. AMM D/O 52-71-00-00).
To disengage the latching hooks from their fuselage fittings, lift the door handle up to the 128 degree position. During this movement, the subsequent occurs:
- the door handle disengages from the Maltese-cross lock and engages with the Maltese-cross latch. This causes the latching shaft to turn in the release direction.
- the shaft levers operate the bellcranks which move the bellcrank levers so that the latching hooks disengage from the eccentric bolts of the fuselage fittings,
- the control lever moves the target to the proximity sensor 5MJ which sends a signal to the door control circuit (Ref. AMM D/O 52-35-00-00),
- the interlock cam moves up so that the released interlock mechanism is serviceable.
When the cargo door opens, the roller lever of the interlock mechanism moves away from the interlock fitting of the door sill. The spring unit extends and moves the interlock lever so that its stop bolt touches the interlock cam. This causes the interlock mechanism to block the operation of the door handle which is in the UNLATCHED position.
To disengage the latching hooks from their fuselage fittings, you can lift the door handle up to the 128 degree position. During this movement, the subsequent occurs:
- The door handle disengages from the Maltese-cross lock and engages with the Maltese-cross latch. This causes the latching shaft to turn in the release direction.
- The shaft levers operate the bellcranks which move the bellcrank levers to let the latching hooks disengage from the eccentric bolts of the fuselage fittings.
- The control lever moves the target to the proximity sensor 5MJ which sends a signal to the door control circuit (Ref. AMM D/O 52-35-00-00).
- The interlock cam moves up to make the released interlock mechanism serviceable.
When the cargo door opens, the roller of the interlock mechanism moves away from the interlock fitting of the door sill. The spring unit extends and moves the interlock lever to let the stop bolt touch the interlock cam. The interlock mechanism thus causes a blockage to the door handle which is in the UNLATCHED position.
B. Locking Mode
When the cargo door closes, the roller lever of the interlock mechanism moves against the interlock fitting of the door sill. The roller lever then operates the connection rod which moves the interlock lever against the spring unit. If the cargo door is fully closed, the subsequent occurs:
To engage the latching hooks on their fuselage fittings, pull the door handle down to the 65 degree position. During this movement the subsequent occurs:
When the cargo door closes, the roller of the interlock mechanism moves against the interlock fitting of the door sill. The roller then moves the interlock lever against the spring unit. If the cargo door is fully closed, the subsequent occurs:
To engage the latching hooks on their fuselage fittings, you can pull the door handle down to the 65 degree position. During this movement the subsequent occurs:
When the door handle is moved down and pushed inboard so that it is in line with the cargo door contour, the subsequent occurs:
The drive shaft operates the link assy at the same time so that the target lever moves to the door sill. The related target operates the proximity switch 30WV (Ref. AMM D/O 52-71-00-00).
When the door handle is in line with the cargo door contour, the target operates the proximity switch 28WV . This causes the visual warning in the cockpit to go off (Ref. AMM D/O 52-71-00-00). In this position, the hook of the door structure safeties the door handle against movement.
When the door handle is moved down and pushed inboard so that it is in line with the cargo door contour, the subsequent occurs:
The sequence shaft operates the link assy at the same time so that the target lever moves to the door sill. The related target operates the proximity switch 32WV (Ref. AMM D/O 52-71-00-00).
When the door handle is in line with the cargo door contour, the target operates the proximity switch 34WV . This causes the visual warning in the cockpit to go off (Ref. AMM D/O 52-71-00-00). In this position, the hook of the door structure safeties the door handle against movement.
When the cargo door closes, the roller lever of the interlock mechanism moves against the interlock fitting of the door sill. The roller lever then operates the connection rod which moves the interlock lever against the spring unit. If the cargo door is fully closed, the subsequent occurs:
- the stop bolt of the interlock lever does not block the lock cam of the locking shaft,
- the door handle is serviceable to lock the closed cargo door.
To engage the latching hooks on their fuselage fittings, pull the door handle down to the 65 degree position. During this movement the subsequent occurs:
- the Maltese-cross latch operates the connection rod which turns the latching shaft in the latched position,
- the shaft levers operate the bellcranks which move the bellcrank levers. The latching hooks engage the eccentric bolt of the fuselage fitting.
- the control lever turns the related target away from the proximity sensor 5MJ to stop the hydraulic operation (Ref. AMM D/O 52-35-00-00),
- the interlock cam comes to its unblocked position.
When the cargo door closes, the roller of the interlock mechanism moves against the interlock fitting of the door sill. The roller then moves the interlock lever against the spring unit. If the cargo door is fully closed, the subsequent occurs:
- The stop bolt of the interlock lever does not cause a blockage to the lock cam of the locking shaft.
- The door handle is serviceable to lock the closed cargo door.
To engage the latching hooks on their fuselage fittings, you can pull the door handle down to the 65 degree position. During this movement the subsequent occurs:
- The Maltese-cross latch operates the connection rod which turns the latching shaft in the latched position.
- The shaft levers operate the bellcranks which move the bellcrank levers. The latching hooks engage the eccentric bolt of the fuselage fitting.
- The control lever turns the related target away from the proximity sensor 5MJ to stop the hydraulic operation (Ref. AMM D/O 52-35-00-00).
- The interlock cam comes away from its blocked position.
When the door handle is moved down and pushed inboard so that it is in line with the cargo door contour, the subsequent occurs:
- the door handle disengages from the Maltese-cross latch and engages with the Maltese-cross lock. This causes the control rod to operate and the latching shaft turns so that the lock cams move into the recess of the latching hooks.
- the handle spring keeps the door handle in the overcenter position,
- the drift pin lever moves down and operates the linkage mechanism. The vertical control rods transmit the movement via the housing assy and the bearing assy to the horizontal linkages. They move the drift pins which extends into the pockets of the fuselage frame.
- the vent door lever operates the connection rod which turns the drive shaft of the gear box. The output shaft turns and moves the draw bar which closes the vent door.
The drive shaft operates the link assy at the same time so that the target lever moves to the door sill. The related target operates the proximity switch 30WV (Ref. AMM D/O 52-71-00-00).
When the door handle is in line with the cargo door contour, the target operates the proximity switch 28WV . This causes the visual warning in the cockpit to go off (Ref. AMM D/O 52-71-00-00). In this position, the hook of the door structure safeties the door handle against movement.
When the door handle is moved down and pushed inboard so that it is in line with the cargo door contour, the subsequent occurs:
- the door handle disengages from the maltese-cross latch and engages with the Maltese-cross lock. This causes the control rod to operate and the latching shaft turns so that the safety cams move into the recess of the latching hooks.
- the handle spring keeps the door handle in the overcenter position.
- the vent door lever moves down and operates the connection rod. The sequence shaft transmits the movement through the input bellcrank and the drift pin bellcrank to the horizontal linkages. They move the drift pins which extend into the pockets of the fuselage frame.
- the vent door bellcrank operates the vent door rod which closes the vent door.
The sequence shaft operates the link assy at the same time so that the target lever moves to the door sill. The related target operates the proximity switch 32WV (Ref. AMM D/O 52-71-00-00).
When the door handle is in line with the cargo door contour, the target operates the proximity switch 34WV . This causes the visual warning in the cockpit to go off (Ref. AMM D/O 52-71-00-00). In this position, the hook of the door structure safeties the door handle against movement.