The passenger and crew entrance door is found on the left side of the forward fuselage between FS345.00 and FS375.00. The door gives access from the ground to the passenger and flight compartments and it is the primary exit from the aircraft.

The top step of the stairs is part of the passenger compartment, one step down from the general floor level. You can lift the door to the closed position manually or with electrical power. When closed, the door becomes an airtight plug to prevent the loss of pressurization in the fuselage.

The door is a semi-plug type with a built-in set of airstairs. The frames and skin are made of the same light alloy materials as the fuselage. There are some steel components in the latch mechanism and the airstair is made of composite materials. One handrail is installed on the aft side of the door. It is possible to close the door manually and electrically.

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The passenger door structure is made from skins, frames, beams and diaphragms assembled with fasteners in the same way as the fuselage structure. Five stop fittings are installed on each side of the door which engage with stop fittings attached to the door frame. A roller attached to each side of the door engages with a fitting guide at the top of the door frame. Equivalent rollers at the bottom of the door frame engage with fitting guides on the door. The stop fittings on the door have screws for the adjustment of the door position when fully closed. The rollers also have adjustable fittings.

The center area of the inside of the door has two machined mounting frames to attach the door latch mechanism. In the upper area of the door there is a vent flap which releases remaining cabin air pressure before the door latches can open. The flap has a flexible seal around the edge. At the bottom of the door there is an enclosure for the external handle. The passenger door structure attaches to a hinge mechanism through a system of links and rollers. The two hinge points connect to the fuselage with one bolt at each side of the fuselage step.

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The door latch mechanism has two cams which are part of a primary shaft installed horizontally on the door structure. The primary shaft turns with inputs from the internal handle and the external handle. The internal handle attaches directly to the primary shaft. The external handle connects to the primary shaft through control rods and a lever. The two cams move rollers in a specified sequence so that different actions occur at the correct times. An open-lock system locks the door when it is in the fully open position. The latch mechanism has three different primary functions, as follows:

Vent Flap Function

When the vent flap cam turns, force is applied through a roller to a control rod. One more control rod transmits the force to the vent flap through a link. In normal conditions, three springs cause the vent flap to open when the control rod releases the force. The vent flap moves directly away from the opening in the outer surface of the door. In icing conditions, the mechanism causes the vent flap to move parallel to the outer surface of the door. After the ice is broken, the three springs open the vent flap.

It is not possible to open the door if there is some remaining cabin pressure. A pressure lock lever, which connects to the vent flap through a control rod and a link, prevents movement of the inner handle and the vent flap stays closed. After the cabin pressure is released, the springs cause the vent flap to open, the pressure lock disengages, and the door handles can then operate. The springs also make sure that the vent flap opens if a part of the operating mechanism becomes unserviceable or disconnects. If one spring breaks, the other two springs can open the vent flap to release cabin air pressure.

Door Lifting Function

The other cam on the primary shaft of the latch mechanism causes the door to move vertically. As this cam turns, force is applied to a lever which connects to a lifting shaft installed parallel to the primary shaft. At each end of the lifting shaft is a lever which connects to the door hinge mechanism. Movement of the two levers causes the door to move vertically in relation to the hinge.

The lifting shaft has a locking pawl connected to the vent flap cam which stops vertical movement of the door unless the vent flap is fully open. A pressure lock system also stops more movement of the primary cam shaft if the vent flap is kept closed by too much cabin pressure. When the pressure decreases sufficiently, the springs can open the vent flap and the locking pawl moves to let the lifting shaft turn.

Open-Lock Function

When the door is fully open it is not possible to close it until you release a system of mechanical locks. This lock mechanism also prevents too much vertical movement of the steps as personnel go into and out of the aircraft. The lock system has a locking pawl which is integral with the external handle pivot shaft. A locking hook is attached to the shaft of a spring-loaded lever installed on the aft face of the door structure. Two other hooks are also installed behind the riser of the top step, which is part of the door hinge structure. These hooks connect to the primary locking hook through a lever and a control rod.

When the door is fully open, the primary lock engages the locking pawl on the external handle pivot shaft. The hinge-lock hooks also engage pins on the hinge structure to keep the door rigid in that position. To close the door it is first necessary to operate the open-lock lever to release all the locking hooks. As the door closes, the lever touches a roller on the door frame which keeps the primary locking hook away from the locking pawl. In this position, the hinge locking hooks are also kept away from their locking pins.

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The internal handle of the door is found on the forward face of the airstairs and attaches to the primary shaft of the door latch mechanism. There is a red nylon knob at 90 degrees to the handle for easy use during operation. An EXIT/PULL placard is attached to the handle. The primary shaft has two adjustable stop bolts which set the limits to the angular range of movement of the handle. A cover is installed over the pivot point area of the handle, attached with screws to the side of the airstairs.

A system of links connected to the locking hook on the primary shaft moves a green flag indicator when the door starts to unlock. The flag shows through a small window in the handle cover to give passengers and crew a visual indication of the position of the latch mechanism when the door is closed. Unless the door is fully locked, the window shows a red warning indication.

A telescopic spring strut keeps the primary cam shaft in tension as the internal handle moves. Two spring-loaded detents are installed in the latch mechanism. One is adjacent to the external handle pivot shaft and the other is adjacent to the primary shaft. These detents let the operator feel the correct position of the mechanism. They put a load on the handle at the start and at the end of the mechanism cycle and they also prevent unwanted operation of the door.

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Passengers or crew can close the door electrically from inside the aircraft. A switch on the left equipment rack controls an electrical actuator which winds a wire cable attached to the door.

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Personnel can use an external handle to open and close the door from the ground. The door can be locked after the installation of a lock cylinder in this handle. The handle has a spring-loaded finger flap to make it easy to pull the handle out of its recess in the door. A plastic stop is installed inside the door handle recess. This is adjustable to make sure that the external handle is flush with the outer skin of the door when the door is closed.

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A small access panel with a quick-release fastener is found in the fuselage near the forward, bottom corner of the passenger door. The door external switch is inside this panel. Operation of the switch from the ground makes the door close with the aid of an electrical actuator.

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The door actuator is an electric motor which can also operate like an inertia reel. It is installed in the floor structure at the aft, bottom corner of the fuselage door frame. The passenger door actuator gets power when the aircraft is powered or the passenger door switch (internal or external) is activated. The usual operation of the actuator is with the passenger door internal or external switch. An emergency handle and cable attached to a pulley on the actuator helps passengers or crew lift the door if no power is available.

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A wire cable from the actuator goes over a pulley near the top of the airstair handrail and connects to a point on the aft side of the door. No electrical power is necessary when the door opens, because the weight of the door helps the door open quickly at first. When the door is almost fully open, the inertia reel function causes the door to open more slowly. If the door internal or external switch is operated, the actuator lifts the door with the cable and moves it to the closed position.

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A single handrail, made in two parts with a hinge at the joint, is installed on the aft side of the door. The top handrail support arm connects to the fuselage structure inside the door frame. The pulley for the door actuator cable is installed between the two sides of the support arm. The bottom connection of the handrail is adjacent to the point where the actuator cable attaches. A rounded nylon fitting is attached to the side of the airstairs at the positions where the handrail stops when the door is fully open and fully closed.

When the door is fully open, one part of the handrail is parallel to the airstairs and the other is at 90° to it. As the door closes, the handrail folds at the hinge point. The nylon fittings stop unwanted movement of the handrails.

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The fuselage has a blade-type, silicone rubber and fabric seal installed in a channel around the door frame. The seal is made in many different parts to make sure that cabin air pressure does not decrease quickly if one part of the seal becomes unserviceable. The seal also keeps water out of the fuselage if a ditching occurs. As the door moves up into the closed position, the flexible pressure seal touches the edge of the door structure to make it airtight.

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The airstair is made from light composite materials and it can be removed quickly as one component to do maintenance on the door latch mechanism. Quick-release fasteners attach the airstair to the sides of the door frame. Two of the step risers have access panels in them. There are four steps in the airstair, with two other steps which are part of the door structure. On the aft face of the airstair there is a light-alloy cylinder with a quick-release cover where you can stow the ground lockpins. A light emitting diode (LED) light is installed in each riser to give lighting on the steps at night. These lights are a part of the entrance-area lighting.

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Two telescopic struts are installed on the passenger door, each with three concentric pistons. Each strut is connected at the bottom to the side of the door, and at the top to the fuselage door frame. The struts are used as dampers to make sure that the door does not open too quickly if the actuator cable breaks. They also transmit all personnel loads on the door into the fuselage structure.

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To unlock the door with the external handle, first push with your fingers on the handle flap. Hold the handle and pull it clear of the recess in the door. As you pull the handle up through approximately 110 degrees of movement, the vent flap opens and the door unlocks and lifts clear of the stop fittings. The door will then fall to the open position with the aid of gravity only. The telescopic struts and the door actuator cable make the door open slowly. To unlock the door from inside the aircraft, you must pull the internal handle up through approximately 100 degrees of movement. This has the same effect as the external handle and the door opens by gravity.

To close the door from the ground, you must first open the external door-switch access panel just forward of the door. When you set the switch to the closed position, the door actuator operates and lifts the door into the opening. After the door is fully lifted, you pull down on the external handle. At this time, the rollers go into the fitting guides, the door stop fittings align with the stop fittings on the frame, and the vent flap closes. The last step is to stow the external handle flush with the door outer surface.

To close the door from inside the passenger compartment, you must first operate the door internal switch on the bulkhead adjacent to the door. The door actuator lifts the door into position in the door frame and the last step is to push down on the internal handle. This causes the door to engage the rollers and stop fittings, and the vent flap closes.

To close the door if you operate the internal or the external switch, the actuator lifts the door with the cable and moves it to the closed position. To prevent injury to the passengers and crew, the ECU decreases the voltage when the door is almost in the fully closed position (21 to 14 degree door angle). This causes the door to close more slowly at the rate of 5 degrees ±3 degree door angle per second.

If no power is available, or cable is disengaged from the door, the door can be closed manually from outside the aircraft. With the help of two persons lift the door manually to its full closed position. Push the external door handle into the recess in the door and stow the external door handle flush with the passenger door outer surface.

If no power is available, or the actuator motor becomes unserviceable, the door can be lifted to the closed position from inside the aircraft. This is done with the aid of a handle on a short cable which winds on to the internal pulley of the door actuator. You must operate the manual cable a number of times until the door can be pulled into the closed position.

The table which follows gives the positions of the door as the internal handle moves through its full range of movement:

DEGREES OF MOVEMENT OF THE INTERNAL HANDLE	STEPS IN SEQUENCE
0°	Door closed and locked
5°	Vent flap starts to open
7°	Internal and external handle detents at top-dead-center (TDC)
12°	Pressure lock clear of locking pawl
15°	External handle proximity sensor target far
16°	Secondary lock disengages
22.5°	Primary lock proximity sensor far
23°	Vent flap open 40°, visual indicator shows red
25°	Primary lock clear of pawl
27°	Lifting shaft starts to turn, vent flap movement stops
50°	Primary spring pot at TDC
88°	Main shaft detent at TDC
93°	Outer handle detent at TDC
97°	Door lifting complete
100°	Primary shaft stop engaged

The passenger door is monitored by three different proximity sensors which supply signals used to give visual/sound indications to the flight crew.

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Component Location Index
IDENT	DESCRIPTION	LOCATION	IPC REF
-	PASSENGER DOOR	ZONE(S) 832	52-11-01
-	PASSENGER-DOOR LATCH MECHANISM	ZONE(S) 832	52-11-05
-	PASSENGER-DOOR INTERNAL HANDLE	ZONE(S) 832	52-11-09
-	PASSENGER-DOOR INTERNAL SWITCH	ZONE(S) 221	52-11-13
-	PASSENGER-DOOR EXTERNAL HANDLE	ZONE(S) 832	52-11-17
-	PASSENGER-DOOR EXTERNAL SWITCH	ZONE(S) 221AL	52-11-21
-	PASSENGER DOOR ACTUATOR	ZONE(S) 141	52-11-25
-	PASSENGER DOOR HANDRAIL	ZONE(S) 832	52-11-27
-	PASSENGER DOOR SEAL	ZONE(S) 141, 221	52-11-29
-	PASSENGER DOOR AIRSTAIR	ZONE(S) 832	52-11-31
-	PASSENGER DOOR TELESCOPIC STRUT	ZONE(S) 221	52-11-41

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