The service doors and panels allow accessibility to the various systems and components that require servicing and/or inspection.

The aft equipment-compartment door is sufficiently large to let ground personnel go into the rear fuselage to do maintenance. All other doors give access to components when open but personnel do not go into the openings. The doors have latches which are easy to operate with your hand and tools are not necessary. Doors and panels in aerodynamic fairings are made of composite materials. Doors which give access directly into the aircraft metal structure are made of light alloy.

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The aft equipment-compartment door is found under the rear fuselage of the aircraft between FS724.00 and FS759.00. The door is in the wing-to-fuselage fairing and personnel can get into the aft equipment compartment through this door. The dimensions of the door are approximately 26 by 34 in (66 by 86 cm).

The structure of the door has an outer and an inner skin made from graphite material, with a Nomex core between the skins. It is attached to the wing-to-fuselage fairing support-structure with two light alloy hinges. There is a latch which has a center housing and contains the operating handle. The latch connects to a shaft through a spring-loaded device. This shaft has a roller arm at each end. The rollers touch two stop fittings on the door surround structure when the door is closed.

To open the aft equipment-compartment door, if the door has a key lock (optional), it must be unlocked first. Then you must press a trigger plate on the outer skin. This releases the handle and, as you pull down on the handle, the door opens. To close the door you lift it into position then push the handle into its housing until it latches under the trigger plate. You get a visual indication that the door is locked when the handle is flush with the outer skin in its recess.

Note: 
The door has a strut which has a hinge at one end and has a lock mechanism at its other end. The strut is usually stowed in the door with the lock mechanism held in a clip. To lock the door in the open position, the lock mechanism can be engaged in a slot hole in a bracket on the fairing.

Aft Equipment-Compartment-Door Latch-Mechanism

The aft equipment-compartment door is held in the closed position with a pressure sensitive latch-mechanism at the aft edge. The function of the pressure sensitive latch-mechanism is to give protection to the primary structure of the aircraft if the passenger-compartment rear pressure-bulkhead breaks. The latch mechanism is sensitive to changes in pressure in the aft equipment compartment. It will unlatch and release the door if too much positive pressure is applied on the inner face of the door.

If the pressure on the door increases, a load is felt on the two roller arms. This load will push on the stop fittings on the door surround structure. The spring-device pushes back against this load. When sufficient pressure is felt on the inner door the spring device will compress. This will cause the roller arms move away from the stop fittings and the door will open.

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The tail-cone has two access panels that can be removed which give access to the auxiliary power unit (APU) for inspection and servicing.

Auxiliary Power Unit (APU) Access Panel (320AB)

The APU access panel (320AB) is found at the bottom surface of the tail-cone. The panel shape agrees with the contour of the tail-cone, and the panel is flush with the tail-cone surface when installed. The panel attaches to an aluminum support frame with quick-release fasteners.

The main access panel (320AB) is made from a carbon composite material. It has five plies of carbon fabric with a ply of copper mesh on the external side for lightning protection. There are six more plies of carbon fabric around the edges of the panel to make it stronger. There is one layer of fiberglass on the internal surface for protection against a galvanic potential with the aluminum support frame of the tail-cone.

The APU access panel has four co-cured stiffeners from the front to the rear along its internal surface. There are two openings in the panel which give an exhaust for the muffler drain, and the fuel and inlet plenum drain.

The APU access panel (320AB) gives access to remove and install the APU, muffler and other line replaceable units (LRUs) in the tail-cone. With the panel removed, the opening is 45 in (114.30 cm) long, 29 in (73.66 cm) wide at the front, and 19 in (48.25 cm) wide at the rear.

Auxiliary Power Unit (APU) Left Access Panel (320BL)

The APU left access panel (320BL) is found on the left side of the tail-cone, near the front edge of the tail-cone. The panel is flush to the tail-cone skin surface when installed and attaches to an aluminum support frame with quick-release fasteners.

The APU left access panel (320BL) is made from a carbon composite material. It has eleven plies of carbon fabric with a ply of copper mesh on the external side for lightning protection. There is one layer of fiberglass around the edges on the internal surface of the panel. This is for protection against a galvanic potential with the aluminum support frame of the tail-cone.

The APU left access panel (320BL) gives an opening for the insertion of a support equipment used to remove the APU. The panel also gives general access to the APU, liquid level gauge and other system components. With the panel removed, the opening is 9 in (22.86 cm) long by 6 in (15.24cm) high.

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The aircraft has many small service doors that you can open without tools. The data that follows includes their location and dimensions, their function, and the materials from which they are made.

The service doors system includes the components which follow:

Communication Door

The location of this door, which gives access to the ground communication panel, is on the left side of the aircraft at FS243.39. The light alloy door has a piano hinge and two quick-release latches. Also, there is a ground wire between the communication door and the aircraft fuselage for electrical bonding. The dimensions of the door are approximately 5.5 by 3.5 in (14 by 8.9 cm).

Refuel/Defuel Door

This door is found in the forward, right, wing-to-fuselage fairing at approximately FS474.00. It gives access to the refuel/defuel adapter. The internal and external skins of the door are made of graphite with Nomex honeycomb material between the skins. The dimensions of the door are approximately 12 by 10 in (30.5 by 25.4 cm). There is a key lock (optional) installed on this door. It is used to lock the door.

Ground-Air Servicing-Connection Door

For access to the connection for the ground-air supply there is a light-alloy door in the rear fuselage to the right of the lower center-line. The location of the door is between FS801.56 and FS815.46. The piano hinge is at BL0.00 and the door dimensions are approximately 10 by 7 in (25.4 by 17.8 cm). There are two quick-release latches to open and close the door. A bonding jumper bonds the door hinge to the structure of the aircraft.

Oxygen Fill-and-Indicator Door

This door gives access to the oxygen servicing point and is found on the right side of the fuselage at FS639.00. It is a light alloy door which has the approximate dimensions of 5.5 by 3 in (14 by 7.6 cm). The door has a piano hinge and two quick-release latches.

Ground-Power Access Door

The location of this door is at FS683.00 on the right side of the aircraft in the aft wing-to-fuselage fairing. It gives access to the ground-power-supply service panel. The door dimensions are approximately 9 by 8 in (23 by 20 cm). Two gooseneck hinges attach the door to the fairing and it is held in the closed position with two quick-release latches at the aft edge.

Lavatory-Waste Service Door

You can get access to the lavatory-waste service panel through a door on the right side of the aircraft at FS649.00 in the aft wing-to-fuselage fairing. The internal and external skins of the door are made of graphite with Nomex honeycomb material between the skins. The dimensions of the door are approximately 17 by 13 in (43 by 33 cm). Two gooseneck hinges attach the door to the fairing and it is held in the closed position with two quick-release latches at the aft edge.

Battery Access Door

This door is in the aft wing-to-fuselage fairing on the left side of the aircraft at FS652.00. It gives access to the aircraft main batteries and the dimensions are approximately 27 by 18 in (68 by 45 cm). The internal and external skins of the door are made of graphite with Nomex honeycomb material between the skins. Two gooseneck hinges attach the door to the fairing. The battery access door has a seal around the edge that supplies weather protection to the battery compartment. There is a key lock (optional) installed on this door. It is used to lock the door.

Because the door is large, a proximity sensor is installed to give the flight crew an indication if it is open on the ground, or if it opens in flight. The battery access door is the only one of the service doors that is monitored by a proximity sensor.

Battery Access-Door Latch-Mechanism

The battery access door is held in the closed position with a pressure sensitive latch-mechanism at the aft edge. This latch mechanism opens if the air pressure in the area of the battery is 2 psi (13.8 kPa) more than the ambient pressure.

Refuel/Defuel Control-Panel Door

The location of this door is at FS474.00 on the right side of the aircraft in the forward wing-to-fuselage fairing. It gives access to the refuel/defuel computer. The door dimensions are approximately 12 by 6 in (30 by 15 cm). The internal and external skins of the door are made of graphite with Nomex honeycomb material between the skins. Two gooseneck hinges attach the door to the fairing and it is held in the closed position with two quick-release latches at the aft edge.

Outflow-Valve Access Door

This door is found in the forward, right, wing-to-fuselage fairing at FS433.00 and it gives access to the outflow valve access panel. The dimensions of the door are approximately 15 in (38 cm) by 19 in (48 cm). The internal and external skins of the door are made of graphite with Nomex honeycomb material between the skins. Two gooseneck hinges attach the door to the fairing. There is a key lock (optional) installed on this door. It is used to lock the door.

Outflow-Valve Access-Door Latch-Mechanism

The outflow-valve access door is held in the closed position with a pressure sensitive latch-mechanism at the aft edge. This latch mechanism opens if the air pressure behind the door is 2 psi (13.8 kPa) more than the ambient pressure.

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This section gives the data on access panels which are installed on the pressurized part of the aircraft fuselage. Screws attach each panel to the fuselage skin and the panels have seals to prevent air pressure leaks.

The service panels system includes the access panels which follow:

Lower Nose-Compartment Panels

Two panels on each side of the nose fuselage give access to the avionic equipment and other components in the lower nose compartments. The location of the two forward panels is between FS266.00 and FS282.00, below the level of the flight compartment floor. The two aft panels are found between FS297.00 and FS312.00, at the same level as the forward panels. The aluminum alloy panels have two horizontal flanges on their inboard surfaces which keep the panels rigid. A series of fastener receptacles is attached to the inboard surface of each panel. There is a pressure seal installed between the panels and the inner surface of the fuselage skin.

Outflow-Valve Access Panel

A panel which gives access to the cabin pressurization outflow-valve is installed in the lower fuselage structure between FS454.00 and FS470.00. A coupling holds the outlet of the valve in a circular adapter which is a part of the structure of the panel. A location pin in the adapter makes sure that the valve is installed in the correct position. Also, a flapper valve is a part of the outflow-valve access panel. This flapper valve closes the opening of the outflow valve, in the event of an emergency landing on water (ditching), to increase aircraft floatation time. The access panel attaches to the lower skin with screws and Livelock fasteners which are sealed to prevent air leaks. An Elastomer seal is installed between the access panel and the inboard surface of the fuselage skin. There is a bonding jumper connected between the outflow valve and a bracket on the access panel.

Note:
To get to this panel you must first open an access door in the forward wing-to-fuselage fairing.

Pressure-Floor Access Panels

There are four access panels installed in the fuselage skin structure in the area above the wing installation forward and aft of FS544.00. They are removed to do inspections of components between the fuselage and the wing. To get to these panels you must first remove sections of the flight compartment floor. A series of bolts holds each panel in position with a seal between the panel and the inner surface of the fuselage lower skin. After installation, sealant is applied around the edges of the panels to prevent air pressure leaks.

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Component Location Index
IDENT	DESCRIPTION	LOCATION	IPC REF
-	AFT EQUIPMENT-COMPARTMENT DOOR	ZONE(S) 182GL	52-41-01
-	APU ACCESS PANEL	ZONE(S) 320	52-43-01
-	APU LEFT ACCESS-PANEL	ZONE(S) 320	52-43-09
-	EXTERNAL-COMMUNICATIONS  SERVICING-CONNECTION DOOR	ZONE(S) 121AL	52-44-01
-	REFUEL/DEFUEL DOOR	ZONE(S) 181CR	52-44-05
-	GROUND-AIR SERVICING-CONNECTION DOOR	ZONE(S) 311AL	52-44-13
-	OXYGEN FILL-AND-INDICATOR DOOR	ZONE(S) 242AR	52-44-17
-	DC GROUND-POWER-CONNECTION DOOR	ZONE(S) 182FR	52-44-21
-	LAVATORY-WASTE SERVICE DOOR	ZONE(S) 182ER	52-44-25
-	BATTERY ACCESS DOOR	ZONE(S) 182DL	52-44-31
-	REFUEL/DEFUEL CONTROL-PANEL DOOR	ZONE(S) 181DR	52-44-33
-	LOWER NOSE-COMPARTMENT PANEL, AFT (LH)	ZONE(S) 141BL	52-45-01
-	LOWER NOSE-COMPARTMENT PANEL, AFT (RH)	ZONE(S) 142BR	52-45-01
-	LOWER NOSE-COMPARTMENT PANEL, FORWARD (LH)	ZONE(S) 141AL	52-45-01
-	LOWER NOSE-COMPARTMENT PANEL, FORWARD (RH)	ZONE(S) 142AR	52-45-01
-	OUTFLOW-VALVE ACCESS PANEL	ZONE(S) 181BR	52-45-13
-	PRESSURE-FLOOR ACCESS PANEL, AFT (LH)	ZONE(S) 161BL	52-45-17
-	PRESSURE-FLOOR ACCESS PANEL, AFT (RH)	ZONE(S) 162BR	52-45-17
-	PRESSURE-FLOOR ACCESS PANEL, FORWARD (LH)	ZONE(S) 161AL	52-45-17
-	PRESSURE-FLOOR ACCESS PANEL, FORWARD (RH)	ZONE(S) 162AR	52-45-17

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