Structural damage may be caused if more
than one person is on the cabin door at a
time. The door is weight limited to 300
pounds or less.
A swing-down door (fig. 2-9), hinged at the bot-
tom, provides a stairway for normal and emergency
entrance and exit. Two of the steps are movable and
fold flat against the door in the closed position. A
step folds down over the door sill when the door
opens to provide a platform (step) for door seal pro-
tection. A plastic encased cable provides support for
the door in the open position, a handhold, and a
convenience for closing the door from inside. A
hydraulic damper permits the door to lower gradu-
ally during opening. A rubber seal around the door
seals the pressure vessel while the aircraft is in
flight. The door locking mechanism is operated by
either of the two mechanically interconnected han-
dles, one inside and the other outside the door.
When either handle is rotated, three rotating cam-
type latches on either side of the door capture posts
mounted on the cargo door. In the closed position,
the door becomes an integral part of the cargo door.
A button adjacent to the door handle must be
depressed before the handle can be rotated to open
the door. A bellows behind the button is inflated
when the aircraft is pressurized to prevent acciden-
tal unlatching and/or opening of the door. A small
round window just above the second step permits
observation of the pressurization safety bellows. A
placard adjacent to the window instructs the opera-
tor that the safety lock arm is in position around the
bellows shaft which indicates a properly locked
door. Pushing the red button adjacent to the window
will illuminate the inside door mechanism. A
CABIN DOOR annunciator light on the caution/
advisory panel will illuminate if the door is not
closed and all latches fully locked. The cabin door
opening is 21.5 inches wide by 50.0 inches high.
b. Cargo Door. A swing-up door (fig. 2-9)
hinged at the top, provides cabin access for loading
cargo or bulky items. After initial opening force is
applied, gas springs will completely open the cargo
door automatically. The door is counterbalanced
and will remain in the open position. A door sup-
port rod is used to hold the door in the open posi-
tion, and to aid in overcoming the pressure of the
gas spring assemblies when closing the door. Once
closed, the gas springs apply a closing force to assist
in latching the door. A rubber seal around the door
seals the pressure vessel while in flight. The door
locking mechanism is operated only from inside the
aircraft, and is operated by two handles, one in the
bottom forward portion of the door and the other in
the upper aft portion of the door. When the upper
aft handle is operated per placard instructions, two
rotating cam-type latches on the forward side of the
door and two on the aft side rotate, capturing posts
mounted on the fuselage side of the door opening.
The bottom handle, when operated per placard
instructions, actuates four pin lug latches across the
bottom of the door. A button on the upper aft han-
dle must be pressed before the handle can be
released to open or latch the door. A latching lever
on the bottom handle must be lifted to release the
handle before the lower latches can be opened.
These act as additional aids in preventing accidental
opening or unlatching of the door. The cabin and
cargo doors are equipped with dual sensing circuits
to provide the crew remote indication of cabin/cargo
door security. An annunciator light placarded
CABIN DOOR will illuminate if the cabin or cargo
door is open and the BATT switch in ON. If the bat-
tery switch is OFF, the annunciator will illuminate
only if the cargo door is not securely closed and
latched. The cargo door sensing circuit receives
power from the hot battery bus. The cargo door
opening is 52.0 inches wide by 52.0 inches high.
Insure that the cabin door is closed and
locked. Operating the cargo door while
the cabin door is open may damage the
door hinge and adjacent structure.
(1.) Opening cargo door.
Avoid side loading of the gas springs to
prevent damage to the mechanism.
Handle access door (lower for-
ward corner of door) -Unfasten
Handle - Lift hook and move to
Handle access door - Secure.
Handle access door (upper aft cor-
ner of door) - Unfasten and open.
Handle - Press button and lift to
OPEN position then latch in