TM 1-1510-218-10 2-28 The  cargo  door  is  a  structural  panel  and shall be closed for flight. c.   Cargo Door  D  T .  A swing-up door, 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 support assembly rod is used to hold the door in the open position 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  handle  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 is ON.  If the battery  switch  is  OFF,  the  annunciator  will illuminate only   if   the   cargo   door   is   not   closed   and   securely latched.      The   cargo   door   sensing   circuit   receives power from the hot battery bus. CAUTION Ensure    the    cabin    door    is    closed    and locked.  Operating the cargo door while the cabin  door  is  open  may  damage  the  door hinges and adjacent structure. Avoid  side  loading  of  the  gas  springs  to prevent damage to the mechanism. (1)   To  open  the  cargo  door,  unfasten  and open   the   handle   access   door   at   the   lower   forward corner of the door.  Lift hook and move the handle to the    OPEN    position.        Secure    the    access    door.   Unfasten   and   open   the   handle   access   door   at   the upper aft corner of the door.  Press the button and lift the  handle  to  the    OPEN   position.    Latch  handle  in place.  Secure the access door.  Attach one end  of the door  support  assembly  to  the  cargo  door  ball  stud  on the forward side of the door.  Ensure the support rod detent pin is in place.  Push out on the cabin doorsill step, and allow the cargo door to swing open.  The gas springs  will  automatically  open  the  door.    Attach  the free  end  of  the  support  rod  to  the  ball  stud  on  the forward fuselage doorframe. (2)   To close the cargo door, detach the door support   rod   from   the   fuselage   doorframe   ball   stud.   Firmly grasp the free end of the door support rod while exerting  a  downward  force  to  overcome  the  pressure of the gas spring assemblies.  Remove the support rod from the door as the gas spring assemblies pass the over   center   position.      The   internal   pressure   of   the springs   is   reversed   forcing   the   door   to   the   closed position.    Using  the  finger  hold  cavity  in  the  fixed  air stair   doorstep,   pull   the   door   closed   to   permit   the latching  mechanism  to  engage.    Press  the  button  in the center of the handle at the upper aft corner of the door and pull the handle down until the handle latches into  position.    Pull  aft  on  the  handle  to  assure  it  is locked in place.  Close and fasten access door.  Move the handle at the bottom forward corner of the door to the full forward position.  Ensure the safety hook locks the handle in position by pulling aft on the handle. d.  Emergency.      The  cabin  emergency  hatch, placarded  EXIT  – PULL, is located on the right cabin sidewall  just  aft  of  the  copilot's  seat.    The hatch may be released from the inside with a pull-down handle.  A flush  mounted  pull  out  handle  allows  the  hatch  to  be released  from  the  outside.    The  hatch  is  of  the  non- hinged  plug  type,  which  removes  completely  from  the frame  when  the  latches  are  released.   The hatch can be key locked from the inside to prevent opening from the outside.   The  inside  handle  will  unlatch  the  hatch whether  or  not  it  is  locked  by  overriding  the  locking mechanism.   The key lock should be unlocked prior to flight to allow removal of the hatch from the outside in the  event  of  an  emergency.    The  key  remains  in  the lock  when  the  hatch  is  locked  and  can  be  removed only when the hatch is unlocked.   The key slot is in the vertical position when the hatch is unlocked.  Removal of the key from the lock before flight assures the pilot that   the   hatch   can   be   removed   from   the  outside  if necessary. (1)   A  wiper  type  disconnect  for  the  air  duct that supplies the air to the eyeball outlet in the cabin emergency  hatch  is  located  on  the  upper  aft  edge  of the   door.      As   the   hatch   is   removed,   the   duct   is disconnected since it is an integral part of the hatch. (2)   An  electrical  disconnect  located  on  the lower  forward  edge  of  the  hatch  will  unplug  as  the WARNING