Upwardly opening plug-type door for use as an over-wing emergency hatch

A latching mechanism for use on board an aircraft in connection with an upwardly opening plug-type door system, said door system including a door having laterally mounted side rollers, and a pair of substantially parallel guide rails mounted to the fuselage of said aircraft on laterally opposite sides of said door, said door's side rollers being in rolling engagement with said rails, for guiding upward opening and downward closing movements of said door, the latching mechanism comprising:

• a torque shaft rotatably mounted to said door and extending transversely across said door;
• a handle connected to said torque shaft for rotating the same, said handle being accessible from an interior side of said door, and wherein said torque shaft and said handle are both carried by said door as it opens and closes;
• and
• at least one latch pin member retractably mounted to said door adjacent an upper portion of said door, said latch pin member being axially movable in a direction that is generally perpendicular to the axis of rotation of said torque shaft, and said latch pin member being connected to said torque shaft in a manner so that said pin member retracts in response to clockwise rotation of said torque shaft, said pin member being normally extended when said door is closed, and in such position, said pin member being in engagement with a catch that is fixedly connected to fuselage structure immediately above said door, to prevent upward opening movement of said door, and wherein said clockwise rotation of said torque shaft includes clockwise rotation of said torque shaft from a first to a second position, and including a spring connected to said torque shaft in a manner so that said spring first opposes at least the beginning of said clockwise rotation, and then assists at least the end of said clockwise rotation.