Door assembly with shear layer control aperture

There is described a vehicle door assembly with shear layer control for controlling the airflow in and around an aperture in the vehicle fuselage. The vehicle door assembly consists of an upper door and a lower door, both slidably mounted to the exterior surface of the vehicle fuselage. In addition, an inner door is slidably mounted beneath the upper door. Beneath the inner door is an aperture assembly having an aperture opening positionable to be substantially flush with the exterior surface of the vehicle fuselage. Also provided are means for positioning the aperture assembly in an upward and downward direction in relation to the vehicle fuselage.