Abstract: A single pintle arm-based structure is provided for mounting a machine gun on the exterior of a helicopter fuselage on the frame of or adjacent a gunner's cabin area side wall opening such as a window or door. The mounting structure permits horizontal pivotal motion of the single pintle arm and gun among lockable service, stowed, crew-served and full forward positions. The gun and the mounting structure, in their stowed position, are disposed externally of the helicopter, thereby permitting of the fuselage side wall opening, with the pintle arm being pivotable about an axis external to the fuselage.

Abstract: An ordnance mounting system for a helicopter operatively supports a weaponry support beam above an upwardly projecting floor obstruction in a cabin area of the helicopter, between opposite cabin door openings, with the support beam longitudinally extending transversely through the cabin area, and outer weaponry mounting end portions of the support beam projecting outwardly through the door openings beyond opposite fuselage side walls of the helicopter. The mounting system may be secured to door opening sill structures, or the cabin ceiling or side walls, and permits vertical bending flexure of the installed support beam due to flight and weaponry weight loads on the outer ends of the support beam.

Abstract: A retractable aircraft step module comprises a streamlined fairing having a recess for receiving a retractable step member which is connected to the fairing by spaced apart pivot links which together with the step member and the body member form a four bar linkage. The linkage includes a deflectable pivot connection between one of the links and the step member which provides a biasing force to maintain the step member in the retracted position. The deflectable pivot connection is provided by a pivot beam mounted on the step member and including a counterdeflection adjustment for preselecting the maximum biasing force. The step member and the fairing are adapted to mount on the exterior of an aircraft fuselage and are preferably constructed of reinforced plastic.