SAE AS 6026A:2013 pdf free

SAE AS 6026A:2013 pdf free.Control Unit, Pressure Generating, Manually Operated,Aircraft Hydraulic Brake System
Prior to beginning quantity production, preproduction samples shall be subjected to preproduction testing. The preproduction sample shall be produced by the same method and of the same material that will be used for quantity production of the item.
Design of control units for manually operated hydraulic brake systems shall consist of a mechanically actuated hydraulic power generator. The incorporation into the unit of a reservoir to maintain a reserve supply of fluid shall be optional. This unit shall be operable by the pilot’s brake pedal, and it shall conform to the applicable requirements of Specification MIL-B-8584.
Operating Pressure: Normal operating pressure shall be that pressure required to lock the wheels of the airplane, assuming a coefficient of friction of 0.31 between the tires and the ground.Maximum operating pressure shall be that pressure required to lock the wheels of the airplane,assuming a static coefficient of friction of 0.55 between the tires and the ground.
Pumping: Control units shall be designed to permit “pumping up” of the hydraulic pressure in a brake system where the control unit travel to operate the brake may become greater than the travel normally required, such as in the case of a failed packing in the unit, or a leak in the brake system.It shall also serve to facilitate bleeding of air from the brake system and maintaining an airfree system. The pumping valve shall remain sealed at all times during the operating stroke of the unit, but shall be designed to open immediately at any time when the brake line hydraulic pressure may become appreciably less than the reservoir pressure. Pressure drop through the valve during pumping shall be sufficiently low to assure compliance with the pumping test specified in 4.8.3.
Return Mechanism: A means shall be provided within the unit to return the pressure generator to its relaxed position upon release of the actuating force. The return rate shall be sufficiently rapid to provide a pressure drop in the unit enough greater than that in the brake system to assure a buildup to the required pressure within the required number of pumping strokes when tested as specified in 4.8.3.SAE AS 6026A pdf download.