Testing aircraft hydraulic systems

Hydraulic systems perform multiple functions on modern aircraft. These include maneuvering and actuating the landing gear, brakes and flaps, and operating both primary and secondary flight controls, thrust reversers and spoilers. Hydraulic systems often have a direct impact on flight safety: landing gear, for example, must absorb landing loads to ensure stable operation. Because so many aircraft functions are critically dependent on hydraulic devices such as pumps, actuators, control surfaces and valves, this equipment must undergo intensive ground and flight testing.

Piezoresistive pressure sensors from Kistler are highly suitable for evaluating both static and dynamic pressure. Harsh conditions in test environments include extreme temperatures as well as high vibration and shock levels, so these sensors incorporate many design features that can easily overcome these challenges. The micro-machined silicon sensing element is fully isolated from the pressure media by a welded stainless steel diaphragm and a high-integrity seal assembly. The sensing element combines high stability with excellent repeatability. Piezoresistive transducers from Kistler are designed for survivability of up to 50 million full-scale cycles at 2 Hz; maximum pressure range capabilities of up to 350 bar (5,000 psi) or up to 10 bar differential (150 psi) are available, together with barometric pressure ranges.