Basic Hydraulics: DGCA Technical General questions

Hydraulics uses an almost incompressible fluid to move heavy loads with light controls. Pascal's law starts it: pressure in a confined fluid acts equally in all directions, so force is pressure times area.

The 50 questions blend force and pressure arithmetic with component purposes, valve types and fluid specifications. DGCA papers have carried 8 of them.

At equal pressure a larger actuator gives more force but moves more slowly for the same flow. Once the system is pressurised, the accumulator gauge reads system pressure, not the gas pre-charge. Mineral fluid to DEF STAN 91-48 is red and Skydrol is a phosphate ester; never mix them, as each needs its own seals.