Hyd Pumps

[JAG]

GM Poland,
Are you sure you have a pump problem, and not an internal leak on an actuator? How long does it take for the landing gear to go up and down - is it within limits per the manual? Did you compare cycle times in flight versus use of hydraulic cart?

By using an external hydraulic cart, you take your pump out of the system and are able to compare the two. If the external cart is faster, then likely you have leakage in your pump. If they both exceed the time limit, you likely have an internal leakage and most often in an actuator. Lastly, it could be internal leakage in the power pack.

If your handle takes 8 seconds to go to neutral, you are still within limits. Cessna allows 3 to 9 seconds for the time-delay valve to release (at room temperature) - longer delay if it is colder. This can also be adjusted if you need, but keep the setting in the mid-range to ensure enough time for the gear doors to be full closed.

Jeff