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Landing gear hydraulics

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Aircraft Systems, Commercial Pilot

In my POH (tb20) it mentions that it is normal for the landing gear pump to activate a few times per hour in order to hold pressure to keep the gear up. Does this mean that every time it runs, it is indicating that I am losing pressure, and therefore also losing hydraulic fluid?


second question, sort of related.  What is a 'power pack' in relation to the electric motor that pumps hydraulic fluid for the gear? Is it a secondary, hivolts power battery? If so, does this mean that is holds a charge separate from the battery, and that in an alternator failure, lowering the landinwithout through the use of the electric pump will not quickly drain my battery?

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1 Answers

  1. Best Answer

    lo_fly on Jan 30, 2013

    1. You’re losing pressure because of a slight back-flow of hydraulic fluid: the actuator can’t be 100% sealed so the high pressure will push some fluid back in the line.
    2. Power pack = AC-DC converter + electric motor + hydraulic pump. The hydraulic pump used to encrease fluid pressure is driven by an electric motor that uses electrical energy, converted from alternate to direct current, from the alternator.

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