News: Added Links For Twin Commander and Facebook Pages

Login  |  Register

Author Topic: 560A Hydraulic failure  (Read 144 times)


  • Newbie
  • *
  • Posts: 4
560A Hydraulic failure
« on: April 12, 2019, 05:12:00 pm »
After 9 months working on an annual, most of the time searching for parts, my 560A is flying again. 15 hours after annual, I had a complete hydraulic failure. Gear dropped and locked nicely but no flaps or brakes made for a challenging landing. Hydraulic tank was full at departure but bone dry 2 hours later. I have been putting the gear selector switch to neutral, which appears to stop the pump from running, but this time I did not and although there are no signs of leaks, certainly the fluid pumped overboard. There are no proxy switches on the gear up side, and only the squat switch on the gear knuckle which activates the gear down lights. Do I have a defective hydraulic component that would turn the pump off when gear is up, or is it a common practice to have to put the gear handle to neutral to stop the pump from running like the old Cessna 210's of the 1960's? Thx. Sparks Stiles, St. Petersburg, Fl.

Adam Frisch

  • Administrator
  • Hero Member
  • *****
  • Posts: 1229
    • Adam Frisch FSF
Re: 560A Hydraulic failure
« Reply #1 on: April 13, 2019, 06:18:17 am »
Used to be common problem with some Commanders. In fact, there was a procedure to pull the aux hydraulic pump breaker just after plane was cleaned up only to push it in just before landing to avoid it from pumping it all overboard in case of hydraulic leak. So, you have a leak somewhere and the pump just kept going. Do you have a breaker for the aux pump on the panel?
Slumming it in the turboprop world - so you don't have to.


  • Hero Member
  • *****
  • Posts: 1874
Re: 560A Hydraulic failure
« Reply #2 on: April 13, 2019, 12:13:56 pm »
Does the 560A have an electric pump and a single engine driven pump, or two engine driven pumps, or what?

The procedure Adam is referring to is because on later models (maybe the 560A as welll?) there is a standpipe within the hydraulic reservoir which is only accessed by the electric pump, and the electric pump only actuates when the pressure is below what the engine driven pump(s) can provide.


  • Administrator
  • Hero Member
  • *****
  • Posts: 1110
Re: 560A Hydraulic failure
« Reply #3 on: April 14, 2019, 08:30:37 am »
It is Still a very good procedure as Don points out.  And look around good because you will find the leak somewhere.  there are a lot of places for it to hide.  look at belly first as there are a lot if connectors in tail and nose area.
You can't win an argument with an ignorant person,  they'll just drag you down to their level and beat you with experience.


  • Full Member
  • ***
  • Posts: 199
Re: 560A Hydraulic failure
« Reply #4 on: April 14, 2019, 11:46:37 am »
Glenn is correct.  My recent hydraulic leak occurred just above the baggage compartment door and leaked down into the belly and onto the hangar floor.  Fortunately, I still had enough hydraulic fluid when I landed and taxied in that all my systems worked.  I did not even know I had the leak.  I sure knew the next day, though, when I went into the hangar to clean the aircraft.