Mailing List lml@lancaironline.net Message #51789
From: Dan Reagan <dreagan@fuse.net>
Sender: <marv@lancaironline.net>
Subject: Re: Continuous running hydraulic pump
Date: Wed, 17 Jun 2009 18:45:57 -0400
To: <lml@lancaironline.net>
Re: Continuous running hydraulic pump
My flaps retain pressure on the ground when left in the down position.  They bleed off in the nuetral position.
 
Dan Reagan
IVP 650 hrs.
----- Original Message -----
Sent: Tuesday, June 16, 2009 7:15 PM
Subject: Re: Continuous running hydraulic pump

More observation:
If I leave my flap lever in the neutral position, the hydralic reservoir remains fully pressurized, and next time I fly there's no need for the pump to come on during power up to recharge the system.

I understand that some planes/pilots must leave their flap lever in the UP position, or the DOWN position to retain hydralic pressure until the next flight.  If I did this, all pressure would be released.  Why the difference with what is the same valve?

I also have seen the flaps move (briefly) in the opposite direction if lever is positioned just slightly off of neutral, during routine operations; I agree that this is a quirk in the internal valve.

Jeff Liegner
LIVP


This is case of creating a problem that wasn't there.  My experience might ease someone's tension in the future.
 
While practicing an approach I got a "check engine" from the Chelton.  The indication was low voltage.  I quickly saw the hydraulic pump was running continuously.  I pulled the hydraulic pump breaker.  I got a "gear transition" light so I suspected no hydraulic pressure which was confirmed when I looked at the gauge.
 
I figured the best thing to do was to leave everything as it was and hand pump the gear down and land.  This worked just fine.
 
Now the problem was that for the first time in over 600 hours of flying this thing, when I had set the flaps at 10 degrees I had left the flap handle a little out of the detent and the valve was just dumping the high side pressure to the low side and just kept the hydraulic pump running.
 
Some days I think that if every thing is going well I just create a problem for the practice.  At least my rebuild of the gear hand pump worked well.
 
Dan Reagan
IVP 650 hours

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