Usually
that indicates a high to low internal valve leak.
-----Original Message-----
From: Lancair Mailing List
[mailto:lml@lancaironline.net] On Behalf Of Jeffrey
Liegner, MD
Sent: Tuesday, June 16, 2009 7:16
PM
To: lml@lancaironline.net
Subject: [LML] Re: Continuous
running hydraulic pump
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.
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