Mailing List lml@lancaironline.net Message #54482
From: Charlie Kohler <charliekohler@yahoo.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Turbine IVP Landing Accident Video
Date: Tue, 16 Feb 2010 13:26:19 -0500
To: <lml@lancaironline.net>

Hi Bob,

I think if you'll look LIV hydraulic schematic over, you will see that -- the shuttle valve determines which pressure source to use. If the electric hydraulic pump is inoperative--then the hand pump will provide enough pressure to extend the main landing gears provided the system is intact.

Any leak after the gear selector will dump all (electric or hand pump--in the down position) hydraulic pressure. That is why the designers of this system installed the nose gear gas spring.

Anything after the gear selector-- well render the hydraulics inoperative. Including the hand pump. That is why the designer put a gas spring to extend the nose gear. To save our wallets.

 
Charlie K.
 
See me on the web at
 



From: "marv@lancair.net" <marv@lancair.net>
To: lml@yahoo.com
Sent: Tue, February 16, 2010 9:10:13 AM
Subject: [LML] Re: Turbine IVP Landing Accident Video

Posted for "Robert Pastusek" <rpastusek@htii.com>:

 Laurie,
 
First of all, a very nice job of taking care of this emergency! Also, thanks
 so much for the report to the rest of us. As you note, these things always
 provide useful information, and this one caused me to think again about my
 own airplane. Most of my IV-P electrical system is protected with fuses; the
 alternators and hydraulic pump being the exceptions, and with the CB's for
 these made very readily accessible for just the situation you encountered.
 My concern is that you didn't have sufficient hydraulic fluid to lower/lock
 the gear with the manual pump. I determined during construction that the
 pickup tube for the manual pump extended lower in the tank than the electric
 pump pickup, and just let it go at that. I did not test this at all.
 
 
 
 If you have any thoughts about why you didn't have enough fluid left to use
 the backup system, I'd be most appreciative. Could the pitch attitude of the
 aircraft had an effect? Other thoughts? Based on your experience, I'm
 thinking of draining down my system through the electric pump and then
 trying the manual pump. Like I said, I took this one on faith of the
 designer and did not test it, although it would have been easy to do during
 build.
 
 
 
 Again, nice job landing the aircraft, and I'm happy you sustained minimal
 damage in the process. Thanks especially for your comprehensive report. If
 you find more, especially about why the emergency pump didn't work, we'd all
 appreciate hearing.
 
 
 
 Bob Pastusek
 
For LOBO

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