Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml
Date: Fri, 01 Nov 2002 11:11:43 -0500
Message-ID: <redirect-1850415@logan.com>
Mime-Version: 1.0
From: "Lorn H. Olsen" <lorn@dynacomm.ws>
Subject: Almost Back Flying
Content-Type: text/plain; charset="us-ascii" ; format="flowed"

After my hard landing in July, the plane is almost back in good shape.

We fixed an oil leak 2 weeks ago.

On my last trip to Florida, I stopped in Atlanta and glued a 1/32" 
patch on the nose gear strut to stop it from hitting when it was 
retracted. Immediately after that, the pump would run for about 1/4 
of a second every 4 seconds. I pulled the circuit breaker(CB) for 
about 30 minutes and when I pushed it back in, everything seemed to 
work OK. On my return trip from Sarasota, the problem was back. Every 
4 seconds the pump would run for about 1/4 of a second. Of course I 
removed the patch to see if that would stop the problem. It did not.

On the hydraulic high side. My unit runs from about 800 lbs to 1,200 
lbs. The pump can pump at about 100 lbs per second. I am getting this 
information from experience not manuals. If the struts leaked enough 
to get down to 800 lbs in 4 seconds, then the pump should have run 
for 4 seconds to pump the system back up. I was convinced by this 
that I had a bad high pressure switch that was starting the pump when 
the pressure was just 25 lbs. low.

When flying the airplane for 15 minutes with the circuit breaker 
pulled and then pushing it back in, the pump would run for about 3 
seconds. This 3 second run convinced me that I also had a strut leak.

I ordered rebuild kits for all of the struts and pressure gauges to 
install that would help me isolate this and future problems. All 
parts were ordered from Lancair. The nose strut and dump valve were 
installed new in March, 2002.

The plane went into the shop yesterday morning. When on jacks, with 
the gear up, the pump ran every 4 seconds as usually. The mechanic 
had me lower the gear 1/2 way. He then moved the left wheel up and 
down. The right wheel went down and up. He also pulled and pushed on 
the nose gear wheel and door. The other wheels pushed and pulled, 
just like you would expect. We tried the test again with the wheels 
up and the pump did not run. We left the plane sit with the gear up 
for 15 minutes and the pump did not run. I will try again today but 
for now, pushing the gear up and down has fixed the problem.

The only thing that I think could have happened is that air had 
lodged somewhere in a critical part of the system like the high 
pressure switch. I had dumped the gear a couple of times but did not 
let the pump run. According to Scott, this pump running would have 
cleared out any air.

-- 
Lorn H. 'Feathers' Olsen, MAA, DynaComm, Corp.
248-478-4301, mailto:lorn@dynacomm.ws
LNC2, O-320-D1F, N31161, Y47, SE Michigan