Mailing List lml@lancaironline.net Message #55855
From: Wolfgang <Wolfgang@MiCom.net>
Sender: <marv@lancaironline.net>
Subject: LIV-P Bad Master relay???
Date: Sun, 25 Jul 2010 13:36:20 -0400
To: <lml@lancaironline.net>
The accumulator is not your problem.
I doubt that pressure switches or master relay are your problem either.
If the system does not get up to pressure, the pump will keep running.
Your pump may have a bad o-ring causing it to not give full pressure.
Put some pressure gages on the system and see what's happening.
 
Wolfgang
 
 
From: "Doug Johnson" <Lancair1@bellsouth.net>
Sender: <marv@lancaironline.net>
Subject: LIV-P Bad Master relay???
Date: Sat, 24 Jul 2010 15:21:10 -0400
To: lml@lancaironline.net

Folks, I have a question: What would be the symptoms of a master relay or pressure switch going bad with reference to the hydraulic system?

The plane: IV-P, about 1150hrsTT, in the air over 13years now

The issue: I have had a couple of intermittent (i.e., un-reproducible) issues related to  1) the flaps having difficulty deploying against resistance  at anything over 140kts (used to be no sweat putting them down at 172kts); and 2) a couple of times the amber hydraulic power pack “on” light stays on constantly.  In terms of #1, I replaced the accumulator with a partially used one (Lancair was out of stock) and it only partially helped the problem. I now have a new one from Lancair, and plan on installing it this week. #2 has me perplexed, however. Just in the last couple of weeks, I have had time when the amber light (hydraulic pump) won’t go out. After a minute or so, I had to pull the 50amp circuit breaker, and when I re-set it, the pump and light stayed off. Today, however, there was  a new twist—after landing, I put the flap handle UP and nothing happened—the flaps didn’t move, and the pump did not come on. I recycled the flap handle a couple of times and the pump came on, flaps came up, and pump STAYED on. Pulled and reset 50 circuit breaker, and pump went off but then right back on with the reset CB!. I shut down completely, and then fired back up—all was well. Of note, there has been no problem or lag with the gear rectract or deployment that I can tell.

So, I am wondering if there is more than just a weak accumulator going on here. Does this story sound familiar to anyone? Anything else I should look at while I am at it? Does it sound like a bad master relay or pressure switch?

Thanks in advance for your thoughts/advice.

Doug Johnson, MD

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