X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 04 Apr 2012 16:08:27 -0400 Message-ID: X-Original-Return-Path: Received: from blu0-omc3-s22.blu0.hotmail.com ([65.55.116.97] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTP id 5467560 for lml@lancaironline.net; Tue, 03 Apr 2012 20:51:52 -0400 Received-SPF: neutral receiver=logan.com; client-ip=65.55.116.97; envelope-from=frederickmoreno@bigpond.com Received: from BLU0-SMTP329 ([65.55.116.74]) by blu0-omc3-s22.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Tue, 3 Apr 2012 17:51:18 -0700 X-Originating-IP: [123.211.168.143] X-Originating-Email: [frederickmoreno@bigpond.com] X-Original-Message-ID: X-Original-Return-Path: frederickmoreno@bigpond.com Received: from Razzle ([123.211.168.143]) by BLU0-SMTP329.phx.gbl over TLS secured channel with Microsoft SMTPSVC(6.0.3790.4675); Tue, 3 Apr 2012 17:51:16 -0700 MIME-Version: 1.0 X-Original-Date: Wed, 4 Apr 2012 08:50:54 +0800 Content-Type: multipart/alternative; charset="iso-8859-1"; boundary="------------Boundary-00=_UOJXC5G3LVC000000000" X-Mailer: IncrediMail (6295180) From: Frederick Moreno References: X-FID: FLAVOR00-NONE-0000-0000-000000000000 X-Priority: 3 X-Original-To: "Lancair Mail (lml@lancaironline.net)" Subject: Re: [LML] Re: LIV landing gear anomaly X-OriginalArrivalTime: 04 Apr 2012 00:51:17.0149 (UTC) FILETIME=[0AEFACD0:01CD11FD] --------------Boundary-00=_UOJXC5G3LVC000000000 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks for the ideas Bob. It is a bit of a bugger. Pressure indicates o= n my engine MOnitor, is fine. The debris going in and out of restrictors could be an issue, but getting both actuators at the same time? And aft4= er hundreds of gear cycles? It is truly a puzzlement. =0D =0D Just on general principles yesterday I replaced the solenoid contactor th= at operates the hydraulic motor. I replaced a starter contactor with a high quality continuous duty contactor. The reasoning is that we did detect s= ome slowness on some cycles suggesting an intermittent high resistance condit= ion The continuous duty contactor has a much lower pull-in current which makes it much easier on the pressure switch since it will be switching lo= wer currents. And the new contactor is capable of handling 85 amps, more tha= n enough for the motor. =0D =0D The contactor I got is rated for commercial offshore boat duty, equivalen= t of TSO for commercial boats, sold in the local auto shop of our regional town which is a seaport town. Cost $77 instead of $20. We shall see. =0D =0D Whenever I get something intermittent, I immediately think "electrical." = =0D =0D Fingers crossed. =0D =0D Puzzled Fred =0D =0D =0D =0D =0D -------Original Message-------=0D =0D From: Robert R Pastusek=0D Date: 3/04/2012 10:21:51 PM=0D To: lml@lancaironline.net=0D Subject: [LML] Re: LIV landing gear anomaly=0D =0D Fred wrote:=0D Here is an interesting couple of events with nothing relevant found in th= e archives. Aircraft has an estimated 300 take off and landing cycles sin= ce new.=0D =0D About three flights a go I took off and raised the gear. One main came = up, showed yellow, one stayed down and showed green, and the nose stayed down and showed green. Makes for a funny looking light display on the panel. Recycled gear, no problem, and none in subsequent flights. =0D =0D Last flight, after flying an hour to a fly in, staying five hours (cool d= ay) I took off, nose gear retracted and showed yellow, but mains stayed down and showed green. Recycled gear, no problem. =0D =0D When I got home, I jacked up the gear and did various retraction tests. = In each case, the nose came up first and mains followed. A buddy applied ab= out 20-30 pounds of "air load" to the left main before retraction but to no effect. Again, nose came up first and mains followed immediately after = the nose wheel banged against the stop. Hmmmm....=0D =0D Our initial theory was electrical contactor fault, but nothing was found = in ground tests. Initial theories about pressure switch dead band (checked O= K, about 1100 on, 1200-1220 off) went out the window with the results of the ground retraction tests. =0D =0D Thoughts among the landing gear cognoscenti?=0D =0D Fred,=0D My two cents: Either low system pressure (do you have/can you plumb in a gauge?)=97a stuck bypass in the pump that =93resets,=94 a bad pressure sw= itch, or intermittent power to the pump (+ lots of other things L ) OR a blockage = in the hydraulic system plumbing (bent/kinked line or hose) or debris in the system. This latter is less likely, but of course, more serious. The nose gear coming up first is my clue that a blockage might be the problem; especially if the pressure remains high. You may recall that there is a restrictor fitting (90 degree elbow, painted red) in each of the actuator= s, plus a spring loaded one-way valve on the aircraft centerline at the back= of the gear box. PITA to do so, but I=92d check the all for debris.=0D =0D Good Luck,=0D Bob=0D =0D =0D =0D =0D =20 --------------Boundary-00=_UOJXC5G3LVC000000000 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks for the ideas Bob.  It is a bit of a bugger.  Press= ure indicates on my  engine MOnitor, is fine.  The debris going= in and out of restrictors could be an issue, but getting both actua= tors at the same time?  And aft4er hundreds of gear cycles?  It= is truly a puzzlement.
 
Just on general principles yesterday I replaced the solenoid contact= or that operates the hydraulic motor.  I replaced a starter con= tactor with a high quality continuous duty contactor.  The reasoning= is that we did detect some slowness on some cycles suggesting = an intermittent high resistance condition.  The continuous = ; duty contactor has a much lower  pull-in current which makes it mu= ch easier on the pressure switch since it will be switching lower cu= rrents.  And the new contactor is capable of handling 85 amps, = more than enough for the motor. 
 
The contactor I got is rated for commercial offshore boat duty, equi= valent of TSO for commercial boats, sold in the local auto shop = ;of our regional town which is a seaport town.  Cost $77 instea= d of $20.  We shall see.
 
Whenever I get something intermittent, I immediately think "electric= al." 
 
Fingers crossed.
 
Puzzled Fred 
 
 
 
 
-= ------Original Message-------
 
Date: 3/04/2012 10= :21:51 PM
Subject: [LML] Re:= LIV landing gear anomaly
 

Fred wrote:

=

Here is an interesting couple of eve= nts with nothing relevant found in the archives.   Aircraft has= an estimated 300 take off and landing cycles since new.

 

About three flights a go I took off = and raised the gear.   One main came up, showed yellow, one sta= yed down and showed green, and the nose stayed down and showed green.&nbs= p; Makes for a funny looking light display on the panel. Recycled ge= ar, no problem, and none in subsequent flights. 

 

Last flight, after flying an hour to= a fly in, staying five hours (cool day), I took off, nose gear retracted= and showed yellow, but mains stayed down and showed green.  Re= cycled gear, no problem.

 

When I got home, I jacked up the gea= r and did various retraction tests.  In each case, the nose came up = first and mains followed.  A buddy applied about 20-30 pounds of "ai= r load" to the left main before retraction but to no effect.  Again,=   nose came up first and mains followed immediately after the nose w= heel banged against the stop.  Hmmmm....

<= /DIV>

 

Our initial theory was electrical co= ntactor fault, but nothing was found in ground tests. Initial t= heories about pressure switch dead band (checked OK, about 1100 on, = 1200-1220 off) went out the window with the results of the ground retract= ion tests.

 

Thoughts among the landing gear cogn= oscenti?

 

Fred,

My two cents: Either low system pressure (= do you have/can you plumb in a gauge?)=97a stuck bypass in the pump that = =93resets,=94 a bad pressure switch, or intermittent power to the pump (+= lots of other things L ) OR a blockage in the hydraulic = system plumbing (bent/kinked line or hose) or debris in the system. This = latter is less likely, but of course, more serious. The nose gear coming = up first is my clue that a blockage might be the problem; especially if t= he pressure remains high. You may recall that there is a restrictor fitti= ng (90 degree elbow, painted red) in each of the actuators, plus a spring= loaded one-way valve on the aircraft centerline at the back of the gear = box. PITA to do so, but I=92d check the all for debris.=

 

Good Luck,

Bob

 

 
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