X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 03 Apr 2012 10:21:24 -0400 Message-ID: X-Original-Return-Path: Received: from tx2outboundpool.messaging.microsoft.com ([65.55.88.12] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTPS id 5466035 for lml@lancaironline.net; Mon, 02 Apr 2012 22:42:51 -0400 Received-SPF: pass receiver=logan.com; client-ip=65.55.88.12; envelope-from=rpastusek@htii.com Received: from mail40-tx2-R.bigfish.com (10.9.14.250) by TX2EHSOBE008.bigfish.com (10.9.40.28) with Microsoft SMTP Server id 14.1.225.23; Tue, 3 Apr 2012 02:42:14 +0000 Received: from mail40-tx2 (localhost [127.0.0.1]) by mail40-tx2-R.bigfish.com (Postfix) with ESMTP id A45922400C0 for ; Tue, 3 Apr 2012 02:42:14 +0000 (UTC) X-SpamScore: -9 X-BigFish: PS-9(zzc85fh98dK179dNzz1202hzz8275bh8275dhz31h2a8h668h839hd25h) X-Forefront-Antispam-Report: CIP:157.56.245.5;KIP:(null);UIP:(null);IPV:NLI;H:CH1PRD0710HT004.namprd07.prod.outlook.com;RD:none;EFVD:NLI Received-SPF: softfail (mail40-tx2: transitioning domain of htii.com does not designate 157.56.245.5 as permitted sender) client-ip=157.56.245.5; envelope-from=rpastusek@htii.com; helo=CH1PRD0710HT004.namprd07.prod.outlook.com ;.outlook.com ; Received: from mail40-tx2 (localhost.localdomain [127.0.0.1]) by mail40-tx2 (MessageSwitch) id 1333420930764396_20480; Tue, 3 Apr 2012 02:42:10 +0000 (UTC) Received: from TX2EHSMHS025.bigfish.com (unknown [10.9.14.254]) by mail40-tx2.bigfish.com (Postfix) with ESMTP id AB8C82E00B4 for ; Tue, 3 Apr 2012 02:42:10 +0000 (UTC) Received: from CH1PRD0710HT004.namprd07.prod.outlook.com (157.56.245.5) by TX2EHSMHS025.bigfish.com (10.9.99.125) with Microsoft SMTP Server (TLS) id 14.1.225.23; Tue, 3 Apr 2012 02:42:10 +0000 Received: from CH1PRD0710MB367.namprd07.prod.outlook.com ([169.254.7.235]) by CH1PRD0710HT004.namprd07.prod.outlook.com ([10.255.152.39]) with mapi id 14.16.0143.003; Tue, 3 Apr 2012 02:42:08 +0000 From: Robert R Pastusek X-Original-To: Lancair Mailing List Subject: RE: [LML] LIV landing gear anomaly Thread-Topic: [LML] LIV landing gear anomaly Thread-Index: AQHNEM8+TZKCqjB5FEyasKVL0zvTS5aIY3RA X-Original-Date: Tue, 3 Apr 2012 02:42:07 +0000 X-Original-Message-ID: <41361035E6613244A377D5AC3BF5EFDD01C010@CH1PRD0710MB367.namprd07.prod.outlook.com> References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [72.66.86.7] Content-Type: multipart/alternative; boundary="_000_41361035E6613244A377D5AC3BF5EFDD01C010CH1PRD0710MB367na_" MIME-Version: 1.0 X-Original-Return-Path: rpastusek@htii.com X-OriginatorOrg: htii.com --_000_41361035E6613244A377D5AC3BF5EFDD01C010CH1PRD0710MB367na_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Fred wrote: Here is an interesting couple of events 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 stayed down and showed green, and the nose stayed down= and showed green. Makes for a funny looking light display on the panel. R= ecycled gear, 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. Recycled gear, no problem. 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 abo= ut 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 th= e nose wheel banged against the stop. Hmmmm.... Our initial theory was electrical contactor fault, but nothing was found in= ground tests. Initial theories about pressure switch dead band (checked OK= , about 1100 on, 1200-1220 off) went out the window with the results of the= ground retraction tests. Thoughts among the landing gear cognoscenti? Fred, My two cents: Either low system pressure (do you have/can you plumb in a ga= uge?)-a stuck bypass in the pump that "resets," a bad pressure switch, or i= ntermittent 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 s= ystem. This latter is less likely, but of course, more serious. The nose ge= ar coming up first is my clue that a blockage might be the problem; especia= lly if the pressure remains high. You may recall that there is a restrictor= fitting (90 degree elbow, painted red) in each of the actuators, plus a sp= ring loaded one-way valve on the aircraft centerline at the back of the gea= r box. PITA to do so, but I'd check the all for debris. Good Luck, Bob --_000_41361035E6613244A377D5AC3BF5EFDD01C010CH1PRD0710MB367na_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Fred wro= te:

Here is an inter= esting couple of events with nothing relevant found in the archives. &= nbsp; Aircraft has an estimated 300 take off and landing cycles since new.

 

About three flig= hts a go I took off and raised the gear.   One main came up, show= ed yellow, one stayed down and showed green, and the nose stayed down and showed green.  Makes for a funny looking light displa= y on the panel. Recycled gear, no problem, and none in subsequent= flights. 

 

Last flight, aft= er flying an hour to a fly in, staying five hours (cool day), I took off, n= ose gear retracted and showed yellow, but mains stayed down and showed green.  Recycled gear, no problem. =

 

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 about 20-30 pounds of "air load" to the left main before= retraction but to no effect.  Again,  nose came up first and mai= ns followed immediately after the nose wheel banged against the stop.&= nbsp; Hmmmm....

 

Our initial theo= ry was electrical contactor fault, but nothing was found in ground tes= ts. Initial theories about pressure switch dead band (checked OK, about 1100 on, 1200-1220 off) went out the window with the re= sults of the ground retraction tests.

 

Thoughts among t= he landing gear cognoscenti?

 

Fr= ed,

My two c= ents: Either low system pressure (do you have/can you plumb in a gauge?)= 212;a stuck bypass in the pump that “resets,” 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 the pressure remains high. You may recall that there is a restrictor fitting (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 s= o, but I’d check the all for debris.

&nb= sp;

Good Luc= k,

Bob=

 

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