X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 21 Apr 2014 11:43:52 -0400 Message-ID: X-Original-Return-Path: Received: from [107.14.166.232] (HELO cdptpa-oedge-vip.email.rr.com) by logan.com (CommuniGate Pro SMTP 6.0.9e) with ESMTP id 6831753 for lml@lancaironline.net; Thu, 17 Apr 2014 10:42:09 -0400 Received-SPF: none receiver=logan.com; client-ip=107.14.166.232; envelope-from=Wolfgang@MiCom.net X-Original-Return-Path: Received: from [74.218.201.50] ([74.218.201.50:1216] helo=lobo) by cdptpa-oedge01 (envelope-from ) (ecelerity 3.5.0.35861 r(Momo-dev:tip)) with ESMTP id 4A/AF-16062-E18EF435; Thu, 17 Apr 2014 14:41:34 +0000 X-Original-Message-ID: <47C7CC36DA064F62A55E383ECABEE421@lobo> From: "Wolfgang" X-Original-To: "William Ford" , References: Subject: Re: Gear Down...INOP X-Original-Date: Thu, 17 Apr 2014 10:41:28 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_006E_01CF5A29.966600E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5512 X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 This is a multi-part message in MIME format. ------=_NextPart_000_006E_01CF5A29.966600E0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable The problem is caused by the hudraulic pump not operating as desired. = The shuttle valve inside it comes off its end stop and traps fluid in = the lines. This trapped fluid expands with temperature increase = increasing pressure in the lines and trips the pressure switches. Since = the switches are now open, no electricity can get to the pump morot . . = . gear failure. There are three solutions to this problem. 1) add an accumulator to the hydraulic system. 2) rebuild and possibly modify the the pump=20 3) install my electric module that monitors the pressure switches and = automatically runs the pump to vent the offending pressures. Wolfgang ----- Original Message -----=20 From: William Ford=20 To: lml@lancaironline.net=20 Sent: Wednesday, April 16, 2014 10:06 AM Subject: Gear Down...INOP I believe that I recently experienced something in my Legacy that I = remember reading about but can't remember all the details. I looked = into the LML archives and was unsuccessful. Could someone out there = please briefly summarize the situation, reason and any possible remedies = for gear extension failure following high altitude cruise in cold air = followed by a decent and landing in hot air. I seem to remember a = discussion about boosted pressure in the hydraulics plumbing due to the = rapid rise in temperature which in turn had an effect on the operation = of the pressure switch In my recent experience...after opening the dump = valve, the hydraulic pump did run, confirming continuity to the pump. = After working the nose gear into the locked position, the landing was = uneventful but I would like to avoid this uncomfortable situation in the = future. Would a tweak on the pressure switch adjustment be called for = here or just expect to momentarily crack open the dump valve to relieve = excess pressure. Thanks for your thoughts. William Ford N11LL ------=_NextPart_000_006E_01CF5A29.966600E0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
The problem is caused by the hudraulic = pump not=20 operating as desired. The shuttle valve inside it comes off its end stop = and=20 traps fluid in the lines. This trapped fluid expands with temperature = increase=20 increasing pressure in the lines and trips the pressure switches. Since = the=20 switches are now open, no electricity can get to the pump morot . . . = gear=20 failure.
 
There are three solutions to this=20 problem.
1) add an accumulator to the hydraulic=20 system.
2) rebuild and possibly modify the the = pump=20
3) install my electric module that = monitors the=20 pressure switches and automatically runs the pump to vent the offending=20 pressures.
 
Wolfgang
 
----- Original Message -----
From:=20 William=20 Ford
Sent: Wednesday, April 16, 2014 = 10:06=20 AM
Subject: Gear Down...INOP

I believe that I recently experienced something in my = Legacy that=20 I remember reading about but can't remember all the details.  I = looked=20 into the LML archives and was unsuccessful.  Could someone out = there=20 please briefly summarize the situation, reason and any possible = remedies for=20 gear extension failure following high altitude cruise in cold air = followed by=20 a decent and landing in hot air.  I seem to remember a discussion = about=20 boosted pressure in the hydraulics plumbing due to the rapid rise in=20 temperature which in turn had an effect on the operation of the = pressure=20 switch  In my recent experience...after opening the dump valve, = the=20 hydraulic pump did run, confirming continuity to the pump.  After = working=20 the nose gear into the locked position, the landing was uneventful but = I would=20 like to avoid this uncomfortable situation in the future.  Would = a tweak=20 on the pressure switch adjustment be called for here or just expect to = momentarily crack open the dump valve to relieve excess pressure. =  Thanks=20 for your thoughts.

William Ford
N11LL
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