X-Virus-Scanned: clean according to Sophos on Logan.com X-SpamCatcher-Score: 2 [X] Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 26 Feb 2007 20:19:26 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m21.mx.aol.com ([64.12.137.2] verified) by logan.com (CommuniGate Pro SMTP 5.1.7) with ESMTP id 1870264 for lml@lancaironline.net; Mon, 26 Feb 2007 19:59:40 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.2; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-m21.mx.aol.com (mail_out_v38_r7.6.) id q.d07.9fa1fe3 (42805) for ; Mon, 26 Feb 2007 19:58:41 -0500 (EST) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Mon, 26 Feb 2007 19:58:41 EST Subject: Re: [LML] 360 gear door closes before gear retracts X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1172537921" X-Mailer: 9.0 Security Edition for Windows sub 5358 X-Spam-Flag: NO -------------------------------1172537921 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 2/26/2007 5:56:40 P.M. Central Standard Time, kneadedpleasures@sbcglobal.net writes: Don't think I caused this problem but I certainly have to deal with it - gear door closed before gear retracted in flight - no accident but could have been if the gear had strongly jammed into retract such that low pressure on extension might not have been sufficient to permit extension; possible prop strike. Didn't know of this condition until I was safely on the ground - didn't use the emergency gear extension - nor did I flip the gear-pressure-release valve - don't think I changed anything from the careful routines that I have used in dozens of previous flights. So what might have caused this scenario? What must be done to prevent it in the future (besides "not flying")? Thanks for your comments. Greg, You have not provided enough information. Main or Nose? Ow, the nose gear door would be messy while the mains would probably remain not up tight. Here is one possibility: 1. Gear retraction is initiated. It is usual to see mains start up until there is enough pressure the start the nose over center link (held in place by the 100# gas spring). 2. At this pulse of high pressure, enough to start the over center link to move, one of the sequence valves fail and high pressure is supplied to a door. 3. Since the door spring is weak, it closes while the system is overcoming the strong nose gear gas spring. 4. The retract sequence is completed - I.E. the pressure builds high enough to turn off the pump. Note that the sequence valve is only a check valve that is defeated when the plunger is depressed. Oh, that leads to a second scenario just as possible. To wit: 1. On extension, the sequences valve is stuck in the "plunger pushed in" condition (maybe the plunger is dirty or bent). 2. Extension only pressurizes the down side, making the check valve against up pressure irrelevant. 3. With the sequence valve "stuck", retract causes the door to close early as in the first possibility. Let us know what your analysis. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) Darwinian culling phrase: Watch This!


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In a message dated 2/26/2007 5:56:40 P.M. Central Standard Time,=20 kneadedpleasures@sbcglobal.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>
Don't think I caused this problem but I certainly have to deal with i= t -=20 gear door closed before gear retracted in flight - no accident but co= uld=20 have been if the gear had strongly jammed into retract such that low press= ure=20 on extension might not have been sufficient to permit extension; possible=20= prop=20 strike. 
 
Didn't know of this condition until I was safely on the ground - didn= 't=20 use the emergency gear extension - nor did I flip the gear-pressure-releas= e=20 valve - don't think I changed anything from the careful routines that I ha= ve=20 used in dozens of previous flights.  So what might have caused this=20 scenario?  What must be done to prevent it in the future (besides "no= t=20 flying")?  Thanks for your comments.
Greg,
 
You have not provided enough information.  Main or Nose?  Ow,= the=20 nose gear door would be messy while the mains would probably remain not up=20 tight.
 
Here is one possibility:
1. Gear retraction is initiated.  It is usual to see mains start u= p=20 until there is enough pressure the start the nose over center link (hel= d in=20 place by the 100# gas spring).
2. At this pulse of high pressure, enough to start the over=20 center link to move, one of the sequence valves fail and high pressure is=20 supplied to a door.
3. Since the door spring is weak, it closes while the system is overcom= ing=20 the strong nose gear gas spring.
4. The retract sequence is completed - I.E. the pressure builds high en= ough=20 to turn off the pump.
 
Note that the sequence valve is only a check valve that is defeated whe= n=20 the plunger is depressed.  Oh, that leads to a second scenario just as=20 possible.  To wit:
1. On extension, the sequences valve is stuck in the "plunger pushed in= "=20 condition (maybe the plunger is dirty or bent).
2. Extension only pressurizes the down side, making the check valve aga= inst=20 up pressure irrelevant.
3. With the sequence valve "stuck", retract causes the door to close=20 early as in the first possibility.
 
Let us know what your analysis.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

Darwinian culling phrase: Watch=20 This!



AO= L now offers free email to everyone. Find out more about what's free from A= OL at AOL.com. -------------------------------1172537921--