X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 23 Aug 2005 09:44:51 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d20.mx.aol.com ([205.188.139.136] verified) by logan.com (CommuniGate Pro SMTP 5.0c1) with ESMTP id 678204 for lml@lancaironline.net; Mon, 22 Aug 2005 16:58:49 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.139.136; envelope-from=Sky2high@aol.com Received: from Sky2high@aol.com by imo-d20.mx.aol.com (mail_out_v38_r4.1.) id q.d8.2baf8fa1 (3310) for ; Mon, 22 Aug 2005 16:57:53 -0400 (EDT) From: Sky2high@aol.com X-Original-Message-ID: X-Original-Date: Mon, 22 Aug 2005 16:57:52 EDT Subject: Re: [LML] Re: bad gear switch? X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1124744272" X-Mailer: 9.0 Security Edition for Windows sub 5009 X-Spam-Flag: NO -------------------------------1124744272 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 8/22/2005 2:22:44 P.M. Central Standard Time, sportform@cox.net writes: > When this happens in flight have you just tried to momentarily crack > open the dump valve and return it to the closed position to relieve > the possible back pressure while the gear switch is in the down > position? No, it was drilled into my head during training that you only have one shot with the dump...I followed the procedure. > > When the pump is running does your "gear in transition" light come > on? If so, when you opened the dump valve (assuming you did not pull > the breakers) did the light come on? Now that you mention it, no, it does not. One of those pesky little things you notice but then forget to ask about....how do I fix that? There are definitely disadvantages to not building your own airplane...but I have you guys to help - which is what makes this list so great! Any input is welcome... Barry, The "dump valve" only cross connects the hi and lo pressure sides of the hydraulic system. Its purpose is to relieve any hydraulic pressure and allow the gear to drop in case of a system failure - a failure could be a bad pump, a stuck relay, a bad pressure switch, no power at all, no fluid at all, etc. If you cannot get your gear down, then a check list could be as follows (mine is posted on the panel): Slow to 87 KIAS Gear Sw to Down Motor (and relay) Breakers Out Dump Valve Open Gear Locked Lights On Of course, one may need to do some slips to insure the mains are locked or pull some G's to get the nose gear locked if the gas spring is weak. See, that's why you should check the emergency operation every month. Your training and the procedure was in error, it is not a "one shot" deal - If it were, you would only frightfully test the emergency gear extension over the field and then proceed to land with no hydraulic pressure ensuring that the over-center links are held in place by something other than the emergency backup springs. Anyway, after the gear is down and locked, add back some power, close the dump valve and restore the breaker(s) - the pump should run for a bit to build pressure. Now retract the gear and continue your fun flight for the day after practicing other slow flight maneuvers. Finally, open the throttle and swiftly move thru the air. Of course, your transition light is probably the un-testable kind from Lancair. If I were making recommendations, I would suggest using the old fashioned (and expensive) push-to-test lights. These are also useful for the gear locked lights too since it could cause one to have a sweaty upper lip if the bulb was out but the gear was actually locked. Since we are in modern times, maybe someone would design circuitry using LEDs with a test function......... You said: One of those pesky little things you notice but then forget to ask about....how do I fix that? Uhhhhh, nothing in aviation fixes itself (a rule I learned shortly after taking flying lesson in rented aircraft). Maybe the bulb is burned out, maybe the wire is burned out, maybe..... Check the wiring diagram, it is in your POH ---- You were supplied with a POH weren't you? If not, use the diagram I e-mailed a few days ago. BTW, I hope the intermittent relay that kept your pump running wasn't damaged by being selected for the time it took to land and taxi in. Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) -------------------------------1124744272 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 8/22/2005 2:22:44 P.M. Central Standard Time,=20 sportform@cox.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>>=20 When this happens in flight have you just tried to momentarily crack
&= gt;=20 open the dump valve and return it to the closed position to relieve
&g= t;=20 the possible back pressure while the gear switch is in the down
>=20 position? 

No, it was drilled into my head during training tha= t=20 you only have one
shot with the dump...I followed the=20 procedure.

>  
> When the pump is running does your "= gear=20 in transition" light come
> on?  If so, when you opened the du= mp=20 valve (assuming you did not pull
> the breakers) did the light come= =20 on?

Now that you mention it, no, it does not.  One of those pe= sky=20 little
things you notice but then forget to ask about....how do I fix=20 that?

There are definitely disadvantages to not building your own=20
airplane...but I have you guys to help - which is what makes this list= =20
so great!  Any input is welcome...
Barry,
 
The "dump valve" only cross connects the hi and lo pressure sides of th= e=20 hydraulic system.  Its purpose is to relieve any hydraulic pressure=20 and allow the gear to drop in case of a system failure - a=20 failure could be a bad pump, a stuck relay, a bad pressure=20 switch, no power at all, no fluid at all, etc.   If you cannot get= =20 your gear down, then a check list could be as follows (mine is posted o= n=20 the panel):
 
Slow to 87 KIAS
Gear Sw to Down
Motor (and relay) Breakers Out
Dump Valve Open
Gear Locked Lights On
 
Of course, one may need to do some slips to insure the mains are=20 locked or pull some G's to get the nose gear locked if the gas spring is=20 weak.  See, that's why you should check the emergency operation every=20 month.  Your training and the procedure was in error, it is n= ot a=20 "one shot" deal - If it were, you would only frightfully test the emerg= ency=20 gear extension over the field and then proceed to land with no hydraulic=20 pressure ensuring that the over-center links are held in place by something=20 other than the emergency backup springs.  Anyway, after the gear is dow= n=20 and locked, add back some power, close the dump valve and restore the breake= r(s)=20 - the pump should run for a bit to build pressure.  Now retract the gea= r=20 and continue your fun flight for the day after practicing other slow flight=20 maneuvers.  Finally, open the throttle and swiftly move thru the air.
 
Of course, your transition light is probably the un-testable kind=20= from=20 Lancair.  If I were making recommendations, I would suggest using the o= ld=20 fashioned (and expensive) push-to-test lights.  These are also useful f= or=20 the gear locked lights too since it could cause one to have a sweaty upper l= ip=20 if the bulb was out but the gear was actually locked.  Since=20= we=20 are in modern times, maybe someone would design circuitry using LEDs with a=20= test=20 function......... 
 
You said:
One of those pesky little
things you notice but then forget to ask=20 about....how do I fix that?
Uhhhhh, nothing in aviation fixes itself (a rule I learned shortly afte= r=20 taking flying lesson in rented aircraft).
 
Maybe the bulb is burned out, maybe the wire is burned out,=20 maybe.....
 
Check the wiring diagram, it is in your POH ---- You were supplied with= a=20 POH weren't you?  If not, use the diagram I e-mailed a few days=20 ago.
 
BTW, I hope the intermittent relay that kept your pump running wasn't=20 damaged by being selected for the time it took to land and taxi in.=20
 
Scott Krueger=20 AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)



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