X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 19 Jun 2009 12:21:57 -0400 Message-ID: X-Original-Return-Path: Received: from imo-d22.mx.aol.com ([205.188.144.208] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3688256 for lml@lancaironline.net; Fri, 19 Jun 2009 10:39:32 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.144.208; envelope-from=VTAILJEFF@aol.com Received: from imo-ma01.mx.aol.com (imo-ma01.mx.aol.com [64.12.78.136]) by imo-d22.mx.aol.com (v107.10) with ESMTP id RELAYIN2-34a3ba2f03b9; Fri, 19 Jun 2009 10:38:40 -0400 Received: from VTAILJEFF@aol.com by imo-ma01.mx.aol.com (mail_out_v40_r1.5.) id q.bbe.4ebfa132 (34920) for ; Fri, 19 Jun 2009 10:38:37 -0400 (EDT) Received: from smtprly-ma01.mx.aol.com (smtprly-ma01.mx.aol.com [64.12.207.140]) by cia-da03.mx.aol.com (v124.15) with ESMTP id MAILCIADA035-5c4a4a3ba2d7141; Fri, 19 Jun 2009 10:38:30 -0400 Received: from webmail-db11 (webmail-db11.webmail.aol.com [205.188.105.76]) by smtprly-ma01.mx.aol.com (v124.15) with ESMTP id MAILSMTPRLYMA018-5c4a4a3ba2d7141; Fri, 19 Jun 2009 10:38:15 -0400 References: X-Original-To: lml@lancaironline.net Subject: Re: [LML] Re: Boost pump question X-Original-Date: Fri, 19 Jun 2009 10:38:15 -0400 X-AOL-IP: 64.12.78.136 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: vtailjeff@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CBBF02B6BBE2AC_1394_277E_webmail-db11.sysops.aol.com" X-Mailer: AOL Webmail 43524-STANDARD Received: from 66.220.104.170 by webmail-db11.sysops.aol.com (205.188.105.76) with HTTP (WebMailUI); Fri, 19 Jun 2009 10:38:15 -0400 X-Original-Message-Id: <8CBBF02B619C34C-1394-1302@webmail-db11.sysops.aol.com> X-Spam-Flag:NO ----------MB_8CBBF02B6BBE2AC_1394_277E_webmail-db11.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" I have tried this at altiude and have not had the engine quit-- seems like= =C2=A0a urban legend. Jeff But, if HIGH was selected with the mechanical, it could produce very high= flows and kill the engine so the MEB advised leaning to prevent such an= occurrence -----Original Message----- From: paul miller To: lml@lancaironline.net Sent: Thu, Jun 18, 2009 8:28 pm Subject: [LML] Re: Boost pump question That's a really interesting design philosophy being used by Cessna now.=C2= =A0=C2=A0 In the Multiengine Cessnas (I put 3000+ hours in my C414A) the= same setup was originally installed and it killed a few people.=C2=A0 Man= datory SB 88-3 required a change to LOW-OFF-HIGH switch by requiring the= pilot to manually select HIGH and it was interlocked on the high side lik= e the Columbia.=C2=A0=C2=A0=C2=A0 It turns out that the sensing switches= and wiring were less reliable than the engine or mechanical fuel pumps th= ey were supposed to protect. Glitches and failures in the sensing system= triggered HIGH setting which combined with mechanical fuel pump pressure= would kill an engine in the multis.=C2=A0 The bottom line was that manual= selection of the high setting was deemed best practice by Cessna in 1988= in multiengine pistons.=C2=A0=C2=A0 In addition, HIGH would not sustain= full power alone so MP had to be managed to meet fuel flow.=C2=A0 But, if= HIGH was selected with the mechanical, it could produce very high flows= and kill the engine so the MEB advised leaning to prevent such an occurre= nce. Perhaps th e sensing is now better or perhaps there has not been a repeat of the prob= lems that led to changing out that design but the whole issue of auto HIGH= fuel pump can really throw you for a loop if it comes into play at the wr= ong time and you haven't selected it manually.=C2=A0 It's worth thinking= about how you would deal with an Auto HIGH kicking in properly or imprope= rly. Paul Miller N357V Legacy N700CS TBM700A Richard T. Schaefer wrote: Dan, =C2=A0 My understanding (from reading the Columbia 400 manual) is that the= Low mode is used for vapor suppression above 10,000 ft. =C2=A0 The High is used when the mechanical pump fails, during prime, and= prior to a hot start to cool any heat soaked components in the fuel syste= m (as the hot excess fuel is returned to your fuel tank). =C2=A0 =C2=A0 When you setup your fuel system for your engine you should verify= that high fuel pump mode will not flood your engine. =C2=A0 =C2=A0 In the Columbia (as I understand) the prime button engages the high= fuel mode. =C2=A0 They have a three way switch, LOW, OFF, and HIGH arm. =C2=A0 The HIGH arm uses a fuel pressure switch and locking relay. The int= ent is if the fuel pressure drops while on HIGH arm, the HIGH mode of the= fuel pump is engaged and is locked in, even as the fuel pressure rises as= a result of the pump coming on. =C2=A0 =C2=A0The HIGH arm is used during climb and cruise below 10,000 ft= and set to OFF during descent. (And of course the LOW is used always above 10,000 ft). =C2=A0=C2=A0 I assume you would go to HIGH arm on a go-around =E2=80=A6 on= e more thing to the checklist during a busy time. =C2=A0 =C2=A0=C2=A0 It=E2=80=99s important to make sure that HIGH and LOW are not= engaged at the same time. So there is some care to how the primer button= interacts with the three way switch. =C2=A0 =C2=A0 This is how I am setting up my IV-P. =C2=A0 r.t.s. =C2=A0 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Dan= Reagan Sent: Thursday, June 18, 2009 8:09 AM To: lml@lancaironline.net Subject: [LML] Boost pump question =C2=A0 Since my crankshaft bolt problem is causing me to change out my engine, I= have decided to change from my current FADEC engine to a conventional mix= ture control engine.=C2=A0 The boost pump I currently have is a 2 speed Du= kes and in the past was turned on and off by FADEC. (It could be manually= turned on as when above 10,000 feet)=C2=A0 =C2=A0 My question is, when I am rewiring the fuel pump, do I need both the high= and the low speeds?=C2=A0 My dumb question of the day is,=C2=A0when is th= e fuel pump supposed to be used on the TSIO550 in the Lancair IVP? =C2=A0 Dan Reagan IVP 650 hours ----------MB_8CBBF02B6BBE2AC_1394_277E_webmail-db11.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" I have tried this at altiude and have not had the engine quit-- seems like=  a urban legend.

Jeff
But,= if HIGH was selected with the mechanical, it could produce very high flow= s and kill the engine so the MEB advised leaning to prevent such an occurr= ence



-----Original Message-----
From: paul miller <paul@tbm700.com>
To: lml@lancaironline.net
Sent: Thu, Jun 18, 2009 8:28 pm
Subject: [LML] Re: Boost pump question

That's a reall= y interesting design philosophy being used by Cessna now.   In= the Multiengine Cessnas (I put 3000+ hours in my C414A) the same setup wa= s originally installed and it killed a few people.  Mandatory SB 88-3= required a change to LOW-OFF-HIGH switch by requiring the pilot to manual= ly select HIGH and it was interlocked on the high side like the Columbia.&= nbsp;   It turns out that the sensing switches and wiring were= less reliable than the engine or mechanical fuel pumps they were supposed= to protect. Glitches and failures in the sensing system triggered HIGH se= tting which combined with mechanical fuel pump pressure would kill an engi= ne in the multis.  The bottom line was that manual selection of the= high setting was deemed best practice by Cessna in 1988 in multiengine pi= stons.   In addition, HIGH would not sustain full power alone so= MP had to be managed to meet fuel flow.  But, if H IGH was selected with the mechanical, it could produce very high flows and= kill the engine so the MEB advised leaning to prevent such an occurrence.=

Perhaps the sensing is now better or perhaps there has not been a repeat= of the problems that led to changing out that design but the whole issue= of auto HIGH fuel pump can really throw you for a loop if it comes into= play at the wrong time and you haven't selected it manually.  It's= worth thinking about how you would deal with an Auto HIGH kicking in prop= erly or improperly.

Paul Miller
N357V Legacy
N700CS TBM700A

Richard T. Schaefer wrote:
Dan,<= /div>
  My understan= ding (from reading the Columbia 400 manual) is that the Low mode is used= for vapor suppression above 10,000 ft.
  The High is= used when the mechanical pump fails, during prime, and prior to a hot sta= rt to cool any heat soaked components in the fuel system (as the hot exces= s fuel is returned to your fuel tank).
 
  When you set= up your fuel system for your engine you should verify that high fuel pump= mode will not flood your engine.
 
  In the Colum= bia (as I understand) the prime butto n engages the high fuel mode.
  They have a= three way switch, LOW, OFF, and HIGH arm.
  The HIGH arm= uses a fuel pressure switch and locking relay. The intent is if the fuel= pressure drops while on HIGH arm, the HIGH mode of the fuel pump is engag= ed and is locked in, even as the fuel pressure rises as a result of the pu= mp coming on.
   The HI= GH arm is used during climb and cruise below 10,000 ft and set to OFF duri= ng descent. (And of course the LOW is used always above 10,000 ft).=
   I assu= me you would go to HIGH arm on a go-around =E2=80=A6 one more thing to the= checklist during a busy time.
 
   It=E2= =80=99s important to make sure that HIGH and LOW are not engaged at the same time. So there is some care to how the primer button= interacts with the three way switch.
 
  This is how= I am setting up my IV-P.
 
r.t.s.
 
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Dan Reagan
Sent: Thursday, June 18,= 2009 8:09 AM
To: lml@lancaironline.net<= /A>
Subject: [LML] Boost pump= question
 
Since my crankshaft bolt problem is causing= me to change out my engine, I have decided to change from my current FADE= C engine to a conventional mixture control engine.  The boost pump I= currently have is a 2 speed Dukes and in the past was turned on and off= by FADEC. (It could be manually turned on as when above 10,000 feet) = ;
 
My question is, when I am rewiring the fuel= pump, do I need both the high and the low speeds?  My dumb question= of the day is, when is the fuel pump supposed to be used on the TSIO= 550 in the Lancair IVP?
 
Dan Reagan
IVP 650 hours
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