X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Wed, 24 Jun 2009 07:44:29 -0400 Message-ID: X-Original-Return-Path: Received: from imr-d04.mx.aol.com ([205.188.157.42] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTP id 3700708 for lml@lancaironline.net; Tue, 23 Jun 2009 10:19:05 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.157.42; envelope-from=VTAILJEFF@aol.com Received: from imo-da03.mx.aol.com (imo-da03.mx.aol.com [205.188.169.201]) by imr-d04.mx.aol.com (v107.10) with ESMTP id RELAYIN1-24a40e41ad9; Tue, 23 Jun 2009 10:18:02 -0400 Received: from VTAILJEFF@aol.com by imo-da03.mx.aol.com (mail_out_v40_r1.5.) id q.d0b.4f5760ce (34916) for ; Tue, 23 Jun 2009 10:17:58 -0400 (EDT) Received: from smtprly-dc03.mx.aol.com (smtprly-dc03.mx.aol.com [205.188.170.3]) by cia-da03.mx.aol.com (v124.15) with ESMTP id MAILCIADA031-d3bf4a40e40f181; Tue, 23 Jun 2009 10:17:56 -0400 Received: from WEBMAIL-MZ07 (webmail-mz07.sim.aol.com [64.12.222.38]) by smtprly-dc03.mx.aol.com (v124.15) with ESMTP id MAILSMTPRLYDC037-d3bf4a40e40f181; Tue, 23 Jun 2009 10:17:51 -0400 References: X-Original-To: lml@lancaironline.net Subject: Re: [LML] Re: Boost pump question X-Original-Date: Tue, 23 Jun 2009 10:17:51 -0400 X-AOL-IP: 205.188.169.201 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_8CBC2248707444A_908_5E89_WEBMAIL-MZ07.sysops.aol.com" X-Mailer: AOL Webmail 43524-STANDARD Received: from 76.232.226.219 by WEBMAIL-MZ07.sysops.aol.com (64.12.222.38) with HTTP (WebMailUI); Tue, 23 Jun 2009 10:17:51 -0400 X-Original-Message-Id: <8CBC22486A0C003-908-2E02@WEBMAIL-MZ07.sysops.aol.com> X-Spam-Flag:NO ----------MB_8CBC2248707444A_908_5E89_WEBMAIL-MZ07.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Paul, I have worked a number of accidents allegedly caused by too much fuel floo= ding the engine and I have to wonder what the fuel flow guage and mixture= knob are for. Jeff -----Original Message----- From: paul miller To: lml@lancaironline.net Sent: Sun, Jun 21, 2009 7:29 pm Subject: [LML] Re: Boost pump question You may be right but Cessna does believe it to be a risk, if not proven al= ready. =C2=A0The AFM supplement incorporating=C2=A0MEB 88-3 included the= following cautionary note:=C2=A0 "If the auxiliary fuel pump switches are placed in the HIGH position with= the engine-driven fuel=C2=A0pump(s) operating normally, total loss of eng= ine power may occur." On 19-Jun-09, at 12:21 PM, vtailjeff@aol.com wrote: I do not believe this to be true-- I have selected HIGH at 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:=C2=A0lml@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 It turns out that the sensing switches and wiring were less reliabl= e than the engine or mechanical fuel pumps they 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 setti= ng 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 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.=C2=A0 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: 0A 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).0A =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. 0D =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 abov= e 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=3D2 0care to how the primer bu= tton 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:=C2=A0Lancair Mailing List [mailto:lml@lancaironline.net]=C2=A0On Beh= alf Of=C2=A0Dan Reagan Sent:=C2=A0Thursday, June 18, 2009 8:09 AM To:=C2=A0< A class=3Dmoz-txt-link-abbreviated href=3D"mailto:lml@lancairon= line.net">lml@lancaironline.net Subject:=C2=A0[LML] Boost pump question =C2=A0 Since my crankshaft bolt problem is causing me to change out my engine, I= have decided to change f rom my current FADEC engine to a conventional mixture control engine.=C2= =A0 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)=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 Make your summer sizzle with=C2=A0fast and easy recipes=C2=A0for the grill= . =3D ----------MB_8CBC2248707444A_908_5E89_WEBMAIL-MZ07.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" Paul,

I have worked a number of accidents allegedly caused by too much fuel floo= ding the engine and I have to wonder what the fuel flow guage and mixture= knob are for.

Jeff

-----Original Message-----
From: paul miller <paul@tbm700.com>
To: lml@lancaironline.net
Sent: Sun, Jun 21, 2009 7:29 pm
Subject: [LML] Re: Boost pump question

You may be rig= ht but Cessna does believe it to be a risk, if not proven already.  T= he AFM supplement incorporating MEB 88-3 included the following cauti= onary note: 
"If the auxiliary fuel pump switches are placed in the HIGH position= with the engine-driven fuel pump(s) operating normally, total loss= of engine power may occur."


On 19-Jun-09, at 12:21 PM, vtail= jeff@aol.com wrote:

I do not believe this to be true-- I have selected HIGH at
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 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.

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 thinkin g about how you would deal with an Auto HIGH kicking in properly or improp= erly.

Paul Miller
N357V Legacy
N700CS TBM700A

Richard T. Schaefer wrote:
0A
Dan,
  My unde= rstanding (from reading the Columbia 400 manual) is that the Low mode is= used for vapor suppression above 10,000 ft.
  The Hig= h is used when the mechanical pump fails, during prime, and prior to a hot= start to cool any heat soaked components in the fuel system (as the hot= excess fuel is returned to your fuel tank).
 <= /FONT>
  When= you setup your fuel system for your engine you should verify that high fu= el pump mode will not flood your engine.
 <= /FONT>
  In the= Columbia (as I understand) the prime button engages the high fuel mode.
0D
  They ha= ve a three way switch, LOW, OFF, and HIGH arm.
  The HIG= H 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= engaged and is locked in, even as the fuel pressure rises as a result of= the pump coming on.
 =  The HIGH arm is used during climb and cruise below 10,000 ft and se= t to OFF during descent. (And of course the LOW is used always above 10,00= 0 ft).
  = I assume you would go to HIGH arm on a go-around =E2=80=A6 one more thing= to the checklist during a busy time.
 <= /FONT>
  = It=E2=80=99s important to make sure that HIGH and LOW are not engaged at= the same time. So there is some=3D2 0care to how the primer button intera= cts with the three way switch.
 <= /FONT>
  This= is how I am setting up my IV-P.
 <= /FONT>
r.t.s.<= /FONT>
 <= /FONT>
From: Lancair Ma= iling List [m ailto:lml@lancaironline.net] = On Behalf Of Dan Reagan
Sent: Thursday, June 18, 2009 8:09 AM
To: < A class=3Dmoz-txt-link-abbreviated href=3D"= mailto:lml@lancaironline.net">l= ml@lancaironline.net
Subject: [LML] Boost pump question
 
Since my crankshaft bolt problem is caus= ing me to change out my engine, I have decided to change from my current= FADEC engine to a conventional mixture control engine.  The boost pu= mp 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)&= nbsp;
=  
My question is, when I am rewiring the= fuel pump, do I need both the high and the low speeds?  My dumb ques= tion of the day is, when is the fuel pump supposed to be used on the= TSIO550 in the Lancair IVP?
 
Dan Reagan
IVP 650 hours

=3D

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