X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 21 Jun 2009 20:29:49 -0400 Message-ID: X-Original-Return-Path: Received: from betsy.gendns5.com ([65.254.38.234] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with ESMTPS id 3688724 for lml@lancaironline.net; Fri, 19 Jun 2009 15:31:07 -0400 Received-SPF: none receiver=logan.com; client-ip=65.254.38.234; envelope-from=paul@tbm700.com Received: from adsl-35-179-137.dab.bellsouth.net ([67.35.179.137]:54367 helo=[192.168.1.120]) by betsy.gendns5.com with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.69) (envelope-from ) id 1MHjn9-0006JV-J6 for lml@lancaironline.net; Fri, 19 Jun 2009 15:30:29 -0400 X-Original-Message-Id: From: paul miller X-Original-To: "Lancair Mailing List" In-Reply-To: Content-Type: multipart/alternative; boundary=Apple-Mail-35-844655921 Mime-Version: 1.0 (Apple Message framework v935.3) Subject: Re: [LML] Re: Boost pump question X-Original-Date: Fri, 19 Jun 2009 15:30:28 -0400 References: X-Mailer: Apple Mail (2.935.3) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - betsy.gendns5.com X-AntiAbuse: Original Domain - lancaironline.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tbm700.com --Apple-Mail-35-844655921 Content-Type: text/plain; charset=WINDOWS-1252; format=flowed; delsp=yes Content-Transfer-Encoding: quoted-printable You may be right but Cessna does believe it to be a risk, if not =20 proven already. The AFM supplement incorporating MEB 88-3 included =20 the following cautionary note: "If the auxiliary fuel pump switches are placed in the HIGH position =20 with the engine-driven fuel pump(s) operating normally, total loss of =20= engine 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 =20= > high flows and kill the engine so the MEB advised leaning to prevent =20= > 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 =20 > now. In the Multiengine Cessnas (I put 3000+ hours in my C414A) =20 > the same setup was originally installed and it killed a few people. =20= > Mandatory SB 88-3 required a change to LOW-OFF-HIGH switch by =20 > requiring the pilot to manually select HIGH and it was interlocked =20 > on the high side like the Columbia. It turns out that the sensing =20= > switches and wiring were less reliable than the engine or mechanical =20= > fuel pumps they were supposed to protect. Glitches and failures in =20 > the sensing system triggered HIGH setting which combined with =20 > mechanical fuel pump pressure would kill an engine in the multis. =20 > The bottom line was that manual selection of the high setting was =20 > deemed best practice by Cessna in 1988 in multiengine pistons. In =20= > addition, HIGH would not sustain full power alone so MP had to be =20 > managed to meet fuel flow. But, if HIGH was selected with the =20 > mechanical, it could produce very high flows and kill the engine so =20= > the MEB advised leaning to prevent such an occurrence. > > Perhaps the sensing is now better or perhaps there has not been a =20 > repeat of the problems that led to changing out that design but the =20= > whole issue of auto HIGH fuel pump can really throw you for a loop =20 > if it comes into play at the wrong time and you haven't selected it =20= > manually. It's worth thinking about how you would deal with an Auto =20= > HIGH kicking in properly or improperly. > > Paul Miller > N357V Legacy > N700CS TBM700A > > Richard T. Schaefer wrote: >> >> 0A >> Dan, >> My understanding (from reading the Columbia 400 manual) is that =20 >> the Low mode is used for vapor suppression above 10,000 ft. >> The High is used when the mechanical pump fails, during prime, =20 >> and prior to a hot start to cool any heat soaked components in the =20= >> fuel system (as the hot excess fuel is returned to your fuel tank). >> >> When you setup your fuel system for your engine you should verify =20= >> that high fuel pump mode will not flood your engine. >> >> In the Columbia (as I understand) the prime button engages the =20 >> high fuel mode. >> 0D >> They have a three way switch, LOW, OFF, and HIGH arm. >> The HIGH arm uses a fuel pressure switch and locking relay. The =20 >> intent is if the fuel pressure drops while on HIGH arm, the HIGH =20 >> mode of the fuel pump is engaged and is locked in, even as the fuel =20= >> pressure rises as a result of the pump coming on. >> The HIGH arm is used during climb and cruise below 10,000 ft and =20= >> set to OFF during descent. (And of course the LOW is used always =20 >> above 10,000 ft). >> I assume you would go to HIGH arm on a go-around =85 one more =20 >> thing to the checklist during a busy time. >> >> It=92s important to make sure that HIGH and LOW are not engaged at = =20 >> the same time. So there is some=3D2 0care to how the primer button =20= >> 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 =20= >> Of Dan Reagan >> Sent: Thursday, June 18, 2009 8:09 AM >> To: < A class=3Dmoz-txt-link-abbreviated = href=3D"mailto:lml@lancaironline.net=20 >> ">lml@lancaironline.net >> Subject: [LML] Boost pump question >> >> Since my crankshaft bolt problem is causing me to change out my =20 >> engine, I have decided to change from my current FADEC engine to a =20= >> conventional mixture control engine. The boost pump I currently =20 >> have is a 2 speed Dukes and in the past was turned on and off by =20 >> 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 =20 >> the high and the low speeds? My dumb question of the day is, when =20= >> is the fuel pump supposed to be used on the TSIO550 in the Lancair =20= >> IVP? >> >> Dan Reagan >> IVP 650 hours > > > Make your summer sizzle with fast and easy recipes for the grill. --Apple-Mail-35-844655921 Content-Type: text/html; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable You may be right but Cessna = does believe it to be a risk, if not proven already.  The AFM = supplement incorporating MEB 88-3 included the following cautionary = 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, 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 <paul@tbm700.com>
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.   In = the Multiengine Cessnas (I put 3000+ hours in my C414A) the same setup = was 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 = manually select HIGH and it was interlocked on the high side like the = Columbia.    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 setting which combined with mechanical fuel pump pressure = would kill an engine in the multis.  The bottom line was that = manual selection of the high setting was deemed best practice by Cessna = in 1988 in multiengine pistons.   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 thinking about how = you would deal with an Auto HIGH kicking in properly or = improperly.

Paul Miller
N357V Legacy
N700CS = TBM700A

Richard T. Schaefer wrote:
0A
Dan,
  My understanding (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 start to = cool any heat soaked components in the fuel system (as the hot excess = fuel is returned to your fuel tank).
  When you setup your fuel system for your = engine you should verify that high fuel pump mode will not flood your = engine.
 
  In the Columbia (as I = understand) the prime button engages the high fuel = mode.
0D
  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 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 set to OFF during descent. (And of course the = LOW is used always above 10,000 ft).
   It=92s 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 interacts with the three way = switch.
 
  This is how I am = setting up my IV-P.
 
 
 
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 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 = TSIO550 in the Lancair IVP?
 
Dan = Reagan
IVP 650 = hours

Make your summer sizzle = with fast = and easy recipes for= the grill.

= --Apple-Mail-35-844655921--