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Date: Tue, 19 May 2009 20:39:28 -0400
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Subject: RE: [LML] FL220 [and high speed taxi] fuel flow interruption
In-Reply-To: <list-3646387@logan.com>
Thread-Topic: [LML] FL220 [and high speed taxi] fuel flow interruption
Thread-Index: AcnYGrD6My4zSKNYSMewozHZBolvnwAAx7Mg
From: "Chuck Jensen" <cjensen@dts9000.com>

You're sure all vents are operating properly.  With full, or nearly full =
tanks, blocked vents will show up a lot faster than half, or nearly =
empty tanks.  Because each run up seem to be progressively worse, =
perhaps you were pulling against a vacuum in the tank(s). =20

Then when you opened things up and checked around, things seemed good =
again...of course, by then the vacuum in the tanks would have been =
neutralized.  Long shot but worth thinking about.

Chuck Jensen


-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of
William Miller
Sent: Monday, May 18, 2009 8:38 PM
To: lml@lancaironline.net
Subject: [LML] FL220 [and high speed taxi] fuel flow interruption


 Thanks for all the great response both on and off list.
Well, this morning I thought it was probably vapor lock between the fuel =
tank and the boost pump caused by the rapid assent after heat soaking in =
the hot summer sun.. There were several good threads on this which I =
found by searching "vapor lock" on lml.=20
 This afternoon while taxiing over to do the inspections I decided to do =
a series of full power runups down the runway. Initially, I noticed a =
reduced fuel flow around 26 gph, well below the 42 I usually see on =
takeoff. Oddly the power response and acceleration seemed normal but the =
fuel flow was low. This low reading of 26 vs 42 (normal) would have =
caused an aborted takeoff last Friday, so its new since the event at =
altitude. The first three runs, my data recorder did not record, so I =
went back for three more. On takeoff run number 4 I noticed a little =
roughness and fuel flow dropping to 22. On the 5th and last run just as =
I reached full throttle the engine suddenly quit completely.
 We towed it back, did another thorough look at gascolator, screen, =
lines, valve, everything. No foreign material visible anywhere. Mega =
fuel sump drains before and after show nothing on visual inspection. =
Nice blue color, no water, no grit. Disconnecting the fuel line we got =
solid flow on high boost at 44. Recowled and tried to redo it with my =
mechanic in the right seat. Now of course all is perfect. Good flow at =
42, good fuel pressure.
 I did capture the data earlier when it failed, but could not duplicate =
thereafter. Nothing seemed to change by switching tanks. We are =
consulting TCM in the morning. My mechanic is suggesting it might be =
fuel control related.
 I don't think its contaminated fuel, but this did all start about 30 =
min after refueling last Friday with a big load of 92 gal out of 108 =
capacity. I am thinking about that ferry adventure to Pango Pango and =
back to Hawaii. What would cause invisible contamnition?
 Several responders asked for an  update, so I will keep you posted. You =
all gave us several good places to look, but I don't want to make this =
post  too long by detailing all the things we ruled out.
This is an awesome safety resource! Thanks to all for the support.

It is a riddle, wrapped in a mystery, inside an enigma...
Bill Miller

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