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In a message dated 1/14/1 10:48:13 PM, you wrote:

<<Might be useful to have a warning light on the panel come on when a sensor in a wing tank fuel line detects air in the line vs fuel. Do any of you know if something like this exists as well as a source for such a device?>>

YES!

Pillar Point Avionics now sells such a gizmo.  (www.ppavionics.com)  These are the guys that sell the "Smart Switch" for controlling Facet fuel transfer pumps.  Anyways, this new gizmo is a plastic (plexiglass? polycarbonate?  I dunno) tube that is pointed on the end like a drill bit.  An infrared light shines through the plastic towards the point.  If the point is submerged in fuel the light continues on through, but if the point is submerged in air (as it were) the principle of Total Internal Reflection causes the light to be reflected back.  A photodetector of some kind detects this.

The whole gizmo is tiny and is built into a 1/8 NPT to 1/4 NPT reducer fitting.  All you have to do is screw it into a 1/4 NPT tee fitting in your fuel line.  It's complete (not a kit) and sells for about $70.

- Rob

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Please send your photos and drawings to marvkaye@olsusa.com.