Model "AE Fuel Guardian"

A Low  Fuel  Annunciation  System designed for Aircraft





1.) Install the annunciator lights & switch in your instrument panel.

A.) Drill two holes for the lights, (0.625" dia.).  The lights measure 0.705" x 0.95", and protrude 0.35".

B.)  Install the switch.  Drill a 0.275" dia. hole.

B.) Affix the proper low fuel quantity lettering.


     Right & Left Tank                         Instrument Panel Lettering


Lettering can be easily inserted in the light's lens!


2.) Install the electronics.

A.) The electronics enclosure measures 3.5" x 2.25 x 1.25".  Find an appropriate spot under the instrument panel and install the enclosure using two #6-32 screws.  The centers of the mounting screws are 3.625" apart.  Easy wiring instructions are included!



3. Find the proper location for the sensor.   

A.) Position your fuel tank in the approximate "level flight position".

B.) Temporarily attach a clear plastic hose to the fuel tank drain cock.

C.) Fill the tank (with WATER to be safe) to your pre-selected, low fuel alarm quantity.

D.) Position the hose so that the top of the liquid in the hose, is closest to your internal fuel tank pick-up point.

E.) Mark the location for your sensor, near the top of the liquid level in the hose.


          Location #1                                       An Alternate Location


(Coloring had been added to the water for photograph clarity)

This gentleman has chosen a 3.0 Gallon alarm level for his right tank.  It is exactly 20 minutes of flight left at 9.0 Gal/Hr.


4.) Install the optical sensors in your fuel tanks.

A.) Drill an appropriate diameter hole, and install the sensor.  A 0.475" dia. hole will suffice.

B.) Use Proseal (or an equivalent sealer) to further insure there are no fuel leaks.

      A 12mm nut (1.0 pitch) is used to secure the sensor in the tank.  The nut goes on the inside.


For those who cannot get into the fuel tank to secure the sensor nut, there is a work-around method that we can suggest.  Fabricate a bracket on the outside of the tank that will hold the sensor securely against the tank wall with an adequate amount of pressure.  Use the rubber gasket in between the sensor and the tank wall to help seal the fuel from leaking.  Do not rely on this bracket pressure alone to keep the tank from leaking.  Use Proseal to seal the sensor from the outside of the tank after your bracket is in place.  You may even put it in between the gasket, tank wall, and sensor to ensure a good seal.  If you choose to utilize this suggested method, it will be left to the builder/installer to ensure that this is a good method for your application.



        Appropriate hole diameter, 0.475"

        Sensor measures .75" across flats of nut on the outside of the tank

        The sensor protrudes into the tank approximately 0.775"

(Mount the sensor only horizontally, not vertically.  The reason for this is because you do not want to have any fluid drops on the end of the sensor when there is no liquid present.  This may give false readings. )



DO NOT put the sensor wires in any liquid, even for testing the system!  The wires are not totally liquid proof on the outside of the tank.  ONLY dip the tip of the sensor in liquid for testing the system.  Be sure not to scratch the tip of the sensor when handling it.


C.) Connect the sensor cables to the electronics.






(User supplied Proseal sealant not shown)