Fuel Consumption: Cessna Indicator Vs. Shadin

[Bob Cook]

Jose

The cessna fuel flow indicator is based on FUEL PRESSURE to sense fuel flow.

The shadin uses a DIGITAL flow sensor (much like a miniature paddle wheel in the fuel "stream". It is located post fuel control unit.

Each sensor is different in that the calibration (flow rate) varies from unit to unit. The calibration is recorded on the side of the fuel sensor and this number needs to be inserted into the computer for calibration to be accurate. Basically it is the number of turns of the paddle wheel / unit of volume (fuel). If you give Shadin the serial number of the sensor they can tell you the calibration or correction required.

It is best to accurately record your fuel usage after a long trip and apply a correction if accuracy is CONSISTANTLY out. I find my accuracy to be within about 1 gallon per 140 gallons or less than one percent. In fact, I no longer have the Cessna flow rate indicators.

Probably a sensor was replaced in the past without applying the correction required and thus the difference in readings.

hope this helps

Bob