Fuel Level Calibration

Tonym81

RV-9A
Joined
Aug 26, 2014
Messages
2
I just purchased a completed RV-9 and noticed the fuel level indicators show 14gallons each tank instead of 18 each tank. I checked the fuel computations and the preset and full fuel settings are set to 36. Is it ok to change the level without doing a complete recalibration?
 

jakej

Well-Known Member
Joined
Oct 10, 2007
Messages
2,150
Location
Adelaide, Australia
I may be incorrect here but I think you are talking about 2 different systems here
1. Fuel level - the standard float senders will not show all the fuel in the tank as it is unable to measure the top 5 gals or so.
2. Fuel Computer - this does not show level it should show TOTAL capacity of all tanks when full, however you can have a preset amount ie an amount that you'd use most of the time when not needing to completely fill the tanks.
Hopefully this answers your question  :)

Jake J
 

Dynon

Dynon Staff
Staff member
Joined
Jan 14, 2013
Messages
14,232
Location
Woodinville, WA
You're probably seeing 14+ when full, correct? If so, that's normal. You can only measure what you see, and if, during calibration, when the float tops out at say 14, that's the most we'll ever display. So it'll say 14+ until the float comes off the peg.

If we instead treated on the peg as "full" and showed you 18, the consequence would be that when you have say 15 on each side, and you choose your stopping point based on thinking you have 18 on each side, thinking you have another 6 in the tank for reserves, well, you've just planned to arrive on empty. Now 99% of the time you'd probably catch that when your fuel drops from 18 to 14 abruptly an hour or two into your flight, but since fuel starvation is one of the most common ways to end up on the ground before you intended, we made this feature intentionally conservative.
 
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