CIES Inc

Can a fuel sender be too accurate?

When fuel moves in the tank, an accurate sender may show it. That doesn’t mean the measurement is wrong,it may mean the system is detecting changes older technology simply couldn’t see.

Our latest blog looks at the difference between accuracy, stability, resolution, and how that information is ultimately displayed to the pilot.

Read more: https://ciescorp.net/your-senders-are-too-accurate

Your Senders Are Too Accurate - CiES Inc. One of the more unusual comments we occasionally hear about CiES fuel senders is that they can seem “too accurate.” At first, that sounds like a contradiction.

Planning an avionics upgrade? Don’t leave your fuel quantity system in the past!

Pairing modern glass cockpit displays with outdated, resistive fuel senders limits your panel's true potential. Upgrade to digital CiES fuel senders to get certified, full-range accuracy and seamless cockpit integration.

Read our latest blog post to see why precision fuel sensing should be a top priority during your next panel overhaul: https://ciescorp.net/upgrading-the-panel-dont-leave-your-fuel-quantity-system-behind/

Upgrading the Panel? Don't Leave Your Fuel Quantity System Behind. - CiES Inc. Modern avionics upgrades can transform an aircraft with better situational awareness, improved engine monitoring, and more described here.

What does it mean when fuel quantity actually goes up in flight?

In early Beechcraft Bonanzas, the fuel system can return excess fuel to the left main tank—even while drawing from another tank. With accurate, repeatable fuel measurement, you can actually watch that transfer happen.

It’s a great example of how accurate fuel indication reveals more than how much fuel you have. It shows what your fuel system is actually doing.

Read the full story: https://ciescorp.net/when-fuel-quantity-goes-up-in-flight/

When Fuel Quantity Goes Up in Flight - CiES Inc. Fuel quantity normally has a very predictable relationship with time. In some early Beechcraft Bonanzas, however, that assumption is not always correct.

"Only a stupid pilot runs out of fuel."

Every pilot agrees with that sentence. That's exactly the problem.

Say it to the guy who tops off every tank, never flies a leg over two hours, and gets twitchy the moment the needle passes half — and he'll nod along. Obviously that's not about him.

Here's what that pilot knows and believes: the FAA's own Pilot's Handbook states that fuel gauges are only required to be accurate at empty. Everywhere else in the flight, they're allowed to lie.

That's not a fringe reading of an obscure rule. It's printed, verbatim, in the primary training manual every student pilot learns from.

Except it's wrong. The actual regulation — 14 CFR §23.1337 — requires the gauge to indicate usable fuel during flight, not just at one point in it. The empty-point calibration is additive, not a ceiling.

Compare that to ignition. A bad magneto grounds the airplane, full stop — no argument, no workaround culture. It shows up as an RPM drop on runup, and every pilot checks for it before every flight. A fuel gauge that's wandered for months just... keeps flying.

Same engine. Same two equal ingredients for combustion. Wildly different tolerance for a known fault.

I spent years tracing this — through the regulation, through FAA guidance, through manufacturer service bulletins, through a comparison with Australia's civil aviation authority, which requires full-range gauge testing every 48 months and tells pilots plainly never to trust a single fuel source.

The full piece is linked below. It's not a call to trust your gauge blindly — good airmanship never goes out of style. It's a case that the industry has spent 50 years training pilots to distrust an instrument that was never supposed to be untrustworthy in the first place.

Scott Philiben, Founder CiES Inc.

https://ciescorp.net/the-myth-that-runs-through-the-whole-system/

Confidence changes the way you fly.

"I've flown 30 hours with the new units and they're awesome. I am much more confident stretching my flights to five hours knowing the fuel on board accurately, and partial fueling is much more precise."

Reliable fuel level information helps pilots make informed decisions every flight.