Frequently Asked


Can I put CiES fuel sender in my type certificated aircraft?

Yes, the installation of CiES FAA TSO fuel quantity systems into most type certificated GA aircraft is approved under a FAA AML STC and an EASA STC.  Based on the success of our proven TSOA process and our commercial success in OEM programs, the FAA authorized STC installation of the CiES digital fuel senders as a replacement for existing resistance or capacitance based fuel quantity in GA aircraft. These senders interface with modern cockpit instrumentation. We are working on adding other aircraft and instrumentation to the STC. 

What is the pricing and availability of the CiES digital fuel sender configured for these applications?

Pricing is per application but the senders average $515+ in each location. These new manufacture digital senders are competitively priced. They are typically available in less than a 2 week lead time. 

What cockpit interfaces do the CiES digital fuel sender interface to?

CiES has a variety of outputs and configurations as we can output a DIGITAL SIGNAL to:

  • Garmin G950, G1000, G500 & G600 EIS TXi
  • Aerospace Logic - FL20XD series
  • JPI 900 or 930 / 960
  • EI CGR-30 & MVP-50


  • Aerospace Logic - Voltage
  • Auracle
  • Garmin

Contact CiES for interface with a standard analog gauge.

What is the pricing of the STC?

The cost for the STC is included in the sender kit price. 

Who is CiES? (pronounced sìse)

CiES Inc. is the leading producer of fuel quantity systems for OEM GA aircraft and rotorcraft, with over 17,000 systems in service all over the world. The FAA worked with CiES to obtain this STC, because of our proven success in the OEM Certified market. CiES’s product line capability spans from small aircraft and UAV systems to Jet and turboprop aircraft. The CC2840 Series digital sender is the second iteration of CiES patented digital fuel quantity technology, and is flown in thousands of aircraft installed and flown since 2012.

What aircraft are approved under this STC?

The current STC provides the most up-to-date information. You may view the STC here.

More aircraft to follow. Your aircraft must have been equipped with a removable resistive or capacitive sender at time of manufacture to be applicable.

How does the CiES sender work?

The system is easy to understand. We place an aligned magnetic field on the pivot so that this field can be measured by an electronic compass which now points to the float. We place this highly accurate compass inside an  aluminum housing and outside the fuel tank measuring the direction of the magnetic field through the aluminum. This solid-state compass electronically points to the float in the same manner that a cell phone compass points to north. It is astoundingly accurate and fuel motion has no impact on operation. 

Are these similar to the Electronics International Magnetic Senders?

While the basic concept of detecting magnetic field is similar in application, the method and components that CiES uses is completely different. The CiES system utilizes Magneto Resistance which is the most stable, accurate and robust technology.

Electronics International uses a Hall Effect sensor, while CiES holds the patent to utilize a more sophisticated, accurate and drift free Anisotropic Magneto Resistive (AMR) sensor.

The automotive industry relies on AMR technology for critical systems like steer-by-wire, throttle-by-wire and brake-by-wire. Due to their incredible accuracy and stability they are used on the camshaft and crankshaft of cars to allow "Stop Start" functionality. 

CiES fuel senders, and only CiES fuel senders utilize an "on-board" brain to process the fuel quantity information and provide a stable output.

The combination of stable, accurate and reliable sensing and the "on-board" processing allows CiES to meet the most critical transport level fuel accuracy requirements  

What does installation entail?

The STC requires that the CC2840 Series digital fuel senders to replace the existing fuel level senders which is a bolt in replacement. The CC2840 Series digital fuel level require aircraft power to operate. A protected power wire needs to be added from the aircraft electrical bus.

Will the CC2840 Series digital fuel sender fit in my tank?

In most GA aircraft, the sender is mounted to the tank structure in a standard 5 bolt pattern. We utilize this same pattern in our billet machined sender housings. In most fuel sender applications, this is a bolt in replacement.

How much does it cost to install?

Initially, this will depend on the installer’s rates and experience. The CC2840 series fuel sender was originally designed to be installed by aircraft manufacturers. Mechanics will be impressed by how easy it goes in. It physically bolts into the same location and only requires an additional power wire.

Installation times for a Cirrus SR22 run 25 hrs, Beech Bonanza's typically run up to 16 hrs and Cessna aircraft are usually accomplished in a day.  

Can I install it myself?

STC installations ultimately require approval from an A&P with Inspection Authorization (IA), and will require an FAA form 337. Aircraft owners who work on their aircraft under the supervision and approval of an appropriately rated mechanic could apply this STC to their aircraft in that manner.

When will the CC2840 Series digital fuel sender and associated STC be available?

Now. We are currently in production with TSO Approved CC2840 Series digital fuel sender. The STC is available from CiES.

Does the CC2840 Series digital sender that can be installed in a type certificated aircraft have the exact features as the CC2840 Series available for the OEM market?

Yes, they are the same product and have the similar capabilities. We repurposed a jet fuel temperature output to allow a low fuel annunciation in the STC sender.  

How does the installation affect the Weight & Balance of my aircraft?

Typically, installing an CC2840 Series senders changes the aircraft weight less than the senders they are replacing.

Does the CC2840 digital fuel sender have TSO Approval? Does CiES have PMA?

Yes, the TSO insures a quality and repeatable fuel level output under all aircraft conditions and the STC demonstrates that these senders are suitable for use in specific type certificated aircraft. This is the only TSO'd fuel sender available for retrofit in GA aircraft. TSO approval insures that the product manufacturing has been accomplished in FAA approved quality system, as such, TSO products do not require PMA. 

What is the pedigree of the CiES CC2840 Series Fuel Sender?

CiES used Cirrus Aircraft, CiES launch partner, to successfully demonstrate that CiES aviation-proven manufacturing and development process yielded a superior product that is suitable for use in all type certificated aircraft. CiES is qualified to RTCA DO-254 and the digital fuel senders exposed to the aircraft environmental conditions for wing mounting by RTCA DO-160.  

How reliable is the CiES fuel sender?

CiES fuel senders have amassed over 800,000 hrs of operation on Cirrus Aircraft with only thirteen removals out of 23,000 senders for cause. This represents a Mean Time to Failure of over 60,000 hrs. This reliability exceeds every other system on the Cirrus aircraft. Cirrus is so impressed that they specified CiES technology on the Cirrus Jet.  

To back that amazing reliability, we warranty the senders for non-transferable life.   

Fuel gauges don't work in GA aircraft, why would installing your product be different?

Original resistive aircraft fuel senders were designed to measure approx. 20 gallons and provide a resolution of 0.3 of a gallon between readings. These resistive senders were intended for automotive and farm machinery applications and are typically made of steel.  The aircraft application places additional stresses on these commercial products, from moisture born corrosion to large movements in fuel in and out of plane of the sender. CiES designed an aviation-grade fuel sender from the outset.  We addressed the moisture borne corrosion issues and also addressed fuel motion in all axis and we designed a system to give excellent resolution.  Our resolution capability is less than (1/10 of a gallon) for fuel tanks that can hold hundreds of gallons of fuel. 

I have a fuel totalizer, why would I need a working fuel gauge?

A functional fuel gauge is required by regulation and is supposed to work as the manufacturer intended. While some people in aviation cast a broad net on what working means, according to the FAA, it means the ability to accurately show usable fuel in each tank. Gauges that waver or show merely a trend in operation are not functional.  Fuel gauges are required, as it takes the fundamental issue of pilot first impression of starting fuel level out of the equation as well as any other fuel anomalies that could happen in flight.  

I heard fuel gauges only have to be accurate at zero.

While even some in the FAA Flight Standards Offices quote this as verbatim truth, it is absolutely not true. CiES works with all of the FAA ACO offices and the FAA Small Aircraft directorate. Usable fuel is an accurate value for every certificated aircraft flying. So yes, zero usable fuel is an accurate number, but so is full usable fuel (that value is on the fuel filler placard and in your POH). Using simple math 1/2 usable fuel is also an accurate number. The zero-fuel accurate myth is just that, a myth.  

How accurate will my fuel indication be?

If you pair the CiES digital senders with a digital instrumentation, we typically see usable fuel remaining numbers within a gallon of a properly calibrated fuel totalizer in level flight and still air. The CiES remaining fuel value will be more accurate the closer the fuel gauge gets to zero. Analog instrumentation and interface will give slightly less accuracy.

Note: There are issues that are part of the aircraft fuel tank design such as sender overlap on multi sender fuel tanks or excessive restriction of fuel flow in a multi element tanks that may cause fuel indication issues. 

Will these sensors work with my existing fuel gauges?

While CiES designed the sender to be able to output to a resistance input analog fuel gauge, there are several issues that make this interface less than ideal. 

First - an analog gauge has its own characteristic and that has to be matched to the tank characteristic. This would be, at present, a remove, reprogram and replace proposition until the gauge and tank content correlate.  


Second - Analog gauging for fuel applied to aircraft utilized gauge interfaces that were not designed to be accurate. We see gauge hysteresis and variations that make accurate fuel reporting nearly impossible. CiES is committed to accurate fuel gauging in aircraft, and these interfaces do not allow that to easily occur.   

Note: if the original aircraft gauge is the only interface that will work for your aircraft, CiES is working on two potential solutions. One will require rebuilt or qualified aircraft gauging, the other replaces the existing pointer driver with a stepper motor.

What is the benefit to having accurate fuel level?

While there are a lot of theories of why pilots run out of fuel, much of what is commonly reported does not have actual research to support the statements.  

What we know, is that due to our involvement in this business and having Cirrus outfitting the system on new SR20 and SR22 aircraft since 2012 we now have a growing number of aircraft where fuel indication is proven to be reliable and accurate. The rate of fuel accidents or incidents primarily attributed to starving the engine of fuel is zero.*

While older Cirrus aircraft, all of which have totalizers, suffer and continue to suffer fuel accidents, this fleet of new aircraft has not suffered a single fuel incident.*

* We have one incident where a severe heroin addiction was implicated, and an accident where the ferry tank fuel valve failed.


Next Generation Can Trust Their Fuel Gauges.

We’re committed to providing an accurate, safe and reliable fuel level reading, as well as providing you with the highest level of service. Once you have installed magnetic field fuel sensing, your fuel level sensing problems will be solved. When you see the difference, you’ll always choose us for your fuel and liquid level sending needs.