New Video - CiES Operation

Why do Aircraft Fuel Gauges Suck

In the 1950’s when a majority of GA aircraft were designed,  the aircraft manufacturers in the USA turned to automotive fuel senders and equivalent gauges made by the same manufacturer - AC DELCO or in some cases Stewart Warner.

Rebuilt Piper Comanche Sender 

These gauges and senders were produced by the millions for the primary automotive application Buicks and Cadillacs in the mid 1950's.  I get a sense looking at these senders and gauges now 50 or 60 yrs later that there was a sense of pride,  they did last far longer than they should have.  But even 50 yr old automobiles have issues.

The trouble with these automotive senders is that they are: 

• Made of Steel. 
• Only in production for a few years. (more of this later) 

Fuel tanks for both applications automobile and aircraft were very similar in size 

• The sender and gauge face size that were matched. The indication size allowing for  the automotive requirement to provide a warning of impending fuel starvation.

• Interesting note:  in that automotive systems are biased to show a faster fall in fuel level from 1/2 tank to zero - the Big Three were trying to keep car owners from running out of fuel.  That clever manipulation is still being used in automobiles today.

Now because aircraft are aluminum we have introduced dissimilar metal corrosion.  Steel sender body and aluminum aircraft tank or structure.

Water vapor introduced on descent is one of the reasons we sump the tank before flight.  But water vapor also condenses on the steel sender body.  Water increases the rate of galvanic corrosion.

What else is necessary, oh yeah, latent time, when the aircraft tanks sits empty waiting for the next flight. 

What is worse - is that we stuck the resistance measurement method inside this little corrosion lab - it degrades right along side the metal in the sender body and just as quickly.

Fuel senders last longer if they get the regular washing with fuel.


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So now just for fun,  we have introduced corrosion by products into our fuel stream,  rust and rust particles threatening fuel passage.

Now with totalizers, we added a little turbine to measure fuel

We should replace the senders every so often,  yes that would be a good plan - the only issue is that that particular automotive sender is no longer made.

So to accomplish this lofty ideal you would have to wholesale replace the senders and gauges - Cessna Parts Distribution only reports 4 to 5 sales per year for a program like this.  I was told it was a single persons job for 5 years to put together this program.  Somebody thought it was worthwhile.

First for the Stewart Warner System and then for the Rochester Gauges unit (an Aluminum Body finally)

It should have been required - it should have been made into a Mandatory Service Bulletin - Actually it has and actually it is. 

Nobody pays attention to it, very few are aware it exists.  

Piper, Mooney and Beech have similar 

Fuel tanks got larger over time  and only Beech and Cessna in the Twin aircraft   increased the fuel gauge size for better recording accuracy 

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Well where that leaves us is with marginally operational gauges that for a very good functional reason nobody would trust, as they weren’t designed for the job. 

But instead of fixing the issue, and Cessna did try and so did a few others - pilots and aircraft manufacturers  just gave up.  They gave up on new technology, they gave up on new designs. 

Who would want to fix it - if nobody cared or even though they though they didn’t need a functional fuel gauge.



So when a pilot says he trusts his watch or his unapproved  Minimum Equipment List stick or some other fancy but non-required workaround and that they state emphatically that they wouldn’t trust a fuel gauge 

• We are fairly certain they are flying with un-airworthy fuel gauges and senders that haven’t been serviced or calibrated 
• We are dead certain of the lack functional fuel indication capability in an aircraft,  when the pilot emphatically states that fuel gauges don’t have to be accurate or only accurate at zero 

The ridiculous part is that the magazine pundits agree with them, all for a system, that was by it’s very design was going to fail 

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This is the saving grace - CiES now has over 85% of the OEM general aviation fuel sender market - All of Textron Piston and All of Cirrus Piston and Jet  - and a large smattering of others 

The aircraft manufacturers, do not agree with the magazine pundits, and that should be a sobering moment.  Internally in the industry when we have discussions on this topic and the concerns are completely foreign to what is perceived by the pilot community believes.

Aircraft Manufacturers Requirements

• Aluminum Body - that has an additional element of corrosion protection.
• One less thing to introduce rust into the tank environment
• Designed for the harsh aviation environment - DO-160 Testing
• Repeatable and reliable accuracy over the aircraft life.
• Measurement method removed from the fuel volume 
• Intrinsically Safe 
• The ability to effectively stick the tank anytime in level flight
• Digital system to offer the a better owner satisfaction and reduced warranty claims 
• They wanted fuel quantity solution for life of the aircraft 

Aircraft manufacturers know that fuel totalizers, did not and do not fix fuel starvation as Cirrus aircraft in particular had several notable events 

The funny thing is that this new GA fuel quantity system can be retrofitted to older aircraft -

It has the potential to make all aviation fuel level gauges functional - more importantly TRUSTED.

OSHKOSH RECAP - CiES Aircraft Fuel Senders

We are coming to an end of our first trip to OSHKOSH AIRVENTURE.  To say it was a success would be an understatement.  

The three most common comments we heard were 

• "It is about time that somebody fixed aircraft fuel level" 

• "Is is STC'd for my aircraft

• Discussions of personal near miss fuel starvation events. 

Lucky for us several of the alphabet groups decided to stop by and pay us a visit.  They listened as we did, as one by one, potential customers stated all of the above.   

It was a sobering for them.  The magnitude of the issue we have created in aviation, by ignoring fuel quantity indication,  became very evident.

For the first time, somebody other than CiES confirmed  what we hear every working day. 

Fuel indication as we know is less than aviation grade in legacy aircraft.

We are dead set on changing that.  

AOPA Pilot - May 2013

AOPA Pilot

The press is taking notice of the new digital fuel level senders in the new Cirrus aircraft.

In this case AOPA Pilot and Tom Horne

Here the new fuel level  senders are being discussed with the integration to the standard Cirrus Garmin Perspective Panel.

We agree that accurate fuel level makes it much easier to manage fuel and payload 

The dialogue we started a year and a half ago 

That accurate fuel level in aviation will allow for a higher level of integration, and relieve pilot workload

These innovations are reaching the light of day and in now in production

Tank level balancing and enriched warnings are now reality

We've taken on a new look

Beech Customer Responses

Beech Customer Responses

I have the CiES frequency senders, with matching Aerospace Logic gauges.

Working with Aerospace Logic requires patience, but in the end, the result is really spectacular.

Yesterday, at 8500 AGL, I ran both R&L Auxiliary tanks down to 0.0 gals, at 47:35 on the clock, precisely as expected... A few seconds later... Fuel pressure begins to fall, immediately switched back to left main.  

Accuracy... It's a totally new experience. I have two fuel totalizers. One Shadin and one in my G4.  Maybe having accurate fuel gauges is overkill... But it's an overkill that I like. 

The only caveat is that my shop wasn't particularly efficient with the remove / reinstall / remove / final install / calibrate process.   I have ALOT of money tied up in this.   But I don't regret it, and I would do it again. 







For anyone who is considering CiES fuel senders these things are awesome. They are well worth the work to install. I ran all new shielded conductor up to the back of my JPI 930. Finally I have a reliable and consistent fuel measurement in my airplane. 

Wow, who would have thought accurate fuel level was possible.

If your airplane is down for an upgrade I would send your old fuel senders to CiES.   This will insure that the senders are appropriately set up the first time.   Beech in all their wisdom made numerous different senders inverting the bolt patterns on some etc. 

CiES senders can work by resistance, voltage or frequency. I would chose at a minimum voltage if you can, Frequency is even better.
Scott @ CiES knows his stuff.


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The cost to retrofit CiES senders to a pre-74 B55 is around $3200 (plus installation). That may seem "outrageous" but it's only about 50% more than what it costs to have the eight (2 per tank * 4 tanks) senders "overhauled" and my experience with overhauled senders is not very good. At best the overhauled senders will perform as good as when new for a few years which is to say they're accurate to within about +/- 5 gallons.

Properly calibrated the CiES senders appear to be within one gallon.  In a Bonanza with two 40 gallon tanks or a post 1973 Baron there are only four senders so that cost is cut in half.

 IIRC the last time I checked, new (1940s technology based) senders from Beech were around $1,600 each or over four times what CiES charges.

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+1 on the CiES/ Scott Philiben Phan club. There's no better customer service than that provided by Scott. anywhere.

I'm still VERY happy with my CiES senders. You know, when something "just works", you take it for granted.   I don't really give my CiES senders much thought. 

They're underappreciated little heros quietly doing their job. Perfectly. All the time.

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AIRCRAFT FUEL GAUGES THAT YOU CAN TRUST 

"With over 12,000 units now flying, CiES has taken over the OEM fuel level sending field.   Our combination of outstanding quality,  reliability, and accuracy has made CiES the standard and the runaway industry leader for fuel level indication on all aviation platforms, GA, Utility, Rotorcraft for both reciprocating and turbine engine applications " 

A New Day has Dawned in Aviation

General Aviation News Photo

“Getting this STC done has created the roadmap for us to continue on,” said Pelton, noting that other STCs may involve fuel systems, autopilots and more."  General Aviation News 

We have made great strides in replacing legacy fuel quantity indication in GA aircraft and Jack Pelton's comment above, indicates the importance of improved fuel quantity indication in the roadmap to improving the equipment on legacy GA Aircraft.    

Today's EAA STC news announcement opens up the literal Pandora's box of opportunity.

Actually our FAA TSO approval allows us to move even faster into getting universal approval for installing better fuel quantity systems in GA aircraft.  

The TSO approval insures that we have met both the new ASTM standard for Verification of Avionic Systems but also the RTCA DO-254 Design Assurance Guidance for Airborne Hardware as well as the DO-160 standard for surviving the external environmental conditions found on the wing of the aircraft 

This is a major step forward and was not anticipated after the Part 23 Rewrite NPRM.  

The new ASTM Standard makes it much easier to show compliance with organization, definition &  verification of our software.   

Utilizing a smart sensor was key to CiES obtaining the outstanding aviation fuel level sensing results.  

This quality indication is one that thousands of pilots rely on,  flying brand new Cirrus, Vulcanair, & Quest aircraft.  

Contact CiES as we are adding fuel quantity sensor configurations for thousands of single engine and twin aircraft. 

• Cessna
• Beechcraft 
• Piper
• Cirrus
• Brittan-Norman
• Fairchild 
• Technam

Aviation Fuel Level Indication - Customer Responses

Customer Responses

The cost to retrofit CiES senders to a pre-74 B55 is around $3200 (plus installation). That may seem "outrageous" but it's only about 50% more than what it costs to have the eight (2 per tank * 4 tanks) senders "overhauled" and my experience with overhauled senders is not very good. At best the OH senders will perform as good as when new for a few years which is to say they're accurate to within about +/- 5 gallons.
Properly calibrated the CiES senders appear to be within one gallon.  In a Bonanza with two 40 gallon tanks or a post 1973 Baron there are only four senders so that cost is cut in half. IIRC the last time I checked, new (1940s technology based) senders from Beech were around $1,600 each or over four times what CiES charges.

I'm having a hard time seeing anything "outrageous" with CIES pricing.

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And one additional point about CIES senders. I have absolutely no doubt if any question or issue came up, Scott would be on the phone within the hour. (More likely in minutes.) Every interaction I have had with him and interactions I have seen others have with him have been very positive. 

Phone or email he's always been very helpful.

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+1 on the CiES/ Scott Philiben Phan club. There's no better customer service than that provided by Scott. anywhere.

I'm still VERY happy with my CiES senders. You know, when something "just works", you take it for granted. I don't really give my CiES senders much thought. They're underappreciated little heros quietly doing their job. Perfectly. All the time.

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AIRCRAFT FUEL GAUGES THAT YOU CAN TRUST 

"With over 10,000 units now flying, CiES has taken over the OEM fuel level sending field.   Our combination of outstanding quality,  reliability, and accuracy has made CiES the standard and the industry leader for fuel level indication on all aviation platforms, GA, Utility, Rotorcraft for both reciprocating and turbine engine applications " 

Piper PA-31 Navajo Fuel Quantity Senders

Piper Navajo Fuel Quantity Senders  

We just completed a set of Piper Navajo senders for Mike Jones Aircraft.   

We replaced the old resistance sender design with the CiES Magnetic Field design .  Like a lot of well regarded aircraft, the Piper Navajo has not been supported by the factory for some time and the existing replacement senders either don't work or they have outlived their ability to be effectively re-worked along.

The CiES fuel level sender is built for the Navajo application, with a custom arms dedicated to each location on both the main and the auxiliary tanks.  Our non-contact fuel quantity measurement method insures that leakage can not happen through the sender body.  A modern digital sender component to compliment a modern digital cockpit interface, like a JPI or Aerospace Logic.

All of our sensor electronics are fully enclosed in the aluminum housing.  Unlike traditional failure prone senders - our senders have amassed an impressive record of 350,000 hrs of flight time without error or in service replacement.   

We will change your opinion of what float fuel senders are capable of - both from a precision and reliability standpoint.

Finally a fuel level sender specifically designed for the aviation market.

Vulcanair P68 Service Bulletin - Digital Fuel Level Digital Fuel Level

Vulcanair P68 Service Bulletin - 

The two new fuel senders are of magnetic field typology and their output is a digital square wave signal whose frequency changes according to the fuel level in the tank.

This new fuel sender uses one wire to interface the level indicator by which it transfers its output frequency to the indicator and a second wire to get a voltage supply, typically  the 28Vdc of the aircraft.


Vulcanair is the second OEM Aircraft manufacturer to utilize the CiES Digital Fuel quantity sender for installation on all of it's aircraft.   

Vulcanair is the first manufacturer to offer a retrofit Service Bulletin Kit to install the system on legacy Vulcanair and Partenavia Aircraft.  

 
AIRCRAFT FUEL GAUGES THAT TELL THE TRUTH 

"With over 10,000 units now flying, CiES has taken over the OEM fuel level sending field.   Our combination of outstanding quality,  reliability, and accuracy has made CiES the standard and the industry leader for fuel level indication on all aviation platforms, GA, Utility, Rotorcraft for both reciprocating and turbine engine applications " 

Cessna Pennycap Press Release - Flying Magazine May 1968

Cessna Pennycap

Copyright Flying Magazine May 1968

Curiosity got the best of us the other day, and somebody wondered if there was a similar example to a disruptive fuel level technology in General Aviation aircraft.   I indicated that there was a different system and it enjoyed a brief and limited success.  This system came out in the late 1960's and was featured on Cessna aircraft.

I went for a magazine search for press releases, curious to see what virtues would be given to a better fuel quantity system.

This system was produced by Consolidated Airborne Systems - which still operates out of a garage location in New York state.

The headline for the article was entitled 

GAS GAUGES THAT TELL THE TRUTH 

"General aviation airplanes - those engineering marvels, this distillations of technical wisdom and aeronautical magic incarnate - use fuel measuring devices of the same arrangement that plumbed fuel quantity in automobiles since the Model A  float tipped rods that electrically drive instrument panel needles to positions approximating the volume of fuel left.  Many such devices are off by as much as 25 percent" Copyright Flying Magazine May 1968

Many mechanics swore at these systems, many are swearing at them still.  The never lived up to the billing as corrosion on these low cost systems quickly robbed them of any accuracy advantage.  If you remember - Penny was to indicate "low cost" and cap was to indicate "Capacitive"  i.e. Pennycap system by its marketing title was a low cost capacitive fuel system.

"For not much more than the cost of an annual, then you'll be able to have a fuel gauging system of honest go/no-go quality.  Can you hold in the soup for 45 minutes at your alternate, or should you declare an emergency and tell them to get you down?  Can you afford to try and get out of that mountain strip with half full tanks and your present baggage load, or are your tanks more like three-quarters full?  It can make a difference." Copyright Flying Magazine May 1968

What is old is now new again - as 48 years later for the price of an annual you can have a CiES fuel gauging system of honest go/no-go quality. 

Customer Responses - CiES Non-Contact Fuel Level

Cessna 177

Hi Scott,Our senders have been working perfectly with the Aerospace Logic gauge since installation last August. Thank you for your outstanding support in helping us work through an unrelated ground wire issue in the plane.Gregg Ridder

Mine have worked flawlessly since installation, and the accuracy appears to be extremely good. Hopefully someday I’ll be able to quantify that accuracy. I sure wish other aviation vendors cared about their customers like you do. Jerry Olson, 76 C177RG

Hey Scott,
I presume you got the original frequency senders back by now? The new ‘voltage’ type senders are working fine with my old(er) JPI 930. I did calibrate them (again) when installing them, however, they fail to indicate the full 30.5 gal on each side on the 930 when ‘full’ (JPI’s display units do not show partial gallonage). Most times the 930 reads 29 each side when “full” (full is over 30.5 gallons each side, sometimes QUITE a bit more). However, when I fill up, I can tell you the amount put in + the 930 readout of what’s left is almost spot on, close enough to more closely calibrate my K factor in the 930 installation (it’s still off quite a bit). I also double check with my fuel dipstick. And I did level the plane while calibrating, even though the Cardinal cruises nose down, so calibration methods give differing results depending on nose strut extension, attitude, cross level, etc.
Any my 930 still shows the digital amount remaining.
So I’m happy. Much better than the OEM stuff and those original gauges.  And it will get better with more flights.
Too bad you can’t get JPI to include your senders when new fuel reading units are ordered.
Marc, 76 C177RG 

Everyone, Mine are installed (Bob Russell) and interface properly with the JPI 930.  Fuel readings seem to be extremely accurate.  I can read the remaining fuel from the JPI, and then stick the tanks for a comparison.  So far, readings are within .5 gal of what I measure.  Scott, excellent product.  Thanks for supporting CFO and members.Alan, C177RG