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Friday, February 5, 2016

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 


"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. 

Monday, January 25, 2016

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

Tuesday, November 3, 2015

Early Bonanza Fuel Quantity Senders

Early Beech Bonanza Fuel Senders

What are the steps we need to take to build fuel senders for your aircraft: 

  • Obtain a a set of old fuel level sensors from the aircraft we are considering (see the lower portion of the picture on the right).  If the IPC part numbers for the supplied senders match the aircraft they are on, we are good to go.
  • Ideally this aircraft should have a strong user base with an owner that demonstrates a willingness to embrace new technology with their pocketbook.
  • Discuss the compatibility with commonly installed MFD components or instruments.  We prefer instruments that accept digital input like Aerospace Logic, Garmin & JPI.
  • CiES  Fuel Level Senders now has the capability of driving even old analog gauges in the aircraft (Universal Fuel Level)..
  • Our market is the pilot / customer that is more concerned with fuel level issues and wants the required fuel level instrument in the panel to have the  capability of multiple point calibration.
  • Evaluate the existing sensor design -  For example the bends in these sensor arms are either to assist in installation and removal of the fuel sensor or to clear aircraft structure in the fuel tank.
  • As our sensor design allows for an easily detachable arm - these bends might not be necessary and simplify the design greatly.
  • We then proceed to manufacture a conforming sensor with our best guess for geometry.
  • Check the sensor in the aircraft fuel tank.  As you can see in the illustration - in this case the simple arm design works better in the tank and sweeps a better fuel volume being closes to the Spar and maximum chord point.
  • At this point we qualify the design with drawings and procedures for the completed unit so that we can send these files to the FAA to have this configuration added to our TSO.
  • Once we have approved drawings we can can produce the required sender with a TSO Tag attached.
  • The fuel tank is then drained, the aircraft leveled and braced only then is the zero fuel amount added.  There should be movement of the sender to be able to record an accurate zero fuel level, this is an absolute requirement.
  • Fuel is then added to the tank incrementally and accurately to obtain data points for calibration.  We direct the installer to take special caution to insure tabs fuel value is accurately recorded by the fuel display.
  • Equally the installer needs to insure full fuel level per the POH is also accurately displayed.   
Note:  All aircraft fuel tanks are built with expansion volume - Full fuel per the POH may or may not be to the neck on the filler plate.  This is very important as the aircraft will probably be fueled in the future on a ramp - 

Wednesday, October 21, 2015

100% of Aircraft that Suffer Fuel Related Accidents have Non-Functional Fuel Gauges

That's a pretty bold statement.  

While the FAA and NTSB do not as a rule, evaluate or test the fuel quantity system in the fuel starved aircraft the same is not true for other national safety boards or aircraft regulatory agencies. 

These foriegn agencies and boards have determined that fuel indication plays a large part in fuel related accidents.

In fact these agencies and boards have petitioned our FAA to issue guidance or an Airworthiness Directive on the fuel quantity systems that they found to be less than functional.  

It is unfortunate - but in the aviation world we need to describe what a functional fuel gauge is.


A Functional Aircraft Fuel Gauge has the following two Characteristics

  • In level flight the indicated amount of fuel shown on the gauge should be within 3% of actual fuel volume in the tank.  
  • When the fuel is at a low level demonstrated to the FAA to be the minimum fuel that can be drawn from the aircraft in all normal maneuvering flight conditions this demonstrated fuel quantity will be the "Zero" or "Empty" fuel level value.

For reasons that we have discussed in this blog  - there are reasons and a history for why we in the aviation community treat the required instrumentation for fuel quantity different than all other required instrumentation on the on the aircraft.  

When you take a step back and look at it the context of what aircraft fuel level indication should be vs. what it is or what it has become.

There is room for improvement,  but most pilots believe that fuel indication will never change and they definitely won't rely on it.

Let's make aircraft fuel level indication functional to the two characteristics indicated above and use them to provide adequate warning of unplanned fuel usage or fuel loss.  

With this vital information available to pilots for actual fuel quantity in the tanks, pilots will make better decisions.

Monday, October 5, 2015

Beech Baron Digital Fuel Sender Retrofit Part 6

Beech Baron 58 Fuel Level Senders

CIES Baron 58 Fuel Quantity Senders

We have some results back on the Baron 58 Senders.    There was a slight glitch as the middle left sender somehow got caught on the initial calibration.  But that was rectified easily   

The result was a fairly simple curve with no major discontinuities - Nice Job.

Even better we got a good result in the air.  

We got the middle float unstuck on the left side, it was helpful that with a frequency output graph that you could pinpoint the problem remotely like that.
After it was free, we mirrored the calibration numbers on the right side with the offset we had from the first reading and They  seem very accurate,  within a gallon of the totalizer on the JPI 960.
Tank calibration curve
We put lots of work on this aircraft... we did air conditioner, new engines, props, & avionics.    The owner has flown in it,  but we are still tweaking and breaking in the new engines for him.   

So a gallon or so off of the totalizer on a 150 gallon aircraft -  Not bad at all. 

Legacy Beechcraft Senders

All dimensions for these new senders  were captured from a legacy set of Beech Baron 58 Fuel Level senders.  As the CiES design constraints are different from the legacy senders - there are a few little tricks to getting the right geometry in the tank 

For this short flight fuel level is in green and fuel flow in blue.  You can see the effects of pitch change on fuel level on takeoff and landing. But you can also see the steady drop in fuel level over time.

This was our first multiple sender summing aircraft and we are very happy with the result. 

We were looking forward to this system in the aircraft as it represents a chance for us to utilize the capability of summing multiple senders to achieve a single digital fuel tank output.  

Every day we see that we can meet or exceed  the 0.75% most stringent TSO quality standard.  In the case of the Baron - that would be 0.66% accuracy for fuel quantity. 

Friday, October 2, 2015

Beech Baron Digital Fuel Level Sender Retrofit - Part 5

Beech Baron 55 Fuel Level Senders

We have now produced the Baron 55 Senders.  These senders are fully TSO'd and presented our largest challenge to date as each sender had a unique peculiarity.

We will wait for confimation in the aircraft that all is well as we did for the Beech 58 senders we completed two weeks ago 

We are looking forward to this system in the aircraft as it represents a chance for us to utilize our capability of giving a multiple tank system, Mains and aux tanks accurate fuel level.

Stay tuned for further updates and pictures.

Britten-Norman Islander Fuel Quantity Senders

Britten-Norman Islander Fuel Quantity Senders  

We just completed a set of Britten-Norman Islander senders for the manufacturer.   

We placed the old Britten-Norman sender design alongside the CiES design for contrast.  Like a lot of small aircraft manufacturers, Britten-Norman had to modify commercial resistance senders to work in their application until we came along.

If you look closely you will see the careful welds on the legacy sender float arm and if you look inside you will see tank sealant applied to the riveted and electrical connections to prevent fuel leakage through the sender body.

The CiES fuel level sender is built for the application, with a custom arm dedicated to this assembly.  Our non contact fuel quantity measurement insures that leakage will not happen through the sender body.  

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 300,000 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 designed for the aviation market.