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Friday, April 10, 2015

The Three Fundamental Truths About Aircraft Fuel Level


We have a unique perspective to aircraft fuel level,  in that CiES works daily on these systems.  We see the good, the bad and the downright ugly.


What we have observed and are sharing here is what CiES has determined to be the

Three Fundamental Truths about Aircraft Fuel Level Systems. 

Here they are:

If the technology of fuel level measurement can find the surface of the fuel reliably. 
    • Floats that actually float or are allowed to float.
    • A set capacitance based on fuel level in a tube (ignoring temperature & other fuel dielectric effects).
    • Ultrasonics tend to get messed up with foaming fuel. 
If the basic sensor system can output a lot of data related to fuel level. 
    • A capacitance fuel level system can output a theoretically infinite number of data points - but realistically in an actual fuel level device -  potentially 10,000 to 30,000 data points 
    • Our Magnetic Field Technology has 10,000 to 12,000 data points.
    • A legacy potentiometer system that provides maybe 50 or 60 data points (wiper and trace size controlling the data point size) 

If your fuel level display system can capture the complexities of a fuel tank curve  
    • a non linearly marked fuel gauge or an Multi Function Display with a calibration feature

Then if these three criteria are met - you will have an excellent aircraft fuel level system - meet a few of them and your fuel level system will be functional. 

As we know the world isn’t perfect -  

To make a old aircraft fuel level system work well -  You need to make a unique potentiometer, carefully assemble it to reduce internal friction, maintain wiper contact and hope it all holds together and doesn’t corrode.  

Now combine the above with a non linear and an easy to calibrate gauge.  This is fussy work at best.

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Here is  our real world challenge  - 


  • Say for example you have a simple fuel gauge marked with the same distance from Empty to 1/2 tank, & from 1/2 tank to full 
  • We are all very familiar how long it takes to go from Full to 1/2 Tank and that it takes a fraction of the time to go from 1/2 Tank to Empty.
    • The above is a fundamental universal truth. 
  • Therefore because CiES can  - we load a tank table with a characteristic curve onto internal memory on the sender.
    • Log, Sine, 3rd order, 4th order, 5th order, Non Linear - You name it - We can do it - challenge us.
    • Of course we need the tank function and a simple gauge to get it right.
  • Unlike a potentiometer - we don’t have to cram all that onto a circuit card by physically making the small steps with variably positioned traces, or onto a carefully delineated gauge.
  • We have 10,000 reliable data points with our sensor technology - we just do it in software - easy peasy. 

Just don’t tell me that fuel gauges only have to be accurate at empty - we get all apoleptic.


Wednesday, April 8, 2015

Cessna - New Technology Non-Contact Fuel Level Sender

CiES Inc, Cessna Fuel Level Sender 

We are in the process of serial manufacture of a Cessna Fuel Level Sensor.  

Cessna Fuel Level Sender 
This fuel level sensor utilizes our patented magnetic field technology and carries FAA TSO Approval.  

Note:  TSO Approval is FAA component approval and not FAA installation approval.


We set out in 2010 to change the dialogue about fuel level indication in aircraft & we accomplished this by building an aerospace specific fuel sender design.  


Fuel Level Sender Exploded View
This new fuel sender design, while resembling older technology potentiometer fuel level senders, centers around a robust patented non contact sensor technology.  

The only common part between our fuel level sender and old technology is the float.  You can see the CiES attention to detail we are internationally known for.

Our goal was to design a fuel level system that had the potential of replacing many legacy aircraft fuel senders in the field.  Our initial fuel sender production was utilized almost exclusively by OEM aircraft manufacturers and to meet OEM requirements they utilized a robust proprietary digital output.  Unfortunately this output was only suitable for Garmin G1000, JPI 930 & Aerospace Logic displays and instrumentation.   We have produced over 7,500 non contact fuel level senders in this configuration and the results have been exceptional.

Our recently issued TSO allows us to reach and support a broader range of cockpit fuel indication interfaces and as a correlation allow CiES to spread it's wings so to speak.   This new sender design allows the CiES fuel level sender to output a variable voltage or resistive load giving us a nearly universal capability to support legacy aircraft.

As such, we are actively working on CiES fuel level solutions for many popular aircraft. 

Contact us and see if we have a solution for your aircraft.

Saturday, March 21, 2015

FAA TSO'd Fuel & Oil Level Senders

Another Milestone Accomplished 

We received our second TSO C55a designation for our aviation fuel level senders. 

To meet this requirement our senders were rigorously tested in in harsh environmental and electrical conditions.

In these conditions, the CiES senders had to provide a stable and effective fuel level output.

Our output quality level met the most rigorous FAA TSO standard for fuel level sending @ 0.75% of full tank volume.  A fuel level standard that the big iron fuel senders can only hope to achieve. 


Meeting these standards proves that CiES technology provides an accurate fuel level output for any aircraft or rotorcraft type.


The fact that a float based sensor meets this critical FAA requirement - proves our technological and patent advantages, as
only CiES produces FAA TSO Approved Float Sensors. 

Additionally there are no wires or electrical components in the fuel volume.  The requirements of the FAA Advisory Circular AC 25.981-1C - Fuel Tank Flammability are inherently met in our fuel sender design.


What was Added to the New Sensor

  • Universal Level Output
    • Resistance 
    • Voltage
    • Frequency
  • Fuel Temperature Output 
    • Lbs or Kilos Fuel Level Capability
  • Flying Lead Connection
    • Better Connection Flexibility
    • Unlimited Connection Interface.
    • Can Accommodate Limited or Tight Connection Clearance  
  • Simpler Data Transmission Between Senders.
  • 7 fold Increase in Output Sensitivity
  • Improved Flexibility in Meeting Future Fuel Level Challenges
    • Larger Data Processing Headroom
    • Filtering and Smoothing 
    • Internal Fuel Tank Mapping Capability  

Tuesday, March 3, 2015

Heli-Expo 2015 - AS350 Fuel Tank

Heli-Expo 2015

We are happy to show the Robertson Fuel System - Airbus AS350 Tank in the Vector Aerospace booth.

Our fuel level indication system is finding favor in many applications.

The unique nature of our magnetic field technology makes for a robust and accurate fuel level sender.

We have produced rotorcraft fuel senders and fuel senders for Jet A fuel applications, but this combination is a first for our application.

Our capability is exceptional and we are excited every time we are able to prove this in a new application.

We change opinions on how an accurate fuel level can be attained and are replacing legacy fuel quantity systems in the field

Check into our capabilities and we will change your perceptions.
















Wednesday, January 28, 2015

Cessna - Friggin Lasers in Their Fuel Tank

Hidden Costs Behind the High Cost of Aviation 

I had started to re-energize our 2015 marketing effort  and wrote a few blog posts about delivering magnetic field fuel senders to,  new to us,  European Aircraft and Helicopter customers.  We seem to be popular over there,  we may owe many thanks to Flieger editor Thomas Borchert  
To check on our progress on our google search listing placement,  I ran across a G1000 Cessna Fuel Sender for Sale on Ebay  and thought I'd share it.
This is a Meggitt TDR (Time Domain Reflectometry) Fuel Level Sensor for a Cessna Single Engine.
  • Used Ebay Price is $1,800 each
  • New Price from large Cessna Parts Jobber is $3,100
  • Cessna List Price is $3,864.  
The Meggitt Fuel Level Sensors do look well made and come with a nice calibration sheet for your Cessna 172, 182 or 206.
Replacement Cost for 2 of these sensors on a Cessna would be $7K to $8K a Kit -  Installed cost would be well over $10,000 - This for a retrofit fuel level system on a Cessna 172 for heavens sake.  It is painfully obvious why there isn't a retrofit STC available.
Maybe some in aviation are correct,  airplanes are getting to be very expensive  - part prices contributing greatly.  But with a bit of creativity, it doesn't have to be.   
The caveat is,  that our Fuel Level Sensors met all the FAA TSO requirements that the TDR fuel sensor has met - and we do it for far less money.  I was told early on,  Engineering is not building the best without regard to cost, it is providing best performance at a price that is attractive to your consumer and the FAA.   
While I have heard that our FAA TSO fuel level sensors are expensive compared to legacy commercial grade resistance fuel senders, i.e. the kind of sensor they used to put in aircraft of the past.   I agree to a point on the expensive part arguement, but I truly feel CiES hit the target.  We provide improved aviation technology and performance at a competitive price. 
This Meggitt TDR sensor is not a well known change to the venerable Cessna Single Engine Lineup,  you would be hard pressed to know this was in your wing unless you queried the Cessna Illustrated Parts Catalogue.   There is no mention of this system any Cessna Marketing literature.   You'd think that a $8,000 fuel level system would be worthy of editorial or marketing content  - I guess it isn't.

Almost overnight the world of aviation fuel level changed and somehow nobody bothered to notice.

The TDR system works by shining laser light down a glass rod and measuring returns, so next time you come in contact with a G1000 Cessna owner - Let them know they have "friggin" lasers in their fuel tanks. I am going to bet they'll be surprised.

Monday, January 26, 2015

Magnetic Field Fuel Level Senders - Resistance Output


 Another Day And Another New Fuel Level Sender Configuration @ CiES 


While we discussed the Universal Output Sender in a previous blog post, it's much better to talk about an actual fuel level sender we are sending off to it's intended OEM manufacturer.   

This new configuration will output an equivalent resistance to be read by a gauge or the aircraft MFD.   While it appears on the surface to be easy it is actually the result of a 3 year effort to provide an output suitable for the aviation environment.   

Our senders are natively frequency output based, and this output has proven to work very well in our OEM and retrofit applications for Cirrus Aircraft,  but what we needed to do was convert that frequency to either a voltage or resistance output.

So we manipulate this native output to provide a variable voltage or a variable resistance.  

This unit for a new customer contains everything we wanted to provide;


  • Frequency Output Fuel Level
  • Slave Sender Input
  • Resistance Output Fuel Level
  • Fuel Temperature 

It is the culmination of making a Fuel Sensor that is compatible with most platforms out on aircraft & helicopter platforms in the field.


Friday, January 23, 2015

Cessna Cardinal 177 Fuel Sender Design Process

Can we offer a Retrofit CiES Fuel Sender for your aircraft. 


What are the steps we need to take: 


    New Cessna 177 Cardinal Fuel Level Sensors 
  • Obtain a a set of old fuel level sensors from the aircraft we are considering.  If the part numbers for the senders match the aircraft they are on, we are good to go.
  • Ideally this aircraft should have a strong user base with an owner base that demonstrates their willingness to embrace new technology with their pocketbook.
  • Discuss the compatibility with commonly installed MFD components or instruments.  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.
    Old Cessna 177 Stewart Warner and Leigh Fuel Sensors 
  • 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 prototype sensor with our best guess for geometry.
Cessna 177 Cardinal Fuel Tank - Internal Shot
  • 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.
Fuel Tank with Prototype Sensor Installed 
  • 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 -
Varying fuel tank angles caused by imbalanced fuel filling - filling one side before the other
or 
The angle of the ramp typically created to drain water from the ramp surface.
Both of the above have an effect on apparent aircraft fuel level from simple visual observation.  
  • A confirmation of entered fuel level and actual fuel level when the aircraft is in stable cruise flight may allow the pilot to correct for an erroneous starting fuel level value. 
  • The final result is a happy customer with a new fuel sender design that has hundreds of data points to describe the fuel tank contents on their new MFD display or instrument.
Note:  While this seems to be an involved procedure - accurate fuel display on an aircraft requires this level of detail otherwise you might not get the information you need.