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

Beech Baron Digital Fuel Sender Retrofit Part 6

Beech Baron 58 Fuel Level Senders

CIES Baron 58 Fuel Quantity Senders

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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. 

Beech Baron Digital Fuel Level Sender Retrofit - Part 4

Beech Baron 55 Fuel Level Senders

We have now digitized the Baron 55 Senders.  For the Baron 55 we have gone ahead with part production for top mount senders and have established the arm lengths to complete this design.   

As we produce the arms in house -                                                                                                                                                    This gave us the shortest time to achieving a TSO Baron Fuel Sender for our customer.

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

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 accurate fuel level.

Stay tuned for further updates and pictures.

Beech Baron Digital Fuel Level Sender Retrofit - Part 3

Beech Baron 58 Fuel Level Senders

We have now digitized the Baron 58 Senders.  For the Baron 58 we have gone ahead with part production for top mount senders and only needed to establish the arm lengths to complete this design.   As we produce the arms in house - this gave us the shortest time to achieving a TSO Baron Fuel Sender for our customer.

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

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

One of the interesting items that came up in investigation is that every legacy Outboardd bottom mount Beechcraft Baron 58 Fuel Sender has a seemingly factory grind mark on the housing and screw  - Clearance ?

Stay tuned for further updates and pictures.

Beech Baron CiES Magnetic Fuel Level Sender Retrofit - Part 1

Beech Baron 55 Fuel Level Senders

We received a set of Beech Baron fuel level senders yesterday.  In the coming days we will quantify the major characteristics of these senders like the arm length and position so that we can make new CiES Digital Magnetic Field Senders to accurately read the volume in the Beech Baron fuel tanks - Both the Main and Aux.  

Stay tuned for further updates and pictures.

Beech Bonanza Fuel Level Senders

Beech Bonanza Fuel Level 

CiES is rapidly expanding the number of aircraft that can utilize our Fuel Level Sender technology.   Today we delivered the first set of Beech Bonanza / Debonair fuel level senders.   

This set replaces the Beech original equipment Leigh senders still found in the aircraft.   The old senders had long ago given up on providing accurate fuel level. 

These new fuel level sender utilize non contact, wear free magnetic field technology to locate the float in the tank.  The technology found in CiES Senders is similar to that in your cell phone for it's compass operation.  But instead of pointing North in the compass example, the sensor in the CiES Sender points to the float and to an accuracy less than a 1/4 of a degree.  It does this accurately and repeatably.  You trust your compass to always point North - you'll trust this sender to always tell you how much fuel is in the tank.

The old rusty senders depicted in the pictures utilized continuous wearing potentiometers typically found in legacy General Aviation fuel tanks.  

Potentiometer senders have an in aircraft life of approx. 10 to 12 years before replacement or rebuild.  

You should'nt fly with fuel level senders that are 30 to 40 years past their functional life, Now you don't have to 

Beechcraft Bonanza Fuel Level Senders

We just completed our first set of Beechcraft Bonanza Fuel Level Senders


These magnetic field senders are for Tip tanks produced by a popular Beechcraft modification facility.

We are starting to branch out into multiple applications in the aviation field with our magnetic field fuel level senders, from turboprop, helicopter or piston aircraft. 

Our technology allows for a nearly plug and play solution for legacy resistive fuel level sender installations.

What started as a Cirrus Aircraft only application for fuel level sensing is slowly starting to spread across the aviation field.  With over 10,000 senders produced to date,  CiES is "The Word" in aviation fuel level sensing.

Ask us about your application? 

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.

Learn more on the CIES Inc Website

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.

Aircraft Fuel Management - Down Under - Civil Aviation Authority

Sometimes it's helpful to look at how other countries address a similar problem.  The below excerpts come from the New Zealand Civil Aviation Authority.

Determining Fuel Available

Accurately determining what quantity of fuel you have on board is important. Assuming the fuel required for the flight has been calculated correctly, it should be a simple matter of uplifting it and completing the flight with a comfortable margin to spare.

It is good practice to check the fuel available before flight by at least two separate methods (in Australia, this is a legal requirement). We can do this by referring to the fuel gauge(s), loading a known quantity and, in many aircraft, by dipping the tanks. There are a number of considerations that should be borne in mind when determining the fuel available.

Unusable/Usable Fuel

Understanding the difference between the terms usable and unusable fuel is important in determining the fuel available for flight.

The unusable fuel is the quantity of fuel that cannot be used in level flight. It is the quantity remaining in each tank after the tank outlet becomes uncovered in level and balanced flight. The amount of unusable fuel can vary considerably from aircraft type to aircraft type – refer to your aircraft Flight Manual for specific figures. The fuel tank outlets on some aircraft types are very susceptible to becoming un-ported during prolonged unbalanced flight, which eventually leads to fuel starvation and engine failure.

Extreme care must be taken to ensure that the unusable fuel quantity is not included in the fuel available, as it can equate to as much as 20 minutes extra flying time that you don’t actually have.

It follows that the usable fuel is the quantity of fuel available for flight planning purposes. This is the only figure that should be used when calculating fuel endurance. Most dipsticks are calibrated to read the total fuel quantity in the tank, which means that the unusable fuel must be subtracted to determine the fuel available for flight. Care must be taken when converting between litres, and US or imperial gallons. Calculations should always be double-checked.

Fuel Gauges

Most fuel gauges read reasonably accurately, and if they don’t, they must be fixed. Gauge accuracy can easily be checked before the flight by dipping the tanks (if that is possible) and comparing the figures with the actual gauge readings. Any discrepancies must be allowed for until the problem can be fixed.

Be aware that fuel gauges can stick or fail in flight, sometimes in a subtle way, so don’t rely on higher-than-expected readings which seem at odds with expected consumption as the flight progresses. Also, in some common aircraft types, fuel gauge indications will vary widely according to the direction and degree of any slip or skid.

Some aircraft have tank designs where a dipstick reading can’t be obtained at certain fuel levels, so the use and accuracy of the fuel gauges becomes even more important to the pilot.

Cirrus Aircraft Factory Fuel Level

We have been supplying Cirrus Aircraft fuel level senders for over a year.  There have been no issues or in-field replacements.  Now that the senders have proven themselves day in and day out and showing excellent reliability and repeatability.  We can now start to exploit the advantages accurate fuel level can provide.   

In the Cirrus Aircraft Facebook post yesterday - one of these new features came to light.  

Cirrus wrote the following:

Since spring of last year, our aircraft have come equipped with fuel level sensors that read accurately at all levels. In fact, they are so accurate that we were able to integrate a fuel imbalance message on the PFD in Generation 5 aircraft. The fuel level sensors in most of our competitors’ planes only read accurately when the fuel tank is empty or full. For more on the astonishing innovations that make Cirrus an industry leader: 
http://bit.ly/YZO6rT

Better information =  "informed"  decisions

As always when you forget,  a careful reminder will get things back to normal

Aviation Fuel Level

Traditional Aircraft Fuel Sender 

Why don't my fuel gauges work?

Let us cover a few basics  

• Aviation industry has utilized level senders from other applications
• Aviation is not the largest market or the most financially rewarding for a dedicated fuel level sensing solution.

• Aircraft fuel tanks are larger than those for most other applications. 
• An aircraft carries more fuel.

• An aircraft has three degrees of motion freedom 
• The liquid fuel is free to move about.

There are other factors.

• Why not design a new system 
• Fuel Level Intellectual Property is hotly contested territory (a patent minefield) 
• A new aviation design must avoid other patents 
• The market share is small
• The perceived liability - Top 5 aircraft incident issue

• Fuel Level in Aircraft needs to be "Intrisically Safe".
• Explosion Proof 
• Limited Spark or Heat Energy in the fuel tank. 
• Non - Contact "The best solution" for Intrinsic safety is the hottest IP in Fuel Level
• Required for multi fuel and hybrid vehicles
• Required for vehicles with long term fuel storage - i.e. Boats
• Required in LNG / LPG

------------------------------------------------------------------------------------------------------------Fuel sending works in my car.

• Automotive fuel tanks are smaller
• What would be adequate for a resolving 16 gallons of fuel has difficulty with 3 times the volume.   
• If you have a boat - this is also an issue as you are well aware
• The variable resistor technology used in automotive applications doesn't scale well
• The variable resistor cards used,  allow 60 degrees of travel  - a good resistive card for aircraft or boats would require minimum. 180 degrees or more.

• Relatively stable fluid motion 
• The automotive sensor is exposed to some fluid motion but overall less. 
• Aircraft fuel can remain quite stable - however turbulence will creates concentrated fluid motion.
• This motion wears the resistive trace - so inadequate resolution of the variable resistor is now faced with increased wear.  From bad to worse.

• The basic requirements 
• Standard aircraft fuel gauges are calibrated only for the full and empty position.
• Caveat - new automotive systems are calibrated to the tank - great improvement
• Caveat - new aircraft MFD's allow tank calibration - Aerospace Logic, JPI, Garmin

• Almost daily use  
• The automotive sensor is continually washed with new solvent at every filling and fuel fills are more frequent. 
• Aircraft fuel can remain in the tank for long periods - it is designed to do so - however impurity buildup on the variable resistor are common at a fraction of usage time of the automotive application.
•  it is quite common to have your aircraft senders ultrasonically cleaned

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Propane Level Gauge

New requirements for intrinsic safety for all aviation fuel level systems 

• The general aircraft industry found that they could utilize a commercial off the shelf, patented float sending unit from the propane industry
• This met the new safety requirements and directly replace a float level legacy system.

• A Non- Contact solution - the resistance card was removed from the tank environment.
• Shock inputs from turbulent air can however de-couple the matched magnetic drive and the the gauge will take a set but in-accurate reading or drift back to the correct reading.
• Suffice to say - Propane Tanks were not meant to fly

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Aircraft Capacitive Sender Ad - 1948

Alternatives  - 

Capacitive Senders -

Conceived in the Late 1940's this aircraft fuel sending system set about to address the two most common issues presented above - fluid motion and resolution of the larger fuel quantity.   

These are the most widely used in aircraft above 12,500 lb 

Capacitive Sensor Benefits 

• Immunity from fluid motion 
• Greater resolution of the large fuel volume 
• Shapable to the fluid volume - tailored to the tank volume.

Capacitive Sensor Issues

• Difficult to Prove Intrinsic Safety
• The definition of the sensor is to utilize two metallic or conductive elements in the tank 
• The intrinsic safety requirement must be met with increasing the complexity of the system.
• It is a spark in the capacitive sensor that initiated the explosion in TWA 800 fuel tank. 

• Moisture Rejection
• An aircraft fuel tank breathes on ascending and descending - moisture in the air is constantly brought in contact with the fuel.  Sealing the tank is not an option.
• As the capacitive utilizes the fuel contents as an integral element of the level reading - this variable is very difficult to manage.

• What's in the tank - matters a great deal 
• Fuel must be:
• uniform 
• moisture-free
• stable and uniform temperature
• contaminant free
•  to give a consistent and accurate fuel level indication 

When you review the system above - the capacitive sender solved several issues with fuel level indication, however it brought a few of it's own limitations along for the ride.

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Ideal Aircraft Solution Characteristics

• Non Contact - New FAA Requirement
• Intrinsically Safe - 
• The alternative is proven safe electronics in the fuel
• Immune to fuel contamination

• Unaffected by Fluid motion 
• No wear items related to fuel level reporting

• High Resolution 
• Address the larger quantity of fuel in aviation systems.

• Simplicity 
• The best aviation solutions eschew complexity where a simple system provides equivalent benefit.

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CIES Inc AMR Fuel Level 

Float Based Level Sensing - Retrofits or directly replaces most units in the field

• Non Contact 
• No - Safety Issues 
• No - Fluid Contamination
• No - No moisture or fuel quality issues

• Immune to Fluid motion
• No wear of fuel level reporting system

• Resolution 
• Digital output
• More fuel level information 
• Integrity of the level signal
• Interfaces to modern avionic solutions
• Ability to output fuel temperature - Lbs fuel. 

• Simplicity




• No complexity required
• On the platforms we have been applied - exceed it's requirements

CIES Inc AMR  A sensor that was designed for and patented with the aviation industry in mind, but suitable for all high value applications.

Aerospace Logic - Cirrus Design Retrofit

In creating a new fuel level system for Cirrus Aircraft we kept in the back of our mind  the opportunity to provide this technology to legacy Cirrus Aircraft as well as other aviation applications.

Aerospace Logic was the obvious choice - 

We chose their 200 series unit over other 2 1/4 instruments as Aerospace Logic has created a quality and sunlight readable  display with a clear and concise level indication.

More importantly, Aerospace Logic like CIES saw accurate and reliable fuel level indication as a valuable instrument in the cockpit.  Aerospace Logic was hampered in achieving it's goals for fuel level indication by fuel level senders that were previously available to the aviation market.  CIES Level senders with our new and patented technology completely changed the fuel sender game.

You will note that a digital value of fuel is displayed below each quantity gauge.  This gives an unmatched accurate calculation of quantity in each tank.

Aerospace Logic has worked with us to incorporate appropriate warnings that a quality fuel level indication system can provide.

Note:  The upper display is indicating a fuel "Imbalance Condition"
and the flashing Amber bar is indicating you have exceeded the POH recommendations for fuel level imbalance. Switch to the flashing AMBER tank.

One of the most important characteristics of the Aerospace Logic Display is the trend graph featured on the second page.  This provides graphical information of fuel level over time.  The use of the displayed trend data makes it easier to manage fuel in a single engine aircraft.

Most importantly,  Aerospace Logic was willing to work with CIES in developing a display unit that would allow a digital interface between the display and fuel level sender.

Aerospace Logic and CiES Inc. look forward to pilot response for this system.

http://www.aerospacelogic.com

Digital Fuel Sender Now Certified

Digital fuel sender now certified

The AOPA Press Release came out today
It seems to be difficult to find, but it is on the web

The basic concept is ....


When we have specific aircraft (or aircraft type) information
and we demonstrate that the system is compatible to Transport Canada ... Flight Test
or operation under 337 Field Approval

We can add those aircraft onto the blanket AML STC owned by Aerospace Logic.

We believe after we demonstrate on several aircraft types that this is simple modification and installations are straight forward  additional aircraft models will fall into place.

TSO C55a Approved Fuel Float Level Sensor

CIES Inc has obtained FAA TSO Approval - C55a - at the most rigorous standard for it's line of float based digital fuel level senders.

Its official we now are producing a line of TSO'd Fuel Level senders applicable to most aircraft below 12,500 lb gross weight. 

This effort provides a real alternative to the old Stewart Warner  senders long out of production for current General Aviation Aircraft fleet.

We are working with every major manufacturer to incorporate our senders as original equipment.