Lightning Safety - Fuel Senders

Lightning Safety - Aircraft  Fuel Quantity Senders  

It is required to provide in-flight lightning protection in all types of fixed/rotary wing and powered lift aircraft of conventional, composite, and mixed construction and their electrical and fuel systems.  The design of adequate lightning protection for aircraft fuel systems is one the most important lightning protection tasks to be accomplished. 

Government airworthiness certification requirements stress fuel system safety because this system has been responsible for most lightning-related aircraft accidents. 

Elements of the fuel system are typically spread throughout much of an aircraft and occupy a significant amount of its volume They include the fuel tanks themselves, associated vent and transfer plumbing, and electrical controls and fuel quantity instrumentation. 

Careful attention must be paid to all of these components  if adequate protection is to be obtained. The main objective of fuel system lightning protection is to keep ignition of fuel from destroying the aircraft 'during a strike. This goal is quite challenging because thousands of amperes of current must be transferred through the airframe when the aircraft is struck by lightning and a tiny spark of less than one ampere may release sufficient energy inside a fuel tank to ignite the fuel vapor and initiate an explosion. 

There are 4 methods of preventing aircraft fuel hazards from lightning:

1. Containment - The expansion due to the explosion is contained without structural issue.
2. Inerting - Introducing nitrogen into the fuel tank. 
3. Foaming -  Fuel permeable foam like are cars 
4. Eliminating Ignition Sources

CiES Magnetic Field Fuel Quantity Design embraces #4.   CiES simply eliminates the wiring and the wiring hazard from the fuel volume.    The wiring and fuel sensor element are kept completely out of the fuel volume, if the sender is mounted to the tank surface.   

This methodology eliminates any electrical ignition source from the fuel volume.  

While this issue has not proven to be an issue with some fuels namely AVGAS - lightning induced ignition of fuel tanks containing gasoline is not an unknown phenomenon as demonstrated below in Ohio

So while lightning indirect and direct effects are addressed for the wiring.   Induced effects become paramount for good design.  

Arcing and sparking within the fuel vapor space of a fuel tank is one of the primary concerns of the fuel quantity system designer. The distinction between arcing and sparking is worth reviewing. Arcing is the result of current through the interface between two conducting materials which are making limited electrical contact. Such a condition may exist at the interface of two moving metal components like the CIES rotor and pivot or between the arm and the internal tank surface as shown.

A spark, on the other hand, is an electrical die-charge resulting from a difference of potential across an air gap or along a dielectric material. This condition may exist, for example, in the CiES fuel sender as the metallic components are anodized and teflon impregnated for corrosion protection.  Current through the tank may result in difference of potential between these components. 

By insuring conductivity is maintained throughout the fuel quantity sender this hazard is mitigated.  CiES utilizes clever details to maintain corrosion protection but also to insure induced charges dissipate harmlessly to aircraft grounding structure 

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

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.

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.

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

Does Airport Density Affect Aircraft Fuel Starvation Rates

One of the aircraft owners user groups postulated an interesting question.  

Does the density of airports affect the number of fuel starvation events? 

Are you more likely to push the fuel envelope if you feel safer knowing there are many suitable 
alternatives to land and refuel,  and do pilots take advantage of those opportunities. 

As always when it regards aircraft fuel,  it is always an interesting question and not a lot of concrete information available.  Most of what is written about aircraft fuel level is unfortunately anecdotal.

So armed with a fuel starvation/ exhaustion dataset gleaned from the ASRS (Aviation Safety Reporting System)  I set out to see what actually would shake out if we looked at number of airports per sq. mile and fuel related aircraft issues and put it on an overlay of the USA.   Darker States are worse off than Lighter States.  

Generally speaking - pilots seem to be more careful out West where airport density is lower.   

I did evaluate the per state fuel starvation statistic by number of aircraft per state, but as aircraft quickly transition from one state to the next, I didn't believe it held much merit to display.  

What does show up in many graphs of this type is that Wisconsin and EAA draws a number of pilots from around the USA and a fair percentage tend to inadvertently stay longer than planned. 

Stealing an safety idea from the Cirrus Pilots Association  

Fuel Early, Fuel Often  

Reliability and Continuous Improvement - CiES

Non-Contact Fuel Level Measurement

Recently we ran across an article in the Cirrus Owners Magazine  - Cirrus Pilot 

The article talks about the Continuous Improvement Process that Cirrus Aircraft utilizes in its aircraft design and production to improve reliability.

This article it discusses the complete paradigm change CiES made to aircraft fuel level measurement and Cirrus Aircraft's customer satisfaction with our non-contact fuel measurement technology.

As the article states - CiES Brought a Whole New Approach to Aircraft Fuel Level.  

An approach that changed fuel level reliability, so significantly, that it is no longer necessary to question your aircraft fuel level indication.

Take Your Fuel Level Indication to Un-Charted Territory and  Embrace the Reliability of the CiES Non-Contact, Magnetic Field, Fuel Level Solution

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  

A Universal Aircraft Fuel Sender

A UNIVERSAL FUEL SENDER

When we started manufacturing fuel level senders,  we had a specific customer in mind.   

In order to maximize our customers benefit for this technology, we made this sender nearly exclusive for that customers application. 

We received quite few inquiries for this fuel sender and most of them related to will it interface to our existing system.  

Sadly because we had tailored the sender to a particular aircraft and avionics interface,  we had to turn good business away.  

So step forward 3 years nearly to the day,  we had an opportunity to reinvent the fuel sender product and add new features:

First:   We have utilized a unique circuitry design to create a universal output:
                         - We can supply:  Resistance
                                                      Voltage
                                                      Frequency 

Second:  We can supply a  Fuel Temperature Output.  This feature is helpful for Jet A applications  where Pounds Fuel is the unit of measure.

Third:  We have supplied a pigtail to allow installation in tight spaces and flexibility in the Fuel Sender connection. 

We are trying to remove any barrier for you to have a more reliable technology for fuel level in your aircraft.

Contact Us for more information.

5000 Aviation Fuel Level Senders

After two years of production we have crossed a major milestone.

There are 5000 CiES Inc Fuel Level senders in the field or more appropriately, in the air.

What does that mean for our customer base or our potential customer base?  

The CiES Magneto Resistive Fuel Level system is proven and a good solution for fuel level measurement in a variety of applications.

We have proven the concept in what may be the harshest environment for fuel level measurement - aviation.  By proving ourselves in the aviation world we literally can take this method anywhere.


Our quality is phenomenal - out of the 5000 units in the field we have yet to take one out of service.
   
Can you say the same for your fuel level solution?

Video of the Cirrus SR22 Retrofit

Post by CirrusPilot.

If You Trusted Your Aircraft Fuel Gauge?

How would you operate your aircraft

If you knew, at all times, how much fuel you had.

Hard to imagine, isn't it ?

Did you ever have that feeling that you might have put in the wrong fuel starting amount?

Did you really see fuel wash over the tabs?

Doubts about fuel level can creep into any flight.   

The statistics of fuel starvation, fuel exhaustion and fuel related loss of power events bear that out.  

But it is interesting to see that with a change in technology for fuel level reporting to Magneto Resistive Senders.

Some pilots are finding an opportunity to operate differently.

CirrusPilot

Commenter Dialogue:

I'm always surprised you do not fly your 22t topped off, were you taught to fly with minimum fuel? Maybe it's a West Coast thing, but my Cirrus SR22 is always sitting full and I fuel it every time it is at home.

Response:

Plane is hangared. Full tanks are heavier and the performance is affected. I carry 20g extra to a location like Vegas.

New Advertisement - Cirrus SR22 Retrofit

Parody on a Recent AOA Advertisement

AeroviePilot iPad Application Demonstration

USA Today "Unfit for Flight"

There has been a lot of discussion in the aviation community about this 3 Part Expose' Series in      USA Today - Most of our aviation community agree that - we should strive to make aviation safer.  Most of us on this side of the fence,  also agree that the condemnation of manufacturers in this industry was - just a little slanted.  I happen to know several of the players and the other side to many of the examples and lawsuits presented.   It is not as cut and dried as the articles suggest.

Mr Bertorelli - who I respect as an aviation journalist and pilot - made several good points in his Blog  As most people are aware - Aviation is the "most regulated business in the world".  In this industry we laugh at drug and medical device companies - because they have it easy.    In this environment how could an outside news agency find fault with our industry.    Given the economics of this particular business,  it isn't profitable to do a bad job.   Paul stated all of this in his blog very clearly:

There’s wide agreement that over regulation has had a hand in getting us into this mess, so further regulation — of manufacturers or more stringent training requirements —won’t get us out of it.   The entire community just doesn’t have the stomach for it. And neither do I, frankly.  Not to mention the utter lack of any economic engine to drive it all.

I was however struck today with one of Mr. Bertorelli's responses to this safety issue - and because an element of the rebuttal involved a segment of the aviation industry that I have become quite familiar.

At this point, we work on fuel level systems in aviation and most recently the automotive industry.

We have a unique but very narrow viewpoint.

GA Safety: All Heat, No Light

Excerpt from Paul Bertorelli's Blog 

As a refreshing change, the USA Today report almost tried to cast pilots as steely eyed but hapless victims of shoddy manufacturing and outdated aircraft designs. Were it only so. None of us have to look in the mirror to know that although out-of-the-blue mechanicals do cause accidents, preventing every one of that category wouldn’t change the accident rate much.

Even in some of the egregiously poorly prepared reports, the pilot obviously did something stupid—like flying into bad weather, overloading the airplane or, a perennial favorite, running the tanks dry because the fuel gauges aren’t accurate.  

That last item is a cultural thing in which automotive knowledge contaminates aviation thinking. It’s like that GEICO commercial; everybody knows the gauges aren’t accurate and we have means to work around this deficiency. 

Using a crash as a means of highlighting it seems somehow unsporting. Yeah, the stupid gauges should work, but no, they don’t.  So buy a totalizer or learn to use a watch.
But unless you, as the owner or pilot, take personal responsibility, your 35-year-old Cessna 172 is not going to be fitted with more accurate fuel gauges. 

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Unfortunately neither the NTSB or FAA equate "Bad Fuel Gauges" to Fuel Exhaustion,  but it is interesting that Paul does state this in his blog.  It is quite common to report to the NTSB or FAA after an accident that the fuel gauges are not accurate in your damaged aircraft.  There is no consequence to those statements.  If your flight plan did not indicate average fuel burn - look out.  

I also agree that fuel level is a cultural thing in aviation - I am not familiar with the GIECO reference Paul equates - but fuel level in automotive applications is barely adequate, the website tankonempty.com illustrates this very well.  The issue in aviation, is that for most small aircraft, the fuel level system was taken from a ground vehicle system, think automotive, tractor, truck - This system, was barely adequate for an automotive application as illustrated by the website above  - and this system really struggles with fuel quantities that are 3 times larger, and the fuel and vehicle movement that occurs in aviation.

When we talk to people outside aviation - and we state things like Paul's statement "Yeah the stupid gauges should work, but no, they don't"     - they look at first puzzled and then to a each non aviation person we have stated this quizzes us back "Don't small aircraft run out of fuel"  Yes they do. 
   The National Highway Transportation and Safety Administration - NHTSA in a recent automotive recall for bad automotive fuel fuel gauges on Chevrolet Trucks stated that the there was an obvious safety issue with having bad fuel gauges  - specifically from the recall announcement:

"If a customer runs out of fuel without any warning from the fuel gauge, it will cause the vehicle to stall and increase the risk of a crash, the company said."

In aviation, as Paul Bertorelli stated for fuel level  - "we have work arounds". 

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As I am focussed on a small aspect of the aviation safety issue - and this is seemingly the common aviation response to a significant issue. 

Because from where I am sitting -  maybe the pilot of the 35 year old Cessna 172 should at the least have the fuel gauges checked and calibrated at annual. 

If the gauges are too far gone - he should have the maintenance facility send in a Service Difficulty Report to the FAA - let the Feds know we have an issue out here in the field.   Let's quit making excuses or work arounds for equipment that should and by law be required to function correctly. 

I think we as a community should start questioning these common assertions and take off the cultural blinders.  

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I think we all want to make aviation safer - including USA Today.

Fuel Gauge INOP for initial CFI Check Ride

A Posting from Pilot Instructor Forum 

Hi all,

I am taking my initial CFI check ride this weekend. I went out to fly the airplane (C-R182) from the right seat to practice some maneuvers before the check ride. But, I realized the left fuel gauge is indicating zero no matter how much fuel is in the tank.

It sounds to me like the issue is somewhat controversial. I've heard "fuel guages only need to be accurate when the tank is are empty" and I've also heard that per 14 CFR 91.205 (b) 9 the airplane needs to be equipped with an operable "Fuel gauge indicating the quantity of fuel in each tank".

I tend to agree that the fuel gauge needs to be operable, but there's no time to get the fuel gauge repaired before the check ride. Any advice?

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Yes, per §91.205 a fuel guage for each fuel tank is required for day / night VFR and IFR flight is required to be operational.
You could argue as others did that it only has to “correct” when on empty and I would agree but it has to read something. The other way of looking at it is that the fuel guage has to read something other than empty when their is fuel in the fuel tank.
If your airplane has an approved MEL, it might be allowed to be inoperative provided you verify the amount of fuel in the tank, but for your initial CFI test do not take a chance of busting because of an unairworthy aircraft.

---------------------------------

Remember the Tomato Flames acronym.  F is for fuel gauge.  You must have a functioning fuel gauge.  The acid test is safety.  Do you feel safe flying an airplane with an inop fuel gauge.  I would tend to want to get a ferry permit to get it to a repair facility, or better yet, get it fixed where it sits if you can.  There are too many fuel exhaustion accidents (preventable) per year to take a chance like this.  I know this sounds a little over-reaching, but as a CFI, you are the prime example to the flying public.  To show your willingness to take a chance on an inop fuel gauge sends a dangerous example to your potential students that the Pilot Examiner or FAA Safety Inspector should flunk you for.  Get it fixed then take your exam.

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“I tend to agree that the fuel gauge needs to be operable, but there’s no time to get the fuel gauge repaired before the check ride. Any advice? ”Seems like a no-brainer to me.  You have an unairworthy airplane you’ve been training in and you’re contemplating taking a checkride in it?  for a CFI? BTW, Part 23 says the fuel gauge must be *calibrated* to read 0 when there is no usable fuel in the tank.  Being calibrated to read 0 doesn’t mean that this is the only indication that needs to be accurate.  All scales must be calibrated at a certain weight, and the error increases the further away from that weight that you get.  Even so, the error is usually required to be within a certain range.  Part 23 doesn’t publish that range, but likely there is one.  Someone I know has requested an LOI on the topic from the FAA’s General Counsel’s Office, but it won’t be available until October.

Note: That letter was not published by the FAA General Counsel 
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In reading the above responses a couple of thoughts come to mind.  While by regulation the fuel indicators must function, relying on them for anything other then an indication of possible fuel present is more dangerous then not having a guage at all.  Our flight school had 36 aircraft and there wasn’t a guage in any of them that was even close to accurate.   Many times a student pilot or CFI would request fuel for a plane by reading the guages (without comfirming visually) only to find the tanks topped off.   And conversely, taking off with what they thought were full tanks only to land an hour later with one tank dry.The comment:” There are too many fuel exhaustion accidents (preventable) per year to take a chance like this.  I know this sounds a little over-reaching, but as a CFI, you are the prime example to the flying public.  To show your willingness to take a chance on an inop fuel gauge sends a dangerous example”

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While I wholly agree with the assertions that physically checking and monitoring the fuel quantity using known values is the best practice, the reg is very clear about what is required to be working at all times.  If you fly with a fuel indicator broken (which it clearly is), then you are essentially shooting yourself in the foot.  Yeah, you might get away with it, but then again, you might not.Also, in regard to MEL’s, 91.213 is very specific that any equipment required to be in operation by regulation (such as 91.205) by default can’t be included among the inoperative equipment in an MEL.