We've taken on a new look

Bad Aircraft Fuel Level Indication Can Lead to Aircraft Fuel Starvation.

Really Where's your Proof 

Yes I know you have read every publication put out by AOPA and the FAA and they clearly say fuel level indication is clearly a pilot error issue.  In NTSB reports they have a rubber stamp that reads like the following :

"The pilots improper pre-flight and inflight planning, which resulted in fuel exhaustion."

What most in the general aviation community opinion on this issue is referred to as Fundamental Attribution Error.  (FAE) This is where we naturally blame people, even when circumstances or conditions are the primary issue.  

Last week I wrote a blog with the intentionally provocative title: "Let's Legislate Accurate AIrcraft Fuel Level"

For this I received the expected typical responses below: 

"How about we simply look at the number of people that have fuel related accidents and see if they did a proper preflight ...which...since you keep going by FAR's is required. If they didn't do a preflight correctly...they are poor pilots...and if they are poor pilots...gauges won't make a difference. You can't save people from being stupid"

"So, how much of this is lack of awareness, poor training or just laziness I do not know. But this is one of the most preventable accidents out there that keeps happening on a regular basis. I am not convinced an AOPA video will change that.  That is the real crime. They are still happening twice a week and none of them have to."

You would actually expect this pilot response to the provocative inquiry.   In looking at this as a pilot cultural issue or a FAE  the concept of  "Just World Phenomenon" features prominently.  This is the belief that people get what they deserve and deserve what they get.   


Unfortunately, the just-world hypothesis also results in a tendency for people to blame and disparage victims of an accident or a tragedy.  It is actually a protective strategy of the mind, providing mental separation from those kind of pilots that run out of fuel.   It won't happen to me, I am not like one of those pilots.

Sorry - These are random events and they happen to good pilots - I have a files and files from Transportation Boards across the world - you are not immune.  You have a doppleganger who was just as careful as you are and ran out of fuel in their aircraft.   I am sorry to burst the protective bubble.

What appears to happen in General Aviation is that, blame for fuel starvation, falls squarely on the those pilot shoulders .  This appears to be cultural phenomenon among pilots of all types.  The primary message we hear is that education will cure the miscreants, those bad pilots that will always get into trouble.

Very rarely do we delve into the situational factors of the fuel starvation issue at hand.  Our cultural bias doesn't allow that possibility.

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Fuel indication in aviation is loathsome at best - it is not a deep dark secret that most aircraft fuel indication systems are marginal from the start. 

 When you compound a marginal system with poor or no maintenance,  you can make a general statement that a functionally inoperative fuel gauge is common place in aviation.  

This is illustrated by responses from a General Aviation News inquiry as to what pilots felt about general aviation fuel level indication.

"Maybe they’re also more in the habit of keeping an eye on the clock in flight, even sneaking the occasional glance at those notoriously inaccurate fuel gauges." 

"Airplanes are legendary for having inaccurate fuel quantity gauges" 

"These devices are notoriously inaccurate, showing empty when there are gallons left in the tank and showing full for the first 1/2 hour."

"Aircraft fuel gauges can be notoriously inaccurate." 

"Without a means of measuring fuel flow, you must rely on the aircraft fuel gauges or total time of flight. Aircraft fuel gauges are notoriously inaccurate (they are only required by the FAA to read accurately when displaying empty)." 

"Aircraft fuel gauges have a well-deserved reputation for being unreliable and the FARs only require that fuel gauges read correctly when they are empty!" 

"Second, as others have said aircraft fuel gauges have historically been
poorly designed and grossly inaccurate.  Many will indicate something significantly different in a climb vs a descent and there are some airplanes with fuel gauges that are designed to read full until a substantial amount of fuel has been consumed." 

"Don’t bet your life on your fuel gauges, visually check the fuel level by “dipping” all tanks. Some aircraft models have notoriously unreliable fuel gauges." 

"All light aircraft gauges are notoriously, infamously and reliably, unreliable." 

"Sounds great in theory, but I have not yet seen an accurate Cessna fuel gauge, Ever. A fairly expensive AD would be the only thing that would ever change that."

I don't think a statement that  "Aviation fuel level indication could be improved" would fall very far from the mark. 

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Better fuel indication will lead to better decisions and appropriate warnings in aviation.  

While it seems obvious to a layperson

Strangely, Thats not the popular opinion in GA.  But here is the proof. 

EASA (European FAA) - In a Transport Aircraft study for revisions to required powerplant instruments.  EASA showed that better fuel indication would have improved the result of the 65 incidents and accidents in Transport AIrcraft - well over 70% of these accidents/incidents could have been avoided.  Transport aircraft are not GA, but it is the same mode.

CASA (Australian Civil Aviation Authority) Requires that aircraft fuel Indication in Australian aircraft meet a performance standard, every 4 years.   The reasons cited are improving the fuel starvation incident and accident rate. 

TSBC (Transportation Safety Board of Canada) Makes findings of faulty fuel indication a factor in fuel starvation events.  They point to the wide use of fuel sticks as an indication that fuel level reliability could be improved in aviation

 The fuel quantity indicators on this type of aircraft were not reliable. As a result, the pilot could not be sure of the quantity of available fuel in the left tank during flight.

Tests on the components of the fuel level indication system established that the only time the fuel level in the wing tank was shown correctly was when the tank was empty 

The Bell 214B and Bell 205 flight manuals be modified to provide information regarding the inaccuracy of fuel quantity indications, thereby allowing pilots to make informed decisions in the event of a loss of fuel boost pump pressure. 

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Cognitive Bias 

While these two points are associated with the same system and appear plain as day 

1. General Aviation Aircraft have inaccurate fuel level indication.
2. General Aviation Aircraft are prone to fuel starvation and fuel exhaustion.

A general aviation pilot won't recognize those statements as connected. 

Why: 

Anchoring Bias -  The tendency to rely too heavily, or "anchor", on one trait or piece of information when making decisions (usually the first piece of information that we acquire on that subject.

Pilot's are told to never trust the fuel gauge on the first training flight. 

Availability Cascade A self-reinforcing process in which a collective belief gains more and more plausibility through its increasing repetition in public discourse (or "repeat something long enough and it will become true.

Bandwagon Effect The tendency to do (or believe) things because many other people do (or believe) the same.

AOPA, FAA continually tell us that we need to use proper pre-flight procedure including sticks.

Confirmation Bias The tendency to search for, interpret, focus on and remember information in a way that confirms one's preconceptions

Aircraft fuel gauges only have to be accurate at zero 

You're only interested in selling senders  

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I have a passion for European Sports cars of the 50's and 60's  and I was talking with a group of MG-TC owners.  The subject of fuel indication came up and the MG owner brought out his calibrated stick.   MG T Series cars don't have a fuel gauge, they have a warning light, and Old British cars being what they are the warning light isn't a trusted component or indication of anything of merit.    

I mentioned that small aircraft use a stick as well to determine fuel quantity.  There were lots of raised eyebrows and a few quizzical looks.    The very first statement I heard was.

  "I bet they run out of gas"

  followed by 

"They can't just pull over and check with the stick can they"

I told them the various reasons why,  and they asked if something was being done to improve that.  

I told them sadly no.  A pilot will go out today after purchasing a new aircraft and obtain a stick to measure their fuel.  

It's  startling commentary, that in aviation, we use fuel measurement methods and techniques to prevent running out of fuel that were common on minimal equipment British sports cars of the 40's & 50's.  

I hope it makes us think.

Cessna 210 Digital Fuel Level

CiES Added Another Aircraft Today 

So three new aircraft configurations this week in as many days.    This one was admittedly easy as it is identical to the Cessna 177 Design.   

I believe our greatest accomplishment this year is developing a methodology to add TSO'd configurations to our list.   

Our magnetic field design makes changes to fuel senders as easy as changing float arm length and an internal map profile 

Our technology for fuel level sending is eclipsed by no other method.  Magnetic Field is superior to both traditional aircraft Capacitive and Resistive fuel senders.  

Contact us to find out why we can make such a bold statement.

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.

Fuel Gauges: Do they Indicate Properly

Fuel Gauges: Do they Indicate Properly?

by Tom Bennett, Civil Aviation Safety Inspector, Aircraft Maintenance and Manufacturing, Prairie and Northern Region, Civil Aviation, Transport Canada

There have been multiple incidents of fuel exhaustion over the past few years. In the last issue of the Aviation Safety Letter (ASL), you read about fuel starvation due to improper fuel selector condition. In this article, I would like to talk about another common factor in fuel starvation incidents: fuel gauges that do not indicate properly.

Some incidents were very public, whereas most incidents went unnoticed with the exception of being listed in the Civil Aviation Daily Occurrence Reporting System (CADORS). Some incidents were directly related to poor fuel management by the flight crew(s); however a few came as a surprise to the flight crew, as the fuel gauge(s) still indicated there was fuel in the tanks. An accurate reading of the fuel gauge may have prevented many of these occurrences.

There is some confusion about the need for serviceable fuel gauges. This confusion is especially prominent in the general aviation world. As both an aircraft maintenance and manufacturing inspector and an enforcement investigator, I have heard statements like: “The gauges have never worked properly. I just keep track of time in my tanks,” many times.

Such a statement is contrary to Canadian Aviation Regulation (CAR) 605.14(j)(i), which states: “No person shall conduct a take-off in a power-driven aircraft for the purpose of a day VFR flight unless it is equipped with a means for the flight crew, when seated at the flight controls to determine the fuel quantity in each main fuel tank […]”. This regulation is then carried through in sections 605.14, 605.15, 605.16 and 605.18 of the CARs, to apply to all power-driven aircraft in all nature of flights (day/night visual flight rules [VFR]/instrument flight rules [IFR]).

Furthermore, many aircraft must have their fuel gauges working as per their type certificates. For larger aircraft, especially transport category aircraft, the fuel gauges can be deferred by means of the minimum equipment list; however, this usually involves using other measuring devices installed on the aircraft and making complex calculations.

A common factor in fuel starvation incidents:
fuel gauges that do not indicate properly

Recently, a commercial pilot was fined because one of his fuel gauges was not working while he was operating an aircraft. In this case, as in others, the fuel exhaustion caused substantial damage to the aircraft during the forced landing. The pilot applied to the Transportation Appeal Tribunal of Canada (TATC) to seek relief from the $750. The TATC upheld the Minister’s decision.

The Aviation Enforcement Branch has also sanctioned aircraft owners and operators for unserviceable fuel gauges found during Transport Canada’s oversight activities. The maximum sanctions for an infraction under CAR 605.14, 605.15, and 605.16 are $3,000 for an individual and $15,000 for a corporation. The maximum sanctions for an infraction under CAR 605.18 (IFR) is $5,000 for an individual and $25,000 for a corporation. Inspection, maintenance and repair of a fuel indication system seem less costly, in my opinion.

Another common excuse I hear is that the gauges have always displayed faulty readings or they are too difficult or expensive to calibrate. As an aircraft owner, if you rely on this flawed thinking you are exposing yourself to numerous risks. First and foremost, you risk running out of fuel. This can lead to personal injury/fatality and damage/loss to the aircraft. Second, you are exposed to regulatory action by enforcement (fine or suspension). I think we can all agree that none of these are pleasant outcomes.

For the aircraft maintenance engineers (AME) in this scenario, I have not yet seen an inspection where the functionality of the fuel quantity indication system is not checked. Be careful what you sign for on the inspection forms and subsequently, the maintenance release. Following manufacturers’ instructions for inspection, maintenance and repairs will never lead you astray.

Most pilots and AMEs are aware that any accident or incident results from a series of events; there is never just one cause. Anything we can to do tighten up against the possibility of an error is a step in the right direction. 

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Crown Copyright and Licensing, Public Works and Government Services Canada
Crown Copyright Clearance CCL FILE # 2011-33369
(c)Transport Canada, Aviation Safety Letter Issue 1/2011

AeroviePilot iPad Application Demonstration

Flying with an Inoperative Fuel Gauge - Legal or Not?

A Forum Dialogue about Fuel Gauges in Aircraft

I'm not sure where to post this so I guess I'll just post it here.

So today while pre-flighting my club's 172. I flipped on the master switch to check the fuel gauges. The right fuel gauge, indicated correctly. While the left fuel gauge however, was pegged on empty, even though there was full fuel in the left tank.   I know that fuel gauges should only be accurate when they are empty,  however under 91.205 it states that an operative fuel gauge(s) indicating the quantity of fuel in each tank has to work for a VFR day flight.

I asked the mechanic and he frowned upon me and gave me a lecture on how "fuel gauges should only read zero when empty blah blah," and that I could still fly the airplane.

Wearily I went and asked of one of the CFI's in the FBO and he told me If there is fuel in the tank and the gauge indicates zero or empty then its just an inaccurate gauge. If however, there is no fuel in the tank and the gauge indicates fuel, then that is an inoperative guage.

My question is, I am legal to fly? And what are you thoughts on this? I really dont want to be nit-picky about regulations on the airplane that I fly but, that is my name going into that logbook and I just didn't want to risk it.
Thanks!

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"You wrote this, so it should answer your question.  A further question could be: What is so critical about flying the particular mission you're seeking to (a pleasure flight), that would require you to go against the above? Especially if something were to happen on that flight that attracted Fed attention, related or even unrelated to the inop gauge? Would the club back you then?"

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"Tell the club to fix their stuff. There's no excuse for that kind of Mx laziness, and allowing it or making excuses for it with the "kick the can down the road" mentality they seemingly have, only perpetuates the problem."

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I'd say no, till it is either fixed or deactivated in accordance with the MMEL.The whole "it only has to be accurate at zero" argument to me is moot, It is currently at zero AND it is not accurate.   A broken clock is right twice a day.

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Dip your tanks and use those numbers in your calculations. Flt time x Rate of fuel burn = Gallons of fuel needed then add in your fuel reserves. I don't rely on what a fuel gauge in a 172 says.

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Personally, I wouldn't fly it. I certainly don't want to nitpick a plane apart, but the thing is, the fuel gauge isn't doing anything *at all*!

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I'd fly a plane that had a gauge reading "some fuel" when there was, indeed, some fuel in the tanks, and reading "empty" when it's empty.

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But having a gauge sitting on "empty" 100% of the time isn't acceptable, in my opinion. What's the point in even having the gauge then? Might as well just draw a picture of a gauge on the panel with magic marker, because it would be just as useful.

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Ultimately, I'd pull the "would you rent this plane to a fed?" question on them. If they wouldn't be willing to show it to a FSDO inspector, they need to fix it.

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Notice where the "zero" comes from. It is a guideline for when the fuel gauge must read zero. This is to keep manufacturers from using zero "total" fuel when calibrating the gauge instead of "usable". Other than that there is no mention of gauge "accuracy" in the reg

Also.
Notice the word "operable" in the Part 91 reg?Is the gauge in an "operable" condition if it is always reading zero? No.

Is the gauge in an "operable" condition when reading inaccurately? No.

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I've talked to the maintenance officer for the club and he said he will check it out tomorrow. But I'll definately crank her over and taxi her next time if it ever happens again. Thanks! For all your guys input, it really helps a lot. I knew it wasn't legal,

But yet for some strange reason the mechanics and CFI's at the FBO had a million ways to explain and get around it.

The "Zero Fuel" Myth - You know, Fuel Gauges only Need to be Accurate when Empty

You don't really need to know what happened after this true Accident Narrative - It is evident from the beginning.

Picture Draw Jerel Draw,  jereldye.com

Prior to the incident, I received an instructional ride and completed my C-172 checkout. I then flew with a passenger and solo, three flights, for a total of 5.3 hours in the bird.

In all three of those flights.

• I observed erroneous fuel quantity indications,
• Intermittent cycling of the fuel gauges to zero.
• LH Fuel Low Level Warning light coming on intermittently. 

An [instructor] told me this condition was well  known, typical for this aircraft and not uncommon for general aviation aircraft.

I discussed the erroneous fuel quantity indications with the Chief Pilot, and asked
him if I should write them up. 

He said no, that the indications were within the spec, which requires only that they
read accurately when empty.

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The statement that fuel gauges only read accurately when empty is repeated so many times in the aviation dialog.

 You would almost have to believe it is true.

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Actually far from it.

• It is a comment you hear repeated by many pilots, the magazines & AOPA / FAA Safety Briefs.  

• It is not uncommon to have bad fuel gauges in aviation, it is frighteningly almost the rule.  

What is true: 

• Fuel gauges are "Required" aircraft instruments for powered aircraft.

• They are required to be functional by design and in operation on the aircraft   -  Specifically:

• Read fuel level from FULL to EMPTY.  
• EMPTY needs to be calibrated at "Zero Usable Fuel"
• The Zero Usable Fuel is the fuel level,  where in the worst condition - fuel cannot be drawn from the tank.

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Designing, Maintaining or Flying an aircraft with bad or in-operative fuel gauges is illegal.  

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Why is it surprising that so many GA pilots run out of fuel.

I think the answer is obvious.

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Let's Elevate the Discussion about Fuel Exhaustion so it won't Bring us Down

I have been engaging with an active Aircraft Owners Pilot group about Fuel Exhaustion and it's potential causes and solutions.  As Fuel Exhaustion and Starvation span the  GA spectrum I thought I might share the dialogue.

Flying Magazine - May 2013

Flying Magazine

Well we have been waiting for this -

Recognition in the press or an editorial resulting from a flight utilizing our fuel level sending technology.

When reading about all the very significant changes made for the new 2013 G5 Cirrus.  You will see the mention of accurate fuel level - not once but three times.

In this aircraft review there is an discussion about the fuel imbalance messages being determined by fuel level.

Not the Fuel Totalizer - the Fuel Level System 

If you pay close attention -  the differential they are talking about is an accurate reading of a level of fuel at 8,  10 gallons between the two wing tanks and then at 12 gallons. 

Yes -- our senders give levels of accuracy in the 46 gallon tank of less than  two gallons.

Again in the side bar - a mention of not just accurate - but highly accurate fuel level.

I

Imagine an editorial in General Aviation magazine - praising the quality of the fuel indication.

Not Fuel Totalizer -
The Fuel gauges

And finally in the specification banner another mention of the electronic fuel level sending units.

While we strive every day to change fuel level sending in aviation with better technology, quality assembly 

and attention to detail 

We are very proud that our efforts are being recognized 

Cirrus Aircraft Fuel Level Retrofit - Video

Cirrus Aircraft Fuel Level Retrofit 

We set out to change fuel level in Aviation.  We wanted to demonstrate that accurate and reliable information on fuel quantity could be accomplished in single engine and other aircraft.

The concept has literally taken off.  

We have proven they we can measure fuel in a highly dynamic environment and we can do so accurately.   


Click Here for Cirrus Inflight Video 

Measuring Fuel ... How Do you Measure Up?

I have been trying to track down this exact "Pilot Folklore" regarding fuel level in aircraft.
  
Specifically the widespread pilot belief that the FAA doesn't require for you to have working fuel gauges in your aircraft.

The gauges only need to tell you when you're empty.

Sure enough in a FAA Safety Bulletin in April 2002
The FAA said just that - the exact words as follows:

 As you can see, the regulations only require that the aircraft fuel gauge read “zero” during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply determined under 14 CFR §23.959(a).  Therefore, the gauge cannot be depended upon for checking the fuel quantity in a tank. This is especially true of the smaller, less sophisticated general aviation aircraft. Visual or physical checking or both are the only safe means of determining the actual quantity of fuel onboard such aircraft. How do you measure fuel? Do you measure up?  H. Dean Chamberlain 

In fact,  as recently as February 2013, the FAA allowed this to be reprinted in a blog site... unbelievable.   Supporting a culture where it is acceptable for "Fuel Exhaustion" to be one of the TOP 5 GA Incidents, and according to the AOPA Nall Report the second highest cause of pilot death.

In most cases pilots will blame  pilot behavior and preflight.  All pilots will rally to the aviator cause, and like this FAA article, seek to change the an obviously errant pilot procedure.   .... Education is the tool to address this serious safety issue .  Despite the efforts, the number of fuel exhaustion incidents still remain high.
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So back to the fuel gauge ....  I have been through over 150 certification meetings in my life - 

But I have not yet brought in a new aircraft or new aircraft modification and told the Administrator that; 

I removed the fuel gauge and  replaced it with an idiot light letting the pilot know -

"That at this very moment you ran out of fuel"  

or propose an aural announcement like:

 "WARNING YOUR ENGINE WILL NOW STOP... PLEASE LOOK FOR A SAFE LANDING & HAVE A NICE DAY"

But according to the FAA author above - that is exactly what the administrator is looking for in an aircraft design  ....

...   REALLY,  What pilot or aviation professional believes this?


 So what do the FAR's (Federal Airworthiness Requirements) really say:

Title  14 Code of Federal Regulations (CFR) §23.1337(b), Powerplant instruments installation.

  It reads:

(b) Fuel quantity indication. There must be a means to indicate to the flightcrew members the quantity of usable fuel in each tank during flight. An indicator calibrated in appropriate units and clearly marked to indicate those units must be used.

It says you have to have a fuel gauge and it needs to show you the amount of fuel in your tank in flight.  It says that in fairly clear language. 

In  addition:  

(1) Each fuel quantity indicator must be calibrated to read “zero” during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply determined under 14 CFR §23.959(a);

It says that the fuel gauge must have the capability to be be calibrated to read zero usable fuel.  This feature is an added part (In addition) to the requirement that it must  let you know how much fuel you had in total,  when the aircraft is in flight.

Does anyone believe that the FAA would have you put a fuel gauge in an aircraft and 
let that gauge

• Indicate any value fuel level other than zero.
• When you were at zero usable fuel it will read "ZERO"

According to this skewed interpretation of the regulation.

A binary gauge meets this folklore requirement   ... 

•  "SOME FUEL"

to be followed by a calibrated  

• "NO FUEL" 

Well the FAA actually expects something dramatically MORE Accurate 

in FAA TSO C55a -

- No more than 3% of full scale tank volume in the worst case -

Minimum Performance Standard for Fuel and Oil Quantity Indicating System Components, 

When you get in your aircraft and you look at your fuel gauges.

• Do they meet the real and intended FAA standard. 

or 

• Do they just give you folklore.