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

That's a pretty bold statement.  

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

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

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

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

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

A Functional Aircraft Fuel Gauge has the following two Characteristics

• In level flight the indicated amount of fuel shown on the gauge should be within 3% of actual fuel volume in the tank.  

• When the fuel is at a low level demonstrated to the FAA to be the minimum fuel that can be drawn from the aircraft in all normal maneuvering flight conditions this demonstrated fuel quantity will be the "Zero" or "Empty" fuel level value.

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

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

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

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

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

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

What if We Legislated Accurate Aircraft Fuel Level

Yes Virginia, Bad Fuel Level Indication Can Lead to Aircraft Fuel Starvation.

If you look at the small aircraft fuel starvation/exhaustion statistics you might make an assumption that aircraft might have poor fuel quantity indication systems and you might be exactly right.  What is more astounding is that the FAA will agree with you and put it in writing.   Three to four aircraft a week find a way of running out of fuel in North America.

But if you ask a pilot - they will probably equivocate and  shift the responsibility for these fuel starvation events elsewhere. 

So let's look at some of the basics:

Every transportation system, save small piston and turboprop aircraft in North America,  when you evaluate fuel starvation from a functional hazard assessment, indicate that a failure or inaccuracy of the fuel indication is a causal factor in fuel starvation.  

Lets look at the closest brethren to small aircraft - our commercial aircraft cousins.

 

In large commercial aIrcraft fuel quantity indication has been determined to be a leading factor in fuel starvation - The example of the Gimli Glider a Air Canada Boeing 767 that suffered fuel exhaustion and glided to a landing was due to erroneous fuel loading calculations and fuel-gauge malfunctions.

The aircraft's fuel gauges were inoperative because of an electronic fault which was indicated on the instrument panel and airplane logs (the pilots believed the flight was legal with this malfunction)

In an Aviation Week Article in Nov 2011 

EASA Proposal Targets Fuel Starvation Risks

Lessons learned from 65 transport aircraft fuel starvation incidents and accidents in the past four decades have prompted the European Aviation Safety Agency (EASA) to propose certification rule modifications designed to mitigate the occurrence of similar incidents. 

The notice of proposed rulemaking (NPA-2011-13) issued this summer would modify EASA's certification specifications for large aeroplanes (CS-25) by requiring the installation of fuel identification systems, replacing the currently required fuel quantity indicators for each fuel tank. The new systems would have to permanently display to the flight crew the total quantity of usable fuel on board as well as in each fuel tank. provide low-level fuel warnings for each tank, and warn the crew of an airplane configuration that, if left uncorrected, would starve one or more engines of fuel.

In this case EASA would like to improve aviation safety by putting in a better fuel quantity indication system in Commercial aircraft to address the Fuel Starvation hazard.

Not so in General Aviation, Let's look at how AOPA handles this same concept.

• Know how much fuel you have onboard. 

• Think of Fuel not in Gallons but in Hours and Minutes.
• Use a calibrated Dipstick and your Fuel Computer (Trip Computer)
• Depart with Full Tanks

• Know your fuel system 
• Know what kind of fuel is in your tank
• Update your status during flight
• Land with adequate reserve

In this helpful Fuel Awareness White Paper somewhere at the end

• Finally "some sort of Fuel indication is provided for the pilot" 

So nowhere in this paper does the AOPA tie the fuel you have onboard your small aircraft to your fuel quantity instrumentation in the aircraft.  Instrumentation that is designed to let you know your remaining fuel quantity, nowhere. 

It is a fact that a working fuel indication system should help you determine how much fuel you have all the way through your flight. 

Why do we tolerate this in General Aviation Aircraft.  

By FAA regulation you are supposed to have Fuel gauge for each and every aircraft tank. When you take delivery of a new aircraft you should expect the following from your fuel indication:  Part 23

• This gauge is to read from Full to Empty 

• Where Empty is the least fuel you can safely use.

• This gauge is to be marked with Numbers and what these Numbers represent i.e. Gallons.

There is no other performance standard for this gauge and even for large commercial aircraft the fuel indication regulation reads exactly the same.

In commercial aircraft the fuel indication system typically meets a TSO Standard which is a numerical quality standard for indication.  Maintenance is required to show that this system is maintaining that standard. 

Here is where it get's lost in the General Aviation world.  There is no quantitative  (numerical)  performance standard in the regulation.   The fuel quantity system does not typically meet a numerical performance TSO standard.  In fact it has been stated, that it only needs to be accurate when you are Empty.   This statement is not folklore its printed FAA policy and guidance. 

The  FAA Position - We don't really have a usable standard, it's up to you. 

The follow on regulations for the pilot and mechanic are equally vague and fuzzy and they are as follows: 

Pilots need to have a working fuel gauge indicating the quantity of fuel in each tank.  Part 91

Mechanics need to insure the following under the aircraft's mandatory yearly maintenance: Part 43

• Check for poor condition

• Check that the gauge is properly secured to the aircraft

• Check to insure the markings are clear 

• Check (where practical) for improper operation 

So we have a  touchy / feely standard for what constitutes a working fuel gauge in general aviation.  

If we peer into the maintenance manuals - this aviation requirement is equally spongy and strangely consistent for every small aircraft manufactured.   

Most aircraft manufacturers have issued Service Bulletins outlining a calibration procedure that could be accomplished to insure the system is somewhat accurate, but is not required.

There is no quantitative standard for for small aircraft fuel gauge accuracy and no quantitative standard in the field to determine if the fuel gauge is providing useful information to the pilot.

 Actually accuracy is left up to the personal discretion of the pilot and their mechanic to a personal definition of "working" and "improper operation".   This is obviously a purely qualitative evaluation.  

Remember:

 If you can't measure it 

you can't manage it.

Let's look at an example of  how small aircraft fuel indication should be handled:

The Australian Civil Aviation Authority came upon this lack of a consistent standard and decided to do something about it.   The Australian fuel quantity performance standard has to be met 4 year intervals.   This testing is mandated by law and very similar in result to an FAA or EASA AD.  You must comply, but it deals with forcing proper maintenance and not addressing a manufactured design defect.

This mandatory repetitive compliance testing has a clear qualitative standard that is traceable back to the FAA requirement and the underlying Society of Automotive Engineering requirements for fuel indication in aircraft.  

The standard is flexible enough to account for aircraft that have rudimentary sight gauge indication systems.   

Even more impressive is that this standard is combined with an element of best practice to insure an aircraft has accurate fuel level indication for the pilot to use.

Basically these standards are :

• That the Fuel Gauge progress smoothly and continuously to empty as fuel is drained.

• The Fuel Gauge reads Empty with the zero usable fuel level in the tank.

• If the Fuel Gauge is marked at major graduations for fuel quantity (Part 23 Aircraft) that the gauge indicate within a few percentage points of that marked value.

• If the Fuel Gauge is marked in 1/4 tank increments (E,1/4.1/2,3/4, F) that a placard be placed along side the instrument to list the numerical volume associated with that mark. 

Simple and straight forward, Why don't we give it a try. 

Fuel Exhaustion - Are We Set Up To Fail

Our expectations are so low for aircraft fuel level gauging systems, They are hardly ever relied on.

In fact when we educate new pilots this is typically what is said.

• The first one is taken from the AIM

FUEL REMAINING—A phrase used by either pilots or controllers when relating to the fuel remaining on board until actual fuel exhaustion. When transmitting such information in response to either a controller question or pilot initiated cautionary advisory to air traffic control, pilots will state the APPROXIMATE NUMBER OF MINUTES the flight can continue with the fuel remaining.

All reserve fuel SHOULD BE INCLUDED in the time stated, as should an allowance for established fuel gauge system error.

• The second one from the Irish Aviation Authority

Aircraft fuel gauges can be notoriously inaccurate so it more reliable to “dip” the tanks to establish how much fuel is onboard. However, make sure that your dipstick is calibrated to suit your aircraft type, the aircraft is parked on level ground and the fuel level has been allowed to stabilise before you dip.

• The final one from AOPA  Flight Training Magazine

Use the clock - not the fuel quantity indicators on the panel - as your fuel gauge. In other words, plan and track your fuel consumption based on endurance, not range. Unlike range, endurance is not at the mercy of winds. Besides, those fuel gauge indicators probably won't be very accurate except when they read empty - a setting you should never see. 

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

In fact the pilot mantra given to prevent Fuel Starvation and Exhaustion is  "PREFLIGHT, PREFLIGHT, PREFLIGHT  

So what do we normally look for in a PREFLIGHT inspection - tires, brakes, oil level, security of the flight controls, condition of the prop, security of the fuel caps.   Basically all the stuff you can't check in flight.

The implication here is - you have only one chance per flight to check your fuel level - & that one chance is at your PREFLIGHT inspection.  - If you avoid that critical step, you are flying on borrowed time buddy.

Here is the rub  - you are supposed to be able to monitor your fuel level throughout your time in the air.

Another Pilot Mantra could just as easily be be "INFLIGHT, INFLIGHT, INFLIGHT.  That INFLIGHT scenario would be the pilot comparing anticipated fuel level, to actual indicated fuel level.  This would be the pilot vigilance stuff, you know the cross checks of fuel remaining from the calculations to what is onboard.  

Fuel Gauges are required instruments and found on all powered aircraft - So yes the FAA actually expected them to work.  ---  I bet you are surprised.

You are, by design, supposed to be able to see how much fuel you have at any time while you are in the air.   It is the law, it really is, and it really is a good idea.

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

In 1974 (yes that long ago) the NTSB initiated a study on Fuel Starvation,  in this study,  they found that there were some aircraft that rarely had a fuel starvation event,  and they also found some aircraft that were prone to the issue - Most aircraft as you might guess were average in this regard.

SO what this study pointed out, it didn't really come right out and say it,  but it was pretty clear that fuel exhaustion wasn't just a pilot thing  - 

If it were, pilots being human - some good, some bad & most of them average would equally suffer fuel starvation in any aircraft.  It would not matter which aircraft you flew.

An average pilot in an average aircraft might have a fuel starvation event - but not really that likely.

An average pilot might never experience a fuel starvation in "X" model aircraft, but that same pilot might be assured of a high probability of fuel starvation if he flew "Y" model aircraft 

As General Aviation is slow to change - some of those aircraft are still in production.  In fact some of those aircraft in the study are still flying.

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

So what did the Aircraft Manufacturers recommend in the 1974 Report:

• Two manufacturers recommended a separate Low Fuel warning system. 

• One manufacturer recommended that a more accurate and reliable fuel level system be developed. 

• One manufacturer believed that a "one tank system" would be beneficial.

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

So what did the NTSB recommend in the 1974 Report:

• Specification for a low fuel level warning that would operate independently of the existing fuel gauging system.

• Specification for a more accurate type fuel quantity gauging system. 

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

That was 40 years ago - so 

Where Are We Now! 

I am guessing from the picture,  that we are still on the road to find a solution.

PA28 Lands on a Parkway

Instructor-Pilot Lands Stalled Single Engine Plane Safely on Palm Coast Parkway

FLAGLERLIVE | MARCH 13, 2013

The Piper after it had been pushed off Palm Coast Parkway, sitting in the setting sun as onlookers took in the scene. Click on the image for larger view. (© FlaglerLive)

Phoenix East flight school’s Raul d’Souza is a hero: the young instructor was piloting a plane late this afternoon, practicing emergency landings with a student, when the plane ran into engine troubles–and forced D’Souza, 34, to execute an emergency landing in the heart of Palm Coast. He did so nearly flawlessly.

Raul d’Souza, a new Sully Sullenberger, immediately after the landing. Click on the image for larger view. (© FlaglerLive)

With him was Joo Lee, 33, who looked distinctly shaken from the experience. They both smoked, paced, sat, and smoked again soon after the landing. They’re both based at Phoenix East Aviation, on Pearl Harbor Drive in Daytona Beach. D’Souza, who’s been at the flight school since at least 2004, maintains a YouTube page of favorites that includes several video clips from the flight school.

An SUV–or at least a large white car–had to do an evasive maneuver as the eastbound plane negotiated the two rather narrow lanes of Palm Coast Parkway west, and a huge semi, carrying cars, was also on the road; the plane faintly clipped the truck, but managed to land on the road. The truck had been parked on the shoulder, having just picked up a Mercedes from Parkway Self Storage. The plane clipped its left-front guide-pole with the marker light on its left wing, which shattered, leaving tiny and still-visible fragments on the fender above the truck’s left-front-tire. The plane also clipped the air cleaner, which was dented.

The single-engine Piper, built in 1968, landed safely at 6:45 p.m. on Palm Coast Parkway, just west of Belle Terre. The plane sat on the road for less than 20 minutes before authorities and one of the two occupants of the plane pushed it off the road and parked it at the entrance of Parkway Self Storage. The wesbound lanes of Palm Coast Parkway were shut down only briefly.

The plane belongs to Daytona Aircraft Leasing Inc., based at the same address as the flight school. D’Souza had reported engine trouble to the Daytona airport’s tower just after 6:30 p.m. Authorities in Flagler got the call of a plane in distress at 6:37 p.m., when dispatch announced an airplane emergency, describing a plane approaching Palm Coast Parkway from the west, toward the east, and possibly looking to land there. Shortly afterward, the landing took place.

The pilot and his passenger declined to be interviewed, referring questions to their safety supervisor, who was on his way from Daytona Beach. The Florida Highway Patrol was investigating the incident, which it categorized as a crash the moment the plane struck the truck.

Hayden Gordon, whose truck the plane clipped on its landing approach. Click on the image for larger view. (© FlaglerLive)

Hayden Gordon, 52, has owned the truck since 1999, and said he’d never had any road incident resembling his experience Wednesday afternoon. He’s based in Port St. Lucie. He was on his way to New York City, after starting to pick up cars in Miami. He had three on the truck. “I didn’t really see it,” Gordon said of the plane’s approach. “I was parked here, I’d just put the car up, and I was right here, getting ready to chain it” he said, describing his position to the right of the truck, with the truck blocking his view of the parkway. “Then I hear the sound, I hear it go boom. So when I spin around I saw the plane. There was a car coming. The car went right under. The car went right under it, yeah?” It was a white car. “And I saw the plane hit the ground and run out.”

Gordon ran down to see the pilots, who had immediately bailed from the plane and run to the south shoulder of the road, on the grass. “It kind of scared me a bit, you know,” Gordon continued, after he’d realized what had unfolded, but “they were fine,” he said of the plane’s occupants. “The guy said his engine went out, he tried to start it but it wouldn’t start.”

No NTSB Action 

Fuel Exhaustion - Another PA28 Finds a Road

Plane makes emergency landing on Watterson

Posted: Oct 07, 2010 8:22 PM PDTUpdated: Oct 08, 2010 8:08 AM PDT

 

 

 

By Marisela Burgos - bio | email
Posted by Charles Gazaway - email 

LOUISVILLE, KY (WAVE) - Early Friday morning, emergency crews remained on the scene of a small plane that made an emergency landing on the Watterson Expressway near Taylorsville Road.

The plane, a Piper PA-28, landed in the westbound lanes of the Watterson just west of the Taylorsville Road ramp shortly after 11 p.m. Thursday. Four people were reported to be onboard, but no injuries were reported.

The aircraft came to a stop on the grassy shoulder of the interstate off the driving lane. Traffic on westbound Watterson was flowing using the outside lanes.

According the FAA website, the registered owner of the plane is Benjamin Price of Fisherville, KY. It is not known if Price was onboard the aircraft at the time of the emergency landing.

Kathleen Bergan, communications manager of the FAA Southern region, said initial reports indicate Bowman Field was the plane's intended destination. Bergan said the FAA is investigating and the National Transportation Safety Board has notified of the crash.

NTSB Report 

The pilot stated that he estimated the airplane's fuel supply during his preflight planning by calculating the fuel consumed during the two previous flights. The pilot departed for his destination and planned to land with 45 minutes of fuel reserve. During the flight, the airplane encountered wind stronger than forecast and the airplane consumed more fuel than he had estimated. On descent for landing, the airplane experienced a total loss of engine power and the pilot attempted to glide to the runway. As the airplane's airspeed and altitude decreased, the pilot opted to land on the freeway below. The airplane touched down in the middle lanes, skidded along the pavement, and came to rest in a ditch. During the accident sequence the airplane incurred damage to the right wing and horizontal stabilizer. Post-accident examination of the airplane by a Federal Aviation Administration inspector revealed that both tanks were absent of fuel and that there was no evidence of a preimpact mechanical anomaly.

Aircraft Fuel Totalizers - A Self Fuel Filling Prophesy

One of the more difficult things to measure is liquid fuel on a moving vehicle.  

This is true of aircraft, boats and heavy equipment.  

By it's very nature, liquid fuel refuses to stay still.

So to address these issues with fuel level sending technology,  we have turned to fuel flow instruments and fuel totalizers.  

These instruments measure the fuel flow to the engine and remove that fuel volume from an owner/operator entered starting fuel value.  They can give you a  knots per gallon indication. 

This can be done by several methods - we can count injection pulses and duration or we can get a sensor to measure fuel on the way to the engine,  and in injected engines fuel on the way back to the tank.   There are several sensor types that will perform this function

Some of our cars do the same thing - only they reset when we fill the tank or in other words when the fuel level reaches full.

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

Many owners will swear by the fuel totalizer and it's uncanny accuracy.

I filled the tank and then burned 35 gallons of fuel.   When I refilled - I put 35 gallons back into the tank.  

Sounds good - and a justification for the expense of having this equipment installed - However an aircraft tank filled in the same manner and in the same location - the fuel totalizer is a self - fuel filling device.

• I will never run out of fuel with this equipment installed.

• I don't need fuel gauges 

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

So what does the FAA say about fuel totalizers 

Digital fuel flow computer systems have a fuel flow transducer that directly measures the fuel being fed to the engine.

The fuel flow transducer may be a small paddle wheel, an impeller, or spring-loaded movable vanes. 

Digital displays with a fuel computer also allow these instruments to display total fuel consumed, total fuel remaining, and time remaining at the present fuel
flow rate for fuel management. Overall accuracy for fuel remaining and time
remaining readings depends on the transducer processing unit and display.

The largest possible error is the initial fuel supply, which is entered by the pilot at the start of each flight. Errors in the initial fuel supply may be caused
by an uneven ramp, unusual loading, volume changes of the fuel because of
temperature variations, malfunctions in the fuel system such as leaks,
siphoning actions, collapsed bladders, and other factors.

So, total fuel remaining should be verified with the fuel quantity indicator. According to § 23.1337(b)(1), fuel quantity indicators are required to be calibrated to read "zero" during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply. Therefore, fuel quantity indicators should be used as the primary fuel-remaining instruments.

Fuel quantity indicators that are inaccurate should be periodically calibrated, repaired, or replaced, as necessary, to ensure reliable readings.  

Taken from  FAA AC 23-17C

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

The only issue with the FAA message above is that it was written for aircraft engineers, certifying new aircraft or modifications -  

It really should be shared with the pilot and aviation maintenance community.   

Why not?

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

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.

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.

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

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.

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

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.

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

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

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

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

I think the answer is obvious.

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

Fuel Starvation in a Modern Technologically Advanced Aircraft.

It is common to believe that technological advances can mitigate the dangers inherent in operating vehicles.  The automobile airbag is one of the best examples - it was first hard to convince us all we needed one - now every new car has 10's of them.  It was a safety idea that worked.   

One of the most difficult Safety Issues in Aviation - Especially light aircraft is Fuel Exhaustion. 

And we have a strong belief that modern aircraft with modern tools can mitigate this problem.  

There is a definite trust in the pilot community that fuel totalizers (fuel range calculators) mitigate the danger inherent in running out of fuel in a small aircraft.   This is the technological advance intended to help alleviate fuel starvation events for small aircraft.   For those not in the aviation field - you are guessing correctly that running out of fuel in a small aircraft is not a good thing. 

So lets look at a recent Fuel Starvation event in a modern Cirrus SR20.  

The National Transportation Safety Board provides a Probable Cause for this accident that occurred in Parker AZ - 

I included it below -

Before the first flight of the day, the pilot visually checked the airplane’s fuel quantity through the fuel tank filler necks, observing what he believed to be full tanks.  He subsequently checked the fuel gauges, which indicated that both wing tanks were less than half full.  Surmising that the gauges were faulty, the pilot departed on a short flight to a local airport to pick up a passenger.  After picking up the passenger, they departed for a cross-country flight.

So this subject pilot observed full tanks (he actually looked at the fuel in the tank),  and then checked to see what his gauges read.  Then this Cirrus pilot with an "obvious" discrepancy between his observed fuel and his fuel gauge reading,  proceeded on his planned cross-country trip.   

It is my conjecture that he entered full fuel on his fuel totalizer.  The totalizer is a system that uses fuel flow and a pilot entered quantity to provide a range of travel.  Systems like this are common in boating and you see them in your car as a fuel range.   So this pilots "trusted" fuel reporting system supported his  observation.   

This pilot then departed with in his words "faulty gauges"  - and in violation of Federal Law Title 14,  Part 91 -  included below:

§91.7   Civil aircraft airworthiness.
(a) No person may operate a civil aircraft unless it is in an airworthy condition.
(b) The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight.  The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.

So this pilot operated his aircraft with with an un-airworthy mechanical condition based on his observation of fuel level.  

In fact if you ask a pilot friend if they are currently flying an aircraft with a faulty fuel gauge you will get a nearly unanimous answer that yes in fact they are.

Typically they will soften the blow and let you know, 

• That they have never run out of fuel.
• They can look in their fuel tanks on the ground to see how much fuel they have. 
• They will tell you that a stopwatch will let them know when to land.
• And aircraft typically are operated at one speed - so fuel consumption per hour is fixed.  I have 50 gallons of fuel - we burn 10 gallons an hour - so we can go 5 hours maximum - and today we will only fly 3 hours.
• Some will even tell you that they have a Totalizer - and it's far more accurate than any fuel gauge 

As you can correctly guess - this law, the one that requires working fuel gauges in aircraft, is not enforced.  Nobody is getting busted, and frankly nobody is worried about it either.    

But this pilot didn't break the law -  the fuel gauges were right and his aircraft was in the legal words of the law - airworthy -    The only thing this pilot did was err in his observation of the fuel level in the tank.   Human error it happens all the time  

So a little more conjecture based on what we know of the Cirrus SR20 aircraft   -  This pilot in believing his gauges to be wrong,  he then ignored the the multiple low fuel level messages that occurred during flight.   You could think of these aircraft warnings as a low fuel warning lights - that first come up amber and then change to red as the fuel is being depleted out of the tank.

These low fuel messages were warning him of an impending fuel emergency,  most likely where he could have taken action and landed safely.   But this pilot appeared to have trusted his  "Fuel Range Map -  and his fuel range on that map was based on his erroneous fuel level observation and his range map was counting down from a full tank of fuel.   He might even have carried a stopwatch to let him know at what time he would have run out of fuel.

This is the cultural issue in aviation  - 

• Pilots find it acceptable,  actually common to fly with a faulty fuel gauge.
• Pilots expect that the fuel gauge is misleading and proceed to fly anyway.
• Pilots were trained to ignore their fuel gauge   
• Pilots continue to run out of fuel in their aircraft 

If this pilot trusted his fuel gauge - and then used it as a cross check to his fuel level observation - he would have exited the aircraft on the ground  and re open the fuel tank and reviewed his observation.   In fact as he made a short hop to pick up a passenger -  he could have rechecked the fuel level twice.   If I we use this aircraft's  Pilot Handbook Checklist - a visual tool that pilots use to insure everything is working as it should,  prior to flying - he would have looked at his fuel gauges a minimum of 10 times,  and he then ignored his fuel gauges each and every time.

Fuel Starvation - or running out of fuel is a leading cause of aircraft accident, injury and death.

So what are the FAA, NTSB and the Pilot Organizations doing about this -  

Well, not surprisingly

  They too want to ignore the fuel gauge.

Again nearly all pilots were trained to do so.

In the most recent video & safety bulletin put out by AOPA and a they have placed a lot of effort to train this pilot to visually observe the fuel in his tank. 
Pilots, due to the cultural influence can't grasp the idea that a working fuel gauge could possibly mitigate fuel starvation.
  
It never occurs to them.

And it is really is a head in the sand approach,  As these pilots are all cross checking each other, and sharing their own experience.   

Just like the airbag, we were resistant to add safety, as it added cost, and we doubted the benefit - but the value of the lives it as saved has made it more than worth it.  

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

Let's change the culture in aviation and quit making excuses and ignoring equipment that doesn't perform to the aviation standard .