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. 

PA28 Lands on a Road

A 1968 Piper PA-28R-180 Cherokee single-engine aircraft with four persons on board made an emergency landing on southbound Interstate I-15 between Escondido, Calif., and El Norte Parkway on Sunday evening, July 22, 2012 at 11:25 p.m. PDT according to reports published on Monday, July 23 by KGTV 10News San Diego, the Los Angeles Times, the Kathryn's Report, the North County Times, and other media.

The pilot, 48-year-old Ken Gheysar of Orange, Calif., was en route from Mammoth Yosemite Airport (MMH) to McClellan-Palomar Airport (CLD) in Carlsbad, Calif., but ran out of fuel and decided to put down on the freeway.

According to CHP officer Jim Bettencourt, "Since traffic was light at that hour he was able to land safely and make it to the right shoulder of the freeway just north of El Norte Road."

The plane landed safely and was undamaged, until the tip of the left wing was clipped by 74-year-old Milton Loy of Poway, who was driving a 1995 Dodge Dakota, causing minor damage to the aircraft and pickup truck.

Joel Siegfried

Airport Examiner

NO NTSB Action

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.

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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.

The Aviation "Zero Fuel" Parody

We thought we would take the commonly held belief and mess with it a bit.

"The aircraft Fuel gauge only has to read Zero when the tank is empty"

It was interesting to take this assertion and take it to impossibly illogical conclusion


http://youtu.be/fnREv_bz9Qc

Don’t Blame your Fuel Gauge

"According to the Joseph T. Nall report (produced by AOPA’s Air Safety Institute), 89 accidents occurred in 2010 as a result of fuel exhaustion; 11 of them fatal. And despite a decline in fuel management accidents through 2008, more recently those numbers have been reversing, accounting for eight percent of all accidents in 2010.
According to the Nall report, inadequate flight planning — failure to determine the amount of fuel required for the flight or the amount actually on board, or to verify the rate of fuel consumption en route — accounted for the largest share (48 percent)."

This was reported below in the FAA Safety Team Briefing in October 2013 and is indented in italics:

FAASafety

Briefing - Fuel Monitoring 

October 2013

The General Aviation Joint Steering Committee

Safety Enhancement Topic of the Month

Don’t Be “Fuel-ish”

While fuel exhaustion continues to be a a top ten issue for General Aviation safety - It gets very little insight or a real root cause analysis to the factors involved.  To most in the aviation field this is a simple pilot problem with a very simple answer, But there is a hidden truth lying in the commonly held belief below:  

"One of the more head-scratching aspects of fuel management accidents is simply how easy they are to prevent, as well as recognize well before they happen.Blaming a bad fuel gauge doesn’t cut it. To help prevent getting into this situation, here are some tips:"

Note:  A fuel gauge is required equipment on all powered GA aircraft and it is supposed to be accurate throughout the range from empty to the zero fuel level.  

The FAA Safety Team implies in the paragraph above that you could be flying your aircraft with a bad fuel gauge - I hope this isn't so.

§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.

§23.1305   Powerplant instruments.
The following are required powerplant instruments:
(a) For all airplanes. (1) A fuel quantity indicator for each fuel tank, installed in accordance with §23.1337(b).

§23.1301 (Systems and Equipment) Function and installation.
Each item of installed equipment must—(a) Be of a kind and design appropriate to its intended function.(b) Be labeled as to its identification,function, or operating limitations, orany applicable combination of these factors;(c) Be installed according to limitations specified for that equipment; and (d) Function properly when installed.

§23.1337   Powerplant instruments installation.
(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. 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 §23.959(a)

And this is where the hidden truth lies,  and this is where I believe the  FAA Safety Team author missed the point - It is a subtle but significant difference and it should read as follows:

Flying an aircraft with a bad fuel gauge doesn't cut it 

If we review  -  I believe the accident chain starts at this point.

• After visually checking the fuel in the aircraft,  the pilot then got into the aircraft   put power onto the aircraft and observed that the fuel gauges did not report accurately how much fuel was in the tank.  

Or 

• The pilot observed on filling the aircraft that the gauges indicated the aircraft had more or less fuel than that required to fill to tabs as an example.

STOP RIGHT THERE - Take your aircraft to the nearest service center and have your required aircraft equipment repaired or replaced to make your aircraft airworthy.  

Don't fly an aircraft with bad fuel gauges - it is that simple.

If you are flying an aircraft with bad fuel gauges - you should have a ferry permit.     

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When you look at it from this perspective - yes the solution to fuel exhaustion may be just as easy as the brief author suggests.  

Simply mandate that required fuel level reporting equipment function properly when installed on the aircraft.  

I understand fuel level reporting is not good in GA - That they don't work is the universal complaint.  

If that is true, then this problem lies with the FAA Administrator -

1.) Did the FAA Administrator allow an Aircraft Type Certificate to be issued that ignored fuel level reporting requirements of FAR 23.1301, FAR 23.1305 and FAR 23.1337.

2.) Does the FAA enforce the requirement that this equipment is to function     throughout the life of the aircraft as designed above.

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Why have we turned a blind eye to fuel level equipment & why are fuel reporting systems treated in a different manner than any other required equipment on the aircraft. 

Because if we re-write the FAA Safety Brief and replace fuel level with another piece of required equipment ..... Frankly, it just sounds silly.   

"One of the more head-scratching aspects of airspeed management accidents is simply how easy they are to prevent, as well as recognize well before they happen.Blaming a bad airspeed indicator doesn’t cut it. To help prevent getting into this situation, here are some tips:"

Required equipment is required for a reason - let's make it that way.