Tilting @ Propellers

Illus. Chris Demerest http://chrisdemarest.net 

Today I took a call,  the pilot on the line was enthused, he really wanted to get our new technology fuel senders on his aircraft.  

Further he engaged us in a dialogue wanting to let us know how significant this product was to aviation, and to his passion, you know the type,  a typical Mooney pilot.

He told me about the AOPA statistics on fuel mismanagement and starvation, and that it wasn't good press for general aviation or general aviation safety  to have a fuel starved aircraft parked along  a busy highway.

He was adamant to tell us about the significance of redundant and confirming cockpit information.  Being able to cross-check the two independent fuel quantity indications in his cockpit, he felt, would virtually eliminate fuel starvation in general aviation aircraft.

He talked about the level of quality he saw in fuel senders used in aviation, and that he just hoped he wouldn't have to overhaul his original set for the umpteenth time, and then have them fail hours later in flight, as they had on the past two occasions.

He related to me that as a multi type rated and experienced pilot he had never flown behind a good aviation fuel gauge in his entire life.

I didn't say a word  I sat back and listened to the sentiment that put us on the path to start a company around this product and idea.

The idea that we will build a good fuel level sensor, a quality fuel level sensor,  around robust patented technology using aerospace materials and standards.   We will prove our commitment by qualifying this fuel sensor to the most ridgid FAA standards for manufacturing and design.

My dream is that pilots will get this and install or demand this technology on their aircraft.  If that happens, we will make a lasting contribution to the aviation industry.

So many times in this aviation business,  you feel like you are setting your train along the wrong track,  why are you building a company in aviation,  when successful people all around you question the market size, vitality and rational.   You question your own sanity on a daily basis.

I guess we do this,  because our passion makes us tilt toward that propeller.  some days it's nice to know we aren't the only ones.

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.

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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 

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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

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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?

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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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Selecting your Fate - Choosing the Proper Tank.

We read so many aviation fuel starvation accident reports and the published responses from AOPA and others  

"On March 12, 2005, a 24,611-hour ATP made a forced landing in an open field after a total loss of engine power while on a visual approach to Runway 13 at Lancaster Airport in Lancaster, Texas. He and the one passenger were not injured.
The pilot did not visually check the fuel tanks prior to takeoff and could not recall "what the fuel gauges indicated"  during the flight.
He thought both auxiliary fuel tanks were full, and both main fuel tanks were almost full.  While descending for the approach, the pilot moved the fuel selector valve from the left main tank to the right main tank" 

Here is where we believe accurate or at least functional fuel level comes into play - The pilot did not look at his gauges - if he had,  and they were operating as designed - He probably would not have switched to an empty fuel tank.

Very shortly after, the engine quit. The pilot unsuccessfully attempted to restart the engine by switching the fuel selector valve back to the left tank and cycling the throttle.  

It is interesting that the neither the FAA nor NTSB tested this aircraft's fuel gauges for operation.  They only tested the engine. 

   We have all become complacent that aircraft fuel gauges can offer little or no assistance to fuel starvation in our mode of transportation.

One aircraft manufacturer has looked at this issue and did something about it - why guess if the tank you are switching to holds fuel.   

Cirrus Aircraft has incorporated accurate fuel level - and with accurate fuel level you may eliminate switching to an empty tank.   

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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.

Like Cirrus Aircraft - Vulcanair uses CiES Fuel Level Senders - Exclusively

The entire article may be viewed at:

Vulcanair's New V1.0 Four-Seat  Airplane

April 10, 2014

By Paul Bertorelli Editorial Director

At Aero 2014 in Friedrichshafen, Germany, the Italian company Vulcanair announced a new model called the V1.0 that's meant to be positioned between light sport aircraft and the Cessna 172.  At a $250,000 projected price, it's far less expensive than the Skyhawk.  Vulcanair's Remo De Feo gave AVweb a briefing on the new model.

Our CiES digital fuel senders interface with the JPI 930 installed in this aircraft.

Click Here for Video

© Copyright 2014 AVweb. All rights Reserved.

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.  

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

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.