GA Accidents-Fuel

[Bennett]

Thank you for the link. Looks like accuracy is plus/minus 6% at best. Not good enough to depend on, but still one more gross check.

[fuellevel]

1 hour ago, DXB said:

Bennet - yes quite a bit of hysteresis lag in that gauge design.  I developed a wifi interface to that gauge - iPhone app  - hard to get wires to it however - maybe battery power? 

[DXB]

7 hours ago, fuellevel said:

This pilot was venting fuel overboard when the tanks got down below 10 gallons.   This pilot is not the only pilot to have experienced this aircraft issue,  Remember the Cherokee landing on video in California late last year.   And the accident that brought this to my attention.   This is an aircraft issue, not a pilot issue .  The gauges aren't the issue here, except if this pilot realized the implication of being so far off of his plan fuel wise, with his destination right in front of him.

 http://www.daytondailynews.com/news/news/local/area-pilot-whose-plane-crashed-in-tennessee-recove/ngJD5/

 

2 hours ago, DXB said:

I read what I could find about this accident and am trying to learn more about this fuel venting issue but am coming up empty. What is the evidence that fuel was dumping overboard in this and other fuel exhaustion accidents conventionally attributed to pilot error? 

 

40 minutes ago, fuellevel said:

 There are some incidents with fuel starvation that boggle the mind - in re-run they appear to be suicidal.  Marketing wise the added safety of working fuel quantity would apply to Cessna 172's, Bonanza's and PA-28's.    

Second- I only have a working idea on the cause - Piper has a mandatory service bulletin for deteriorated vent tubing, with fuel smell in the cockpit and venting into the wings.   I don't know the mechanism or correlation of low fuel and the potential for a siphoning action 

You made a definitive assertion, in boldface underlined font,  that fuel venting from this PA-28 pilot's wing caused his accident - a very provocative conclusion.  Not finding any published indication of this having happened, I asked for evidence.  I've read your full response carefully, and I don't see any evidence being offered.  You don't even offer a clear mechanism by which the fuel might have vented from his tanks. Half-formed speculation in ones own mind can be productive, but stating those speculations as the bold assertions in the service of your product seems either dishonest or delusional. 

 

[fuellevel]

2 hours ago, DXB said:

Just now, DXB said:

You made a definitive assertion, in boldface underlined font

I have been transparent in this - the only thing you can surmise from afar is that fuel left the aircraft, or got burned up in the engine.     I am emphasizing this element - It is a conclusion but there only very narrow causes for an aircraft to dramatically change fuel flow in flight.  It may not be the only conclusion to support the record presented and I am open to speculation from any quarter.   It may just be me - but I see no evidence to support a pilot caused starvation issue from Brooks County to just shy of his destination.  

We have a clear record of fuel burned from this pilot referencing a gauge - that fuel burn changes dramatically without any change in airspeed in that he is where he is supposed to be by plotting his course at his average airspeed.   No dramatic change in engine power.    But his fuel burn as indicated by his declarations of fuel onboard are not consistent at the last leg of his trip, and everything else is. 

There isn't a clear visual reason for this just looking at the Fuel system diagram because I am not the FAA investigator not was I on the scene.  At this point,  I can't see the mechanism to allow that venting to happen.     We do have on the Piper forum, lots of discussion of a venting issues that don't make sense looking at the diagram. 

In both cases it was a reported pilot error.   And I see no clear evidence for pilot error other than trying to use the capability of the aircraft.    My feeling, but I don't know  is that you are arguing equally for pilot issues being the primary reason in this case.

I am emphasizing that the pilot made no adverse decision from the record.

[carusoam]

Phil,

When fuel goes missing, it often leaves a huge blue stain where it was last known to be...

is there any record of a blue stain or a reason that the blue stain doesn't occur?

if the mixture knob was left in for the whole flight, where would the flight have ended?

 

Bennet,

I have used my wing gauges while filling and compared against the fuel pump.  Wing gauges are marked every five gallons  the gas pump is measuring to the second decimal place...

If I am loading 50 gallons total.  I can easily fill both sides evenly to start the flight in a nice balanced way.

Overall my analog gauges are accurate, they just lack the precision to let me know to the closest gallon how much is left in the tank.  That is going to need a digital display added for me.

For that accuracy I use FF.  The fuel used has been well calibrated to be accurate within a gallon.  The easiest way to goof up this precision is to ignore the reset the fuel used before flight step.  Or accidently hitting the reset button.  It is a dual purpose button with push and hold to reset.  That would be the moment I would really like a more accurate FL gauge.

i am still planning on having 15 gallons left in the tanks (100+ total) when I'm done flying for the day.  Pretty visible on a pair of analog gauges under ordinary conditions.  

Best regards,

-a-

Best regards,

-a-

[fuellevel]

carusoam 

They didn't look in either case.  In the record the owner indicated that a fuel flow warning would be nice.   Interesting fact is that due to the SB for the wing spar the tank was to be removed and the vent lines check and the fuel sender gaskets replaced.  The fuel sender fiction is to be checked as well.  This is to be done at 7 yr intervals.  Trolling the Piper forum lots of leakage descriptions and blue stains, some of which occur through the sender wire attachment and sender gasket    This is a leather seal on Stewart Warner senders.  

I need a tank to play with and pressurize and depressurize at that critical fuel volume.     I am doubly curious now.  Worth buying a tank to find out.   It has to be pretty low in the tank. 

I forgot that I should look at the Canadian reports - they do a very good job with fuel related incidents 

The oblong float is a issue - I have received these in the mail frozen in manner the picture shown 

[carusoam]

Siri seems to have swapped friction for fiction?

older Mooney tank floats used cork seals that last about 40 years. A real opportunity for some Mooney owners to take a look at what they have and decide on the direction they are going to go.  The end of the tank is accessed from the cabin interior.  It requires a fabric 'panel' to be removed.  Lots of blue when the cork leaks.  Sidewall stain, carpet stain....

Best regards,

-a-

[Hank]

You may be able to buy a Piper tank to study. The only way to buy a Mooney tank is to buy either a scrap wing with intact tanks, or a whole plane. The tank is a sealed area between the leading edge, spar and some wing ribs, with the skin forming the outer boundaries.

Keep us informed, we are curious . . .

[fuellevel]

Yes - actually they are reasonable on Ebay - typically with rips in the attachment holes.    On Ebay I am seeing lots of issues 

Fuel staining around the sender, torn and broken flexible lines.  broken fuel vent tubes.   The vent is high up and so is the check valve.

I actually found a Mooney example in the record - where blue stains were present around the vent tube.   No explanation why - lots of fuel missing 

I am finding a few PIREPS - especially on Archers for fuel loss anomalies that occur at 9000 ft and then cure themselves on the next flight at 3000 ft 

Something on the order of 10 to 20 gallons - startling

I am really at a loss for rational ideas:

• fuel slosh from turbulence reaching the vent . - My Cirrus Garmin data illustrates pretty wild fluid motion down low in turbulent conditions. 
  • A lot of vents nearly all  for sale were compromised in some manner  
  • The Mandatory Service bulletin should have addressed these issues and also established the function of the fuel sender.
• My father - a really old A&P and former IA when all of these were new - says he has seen blocked vents allow the draw atomized fuel off the top of the fuel tank
  • I have seen this dramatically displayed  on a loose fitting cap on Beechtalk - full tanks however  
  • I the not seen this happen - and there should be a tell tail somewhere. 
• Fuel loss at the pump ( the engine ran - however) 

I will find it - I always do 

 

 

[DXB]

On 6/26/2016 at 8:17 PM, DXB said:

You made a definitive assertion, in boldface underlined font,  that fuel venting from this PA-28 pilot's wing caused his accident - a very provocative conclusion.  Not finding any published indication of this having happened, I asked for evidence.  I've read your full response carefully, and I don't see any evidence being offered.  You don't even offer a clear mechanism by which the fuel might have vented from his tanks. Half-formed speculation in ones own mind can be productive, but stating those speculations as the bold assertions in the service of your product seems either dishonest or delusional. 

 

On 6/26/2016 at 8:45 PM, fuellevel said:

I have been transparent in this - the only thing you can surmise from afar is that fuel left the aircraft, or got burned up in the engine.     I am emphasizing this element - It is a conclusion but there only very narrow causes for an aircraft to dramatically change fuel flow in flight.  It may not be the only conclusion to support the record presented and I am open to speculation from any quarter.   It may just be me - but I see no evidence to support a pilot caused starvation issue from Brooks County to just shy of his destination.  

You have not been clear and transparent in your communication on this thread.  Let me again point out what you saw fit to post by quoting it directly:   "This pilot was venting fuel overboard when the tanks got down below 10 gallons.   This pilot is not the only pilot to have experienced this aircraft issue,  Remember the Cherokee landing on video in California late last year.   And the accident that brought this to my attention.   This is an aircraft issue, not a pilot issue ."   Subsequently backing off by saying the fuel either left the aircraft or got burned in the engine simply cannot make the initial statements justifiable.  Without smoking gun evidence, proposing that wide segments of the GA fleet have a previously unknown vulnerability causing to vent fuel overboard demands cautious, tentative language and testable hypotheses. Instead you tried to support a speculative idea in the over-emphatic tone of a wild-eyed conspiracy theorist.  

Why am I making such a big deal of this?  It's just the internet after all, where anything goes. Plus rank amateurs like me and various other prickly personalities make unsupported declarations on here all the time.  Well, it's different when someone who claims 30 years industry experience and supplies fuel system components to a major aircraft manufacturer engages in such behavior. Your apparent authority in this area, combined with a major conflict of interest, makes it far more reprehensible. 

[fuellevel]

DXB - the level of discourse is important.  I am presenting a very unique perspective to shine a light on an alternative way of thinking about these problems.  They are not so cut and dried as I think in your responses to me make me believe is your viewpoint.    Your point of my extensive experience, which is correct.  I am considered an expert in this field to to address difficult system problems and come up with viable solutions.   Mooney management brought this opportunity to my table because they trusted me to make it a solution for their needs. 

So let me lift the curtain a bit. I am definitely expecting a typical response on this article.  But it is not all you see and it makes a good example for illustrating how hard we cling to the opinion most fuel accidents are a pilot issue.  

My point is that you can't find, what you aren't looking for.    

So that you know that I am listening to you carefully  - of the 44 records of Mooney Exhaustion event in the NTSB record - almost 20 have some element of aircraft failure as a link in the chain.   Granted some of those are non functional fuel indication - empty tank full gauge reading for example. 

I have had extensive conversations with the pilot of this accident, who also doesn't have a physical answer about why this happened, only that it happened in real time before his eyes.  He was frustrated as well by the pencil whip investigation, the engine settings he was in control of did not change in the direction or as radical as the record indicates.    Believe me - this pilot has credentials and awards we would all hope for and he is still an active pilot.  Hopefully I can divulge more.    

So as an engineer - do I know exactly what happened, no - did I cross everything else off the list,  yes I did.   Be careful what you ask of an engineer  - Am I 90% sure - hell yes,  am I 99.9% sure ???? .   DXB, No, I don't have a credible physical mechanism for removing that much fuel in that time frame.  

I am looking and there are clue crumbs out there, but no smoking gun.  It is difficult to deal with inadequate investigative efforts as you have to laboriously piece together evidence.

The Cherokee on the roadway in California is another example, where the plan and facts divulge to create a very public accident.

But to illustrate the bias inherent in discussing these incidents - that pilot is not the pilot example I chose to use to illustrate.  

I highly doubt that I am reprehensible.   I fee that you are sifting through information to vilify me and my purpose here.

Work with me and maybe tomorrow I will be 99.9% sure. 

I believe I have a key to more informed solution,  But my greatest fear that the ingrained bias in the aviation community won't let that message be heard.  

 

[DonMuncy]

I have held off from jumping into this fray as long as I can.

I do not claim to have read (or perhaps be able to understand) all the information concerning the fuel level indications, but it appears to me that the “tone” of Fuellevel’s posts is that the widespread use his products would substantially change the number of crashes/deaths due to fuel starvation. (Don't get hung up on the starvation term. Use whichever one you prefer) I don’t have any data to support my opinion, but that opinion is that this is highly unlikely to be true.

Is more accurate fuel level indication a good thing? Absolutely yes.

Are his products capable of better fuel level indication? Very likely true.

Would I use his senders if I needed to replace one of mine? Likely, it the price differential was not too great.

Would I pull my senders to put his in? No.

Would the widespread use of his products prevent some crash/death? Maybe somewhere, sometime.

But; they won’t keep pilots from doing stupid things or using poor judgment; they won’t cure the deficiencies in the gauge itself; they won’t prevent the loss of fuel from leaks, improper fuel cap seating, etc.

Perhaps all these things are what he is trying to convey, but again, the tenor of his posts goes far beyond this.

Just my opinions. Worth what you paid for them.

[PMcClure]

When I was in school, I had an old car with no fuel gauge or odometer. I drove ALOT and only ran out of fuel once, and that was in front of a gas station. I kept a log book in the car and tracked miles and mileage at every fuel stop. I calculated mileage by using mile markers on the road or guesses in town.  I eventually was able to create a fairly accurate estimate of my actual fuel consumption. I also left a 5 gallon reserve because I could never be 100% certain of how much fuel I had. I restored that car and added a new sender and gauge. But ran out of gas on my first tank. Seems the siphon tube was shorter on the new sending unit showing 5 gallons left. But it was all  unusable due to the shorter tube. oops....

Now I have a new car that gives my available fuel down to .1 gallon and available range, with warning lights and finally an annoying ding when it gets to 50 miles. I regularly challenge that gauge to see how far I can get. More accurately, my kids and wife seem to return my car to the driveway as close to 0 as possible and I am left wondering if I will make it to the gas station 10 miles away. I am ashamed to say that I have run out of gas 2 times in 5 years. My point being that accurate information is valuable and accurate gauges make it easier to get more accurate information. But ultimately I agree with Don, it won't solve the multitude of accidents where pilots try to fly 6 hours with 5 hours of gas. More better is better but nothing is perfect. It comes down to good decision making and risk avoidance. 

[fuellevel]

I will make it simple and visual.  The Belgians did this one. 

Where in the tree would you place accurate fuel level indication

as an adequate warning of the issues presented. 

We help good pilots make better decisions -  Bad pilots are not our market

 

 

[Guest]

This one will soon be as long as the (he who shall not be named) thread.

Clarence

[Hank]

3 hours ago, M20Doc said:

This one will soon be as long as the (he who shall not be named) thread.

Clarence

It alright, Clarence. The Dark Lord doesn't hang out here. Besides, didn't Harry eventually finish him off? I never read the last two books . . .

[fuellevel]

I can only guess    

 

[Guest]

6 minutes ago, Hank said:

It alright, Clarence. The Dark Lord doesn't hang out here. Besides, didn't Harry eventually finish him off? I never read the last two books . . .

You're thinking of Hogwarts, I'm thinking Iowa.

Clarence

[MyNameIsNobody]

13 hours ago, M20Doc said:

You're thinking of Hogwarts, I'm thinking Iowa.

Clarence

Both FUNNY HA HA and FUNNY STRANGE.

Must be awful to be haunted by a single thread that is now years old...

The Horror....

[Yetti]

OH this is fun I will jump in.   Not sure how Mooney gauges work but driving Fords growing up it is a very well know fact that they read full for a long time then the last 1/4 of the tank goes really fast.  Not sure if it is the angle of the float arm swinging through the arc or impedance working it's magic.

Float guy says the pilot was burning 9 gallons per hour.   What facts are there to support this claim?

If it is only the fuel gauge then this is an assumption that the pilot had going that was probably wrong.  Previous burn rates does not matter since he could have leaned out the plane differently.

Knowing the Corpus area a bit.  It always has a very strong onshore wind.   I would say he ran into a head wind and started to burn more fuel, and his gauges were at the bottom and showing less fuel at a faster rate then the top of the tank.

[fuellevel]

I was warned by the Director of Flight Operations at Cirrus to look at this from a pilot perspective 

• Assume the fuel gauges are crap
  • In this instance float guy (I prefer AMR guy) believes the pilot
    • Pilot is ex military, wrote and taught classes on aircraft instrumentation.  
    • Aircraft is airworthy including working fuel indication.  
    • Non working instrumentation of any type was not acceptable
      • The pilot made sure of that.   
• The above assumption is a sad state of affairs

So that premise that all fuel gauges are crap in aviation is a pilot perspective.   In this case, that assumption is wrong

• So
  • Yes he hit winds of 15 knots head on at the end of the trip on descent from 7,500 ft - his fuel burn was 20 gph increasing to 50 mph indicated
    • But here fuel is moving away from the sender on descent - Gauge reading is compromised.  Sender is on the aft wall of the tank 
    • Leveled out the fuel burn is now approx 40 gph
  • Max fuel burn firewalled PA28-180D is 16 g/hr 
  • His gauges were calibrated per the Piper maintenance manual only better which lists a reasonably tight tolerance for gauging 
  • The gauges had proved to be accurate on other cross country flights - throughout the range, level flight
  • Assume you aren't a pilot with a long history of looking at crappy fuel gauges.
    • Assume you didn't tolerate faulty instrumentation in your aircraft. 
  This pilot operated the aircraft uniformly - no need to adjust for this cross country flight, I did ask.

Now what do you see. 

[Yetti]

Never said the gauges were crap.  What I said was they are not linear in their reading.  Also the needle on 0 in a mooney gauge is not an empty tank.  The needle pointing to the dot left of  the "0" is empty.  The Needle pointing at 0 is about 12 gallons.  It has taken me about a year to learn this. 

We still have no supporting facts that on this day on this trip  the plane was burning 9 gallons per hour. and lack of an unsupported theory of venting an almost empty tank (maybe on a full tank, not an empty one) We should probably just go with he was burning more than 9 gallons and that is why he ran out of gas.  Had he stopped 1/2 or 3/4 ways he could have not been the subject of several pages on the internet.

Working with my A&P we developed the phrase "Degrees of accuracy"   Does the magneto timing beep just a bit before or spot on or can you tell the difference given the heat of the day and speed of sound and reflex of eardrum to brain.   I taught him the phrase "Tractor Tight"  the little extra bounce you give the wrench when tightening a tubing fitting.

I have not tried this theory out yet, but the Ford Extended Edition has a larger fuel tank than the regular one.  They did not reset the fuel computer for the larger tank best I can tell.  The good news is that this will keep the electronic fuel pump submerged in gasoline which keeps it cool and keeps from burning out.

[PMcClure]

Personally, I suspect all my instruments. To quote someone on this site who seems to know what they were talking about:

"In over 40 years of flying, and over 15,000 flight hours including over 6500 at night, I've learned to be flexible, trust nothing, adjust the safety margins as conditions change, and ALWAYS leave yourself an "out"

I want to be that guy. I don't rely exclusively on any instrument, even the AI. If I had an Angle of Attack gauge some people tell me I will never stall spin. I think that is a crap argument, too. I don't trust my ASI, my gps or even my door latch with my life.  Don't we constantly have to cross check and verify to be a good pilot? My job a as "good pilot" is to make sure I have enough fuel to complete the flight with enough reserve to be safe and legal. The fuel gauge is never a part of that equation. It's only there to make me feel good about my progress. I verify I have 5 hours of fuel and land in 4. Headwinds, fuel gauges, etc... don't really matter to me. And if I have a leak develop in flight, then, well I still have 10 gallons in my other tank. Engine stutters, I stain my britches, switch to the other tank and land immediately. That is my out incase I was stupid or didn't plan for unseen events. 

Plain and simple  - it's the pilots fault if he runs out of fuel. Not the fuel gauge. I'm all for good fuel gauges, give me the best. But even then, I am not going to rely on it. 

And to add something, in the 7 years I have been flying, I have had an ASI fail, 4 AI's fail, a DG, GPS, A/P, trim, Vacuum pump, etc... All these instruments and devices are crap in my opinion. That is why I don't rely on any of them. 

Edited June 29, 2016 by PMcClure

[fuellevel]

Again - the different between my perspective flight engineer and pilot are --  apples and oranges 

Crap (engineer speak) - if the gauge oscillates - crap

if 20 gallons is off 1/2 needle width of the 20 gallon tick mark - crap 

I deal with manufacturers - that is what they expect.    That is what I have to expect.

This is the calibration we had to meet with our floats for the Airbus AS350B3 helicopter - fuel weight 900 lbs - 150 gallons - single un baffled tank 

Crap is the indication that falls out of the blue and violet maximum error lines.  

We had to fix the deviation shown at full and bring the bottom closer to the perfect line.

I have a different perspective and expectation of fuel quantity.    

Pretty much blows - "Only accurate at zero" out of the water 

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

I chose this incident carefully 

Very clearly - fuel gauges were of little help to this pilot.   He noted a bad trend and recorded it, but failed to act on the information in front of him and continued flight.  He was using his watch as the indication of trust fuel wise.  (not in the record, I asked) 

Nobody is out to fix bad pilots - bad pilots will do any number of things - Take drugs, drink and fly, defer maintenance, defer training and ignore indication meant to point out issues with the aircraft.   Nothing will fix bad piloting, they shouldn't have been granted a license.  

The concept is to make good pilots better or more succinctly point out issues with the aircraft prior to an accident - break a link in the chain. 

I think the idea here is that you believe I didn't go to the same church as you or listen to the same sermon.  (Synagogue, Mosque) 

That assumption is wrong. 

 I am a bit more orthodox when it comes to any cockpit information, I have to be.  Just like you have to be good pilots.  There are no good alternatives. 

•    Trust but verify is an aviation watchword for any activity under the umbrella. 

[PMcClure]

I guess I just don't get it. I think the guy had a forced landing because he didn't properly plan. The NSTB says relying on fuel gauges was a contributing cause, not that the fuel gauges were inaccurate was a contributing factor (from your blurb). It was because he relied on them instead of using proper planning and decision making. Your nifty units will fail one day too and if someone depends solely on them to determine how long they can fly, they may die. I think I would be more interested if you just say you have a better replacement or OEM unit and avoid the whole discussion about it reducing accidents.