Psychology of fuel management

What psychology? Fill up every time you land and never fly close to the reserve ring. Double check with fuel gauges and common sense. I guess you could be more efficient carrying less fuel, but how economical is crashing a plane over fuel starvation? (One idea I took away from a Barry Schiff talk.)
Apologies for blurry photo.Fuel Rings.jpg
 
My personal minimums on fuel borderline on psychosis. I've never been in a situation in an airplane where I've felt like I was pushing reserves. I've never pushed reserves. A three hour reserve on a two hour flight seems about right to me.

I've never run out of gas in anything, car, motorcycle (caveat following), lawnmower (intentionally), M151 Jeep, M35 Deuce, or anything else like that.

Caveat: My BMW 1200RT had a fuel level indicator. It was precise. It was subject to failure but I didn't know that until it failed. I always set the trip odometer to established fueling stops but got complacent with the fuel gauge, and found myself out of gas with a registered 1/4 tank. It failed at 1/4 tank.
 
I agree, an hour reserve feels about right to me as a "don't dip into that, period" level. However, that might be easier for me to say than in some situations, since for me it's 14 gallons out of 82.
 
deyoung said:
I agree, an hour reserve feels about right to me as a "don't dip into that, period" level. However, that might be easier for me to say than in some situations, since for me it's 14 gallons out of 82.
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Fuel management is easy when tanks are full. But my base has no fuel. So usually only trips start at "almost full." Once I made the 10nm flight for fuel (I was pretty low), and had to wait almost an hour for someone to show up and pump it (full service only, and I don't know my way around a fuel truck). It was very tempting, the longer I waited, to hop another 15nm to the next field, whuch had self serve. But that would have cut it too close . . . .
 
Interesting - I had the opportunity to rewrite the FARS on Fuel Quantity and I with others removed the ambiguous language. Basically, it reads from full to empty where full is the placard exact value found on every certified aircraft wing and zero is the end of usable fuel . As for the official reference to fuel gauge accuracy Advisory Circular 23.17 which references the TSO and other guidance for the accuracy standard.

What is more telling is that if we applied the same defective logic to say another required instrument - Tachometer for example. A Tachometer that is only accurate at zero is a broken tachometer.

Strangely every pilot would say that that last statement was true - but will state that fuel gauges should meet that same criterion and never think twice.

Fuel gauges should work in the aircraft they should show within a gallon and half of true fuel quantity in a 50-gallon total fuel volume or 0.75 gallons per tank. Yes that is the standard

if you doubt it google any Piper maintenance manual and references the tolerance established in the manual for the fuel gauge calibration. This isn't a new or unknown requirement to people who have or are certifying aircraft.


We rely on sticks, tubes, totalizers and watches because we have allowed required instruentation to be substandard or become substandard equipment ie not airworthy - we rely on workarounds because the system that should work has
been allowed to deteriorate to a point of uselessness.

That is the frank truth and the source of many of the common edicts we were told from the get go. - Only accurate at zero, dont trust your fuel gauge ...

Fact - Most pilots 99.8% preflight fuel quantity with a visual reference on a cross country flight, most pilots 96.5 % do the same for a short flight
Fact - Totalaizers have had no impact on fuel starvation or exhaustion statistics.

It isn't stupid pilots that run out of fuel as pilots with advanced ratings - CFI, CFII, Commercial, ATP make up 50% of the fuel starved and exhausted statistic.

While we have clamored for exact GPS geophysical reference in every cockpit with technology - we appear reluctant to use technology to provide a fuel quantity system that works in aircraft or maintain a system so that it is functional

denverpilot is right
 
Scott Philiben said:
Interesting - I had the opportunity to rewrite the FARS on Fuel Quantity and I with others removed the ambiguous language. Basically, it reads from full to empty where full is the placard exact value found on every certified aircraft wing and zero is the end of usable fuel . As for the official reference to fuel gauge accuracy Advisory Circular 23.17 which references the TSO and other guidance for the accuracy standard.

What is more telling is that if we applied the same defective logic to say another required instrument - Tachometer for example. A Tachometer that is only accurate at zero is a broken tachometer.

Strangely every pilot would say that that last statement was true - but will state that fuel gauges should meet that same criterion and never think twice.

Fuel gauges should work in the aircraft they should show within a gallon and half of true fuel quantity in a 50-gallon total fuel volume or 0.75 gallons per tank. Yes that is the standard

if you doubt it google any Piper maintenance manual and references the tolerance established in the manual for the fuel gauge calibration. This isn't a new or unknown requirement to people who have or are certifying aircraft.


We rely on sticks, tubes, totalizers and watches because we have allowed required instruentation to be substandard or become substandard equipment ie not airworthy - we rely on workarounds because the system that should work has
been allowed to deteriorate to a point of uselessness.

That is the frank truth and the source of many of the common edicts we were told from the get go. - Only accurate at zero, dont trust your fuel gauge ...

Fact - Most pilots 99.8% preflight fuel quantity with a visual reference on a cross country flight, most pilots 96.5 % do the same for a short flight
Fact - Totalaizers have had no impact on fuel starvation or exhaustion statistics.

It isn't stupid pilots that run out of fuel as pilots with advanced ratings - CFI, CFII, Commercial, ATP make up 50% of the fuel starved and exhausted statistic.

While we have clamored for exact GPS geophysical reference in every cockpit with technology - we appear reluctant to use technology to provide a fuel quantity system that works in aircraft or maintain a system so that it is functional

denverpilot is right
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Those are some excellent facts and sobering observation. I know I go through my checklist which has “Fuel gauges” and I pay almost no attention to them other than that they appear to be working and show an approximate level based on my inspection. After that it’s all time based analysis.


Sent from my iPhone using Tapatalk
 
Good points. Totalizers and stopwatches do not tell you if you have a leak. Only a functional, accurate fuel gauge will do that.
 
I suppose the only downside for folks such as myself that have never run out of fuel in any vehicle, land, sea, or air, is that we'll be a bigger flaming spectacle if we screw the pooch.
 
Cogito said:
What psychology? Fill up every time you land and never fly close to the reserve ring. Double check with fuel gauges and common sense. I guess you could be more efficient carrying less fuel, but how economical is crashing a plane over fuel starvation? (One idea I took away from a Barry Schiff talk.)
Apologies for blurry photo.View attachment 65128
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How do you fill up every time you fly if your destination doesn't have any fuel? Or if your destination has you in the trees if you were to fill up?
 
I will soon be traveling half way across the country to pick up my airplane and bring it home. The eight or so stops are based on my zero-wind fuel calculation and I have fat fingered the fuel burn to help assure success. I'll be forced to make the flight solo in order to stay under gross weight with full fuel.

The plane has two mechanical gauges in the wings and I have no idea if they even work, so I will have to learn the system on the fly as I make it through the first few fuel stops. Am I making the planned stops shorter for the first few legs to ensure some kind of psychological/emotional safety factor? Nope. That would be counter productive because I need to learn the true range of the plane as quickly as possible. Will that cut into my margins? Probably not, since my initial planning already has some buffer in it...

Since my flight will be from West to East, I'll most likely have a tailwind to factor in to my resulting range calculations. I have no electronics in the plane other than a comm and a transponder, so the whizwheel and the tablet will be my fuel computer.

I'm more worried about weather than running out of gas, anyway. Oh, and finding great Mexican food. (OR/CA/AZ/NM/TX)
 
idahoflier said:
I never have, especially after I learned the FAR's only say they have to be accurate on "E". My aircraft has an approx.
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Posh. Untrue. The rules don't say anything about the accuracy of fuel gauges at all. What people keep misinterpreting as such a statement is the rule that the E mark corresponds to zero usable fuel (as opposed to bone dry tanks).

I always use the most PESSIMISTIC of the following:

1. My fuel gauge.
2. My fuel flow meter.
3. My preflight calculations as to fuel burn (and my watch).
 
IK04 said:
The plane has two mechanical gauges in the wings and I have no idea if they even work, so I will have to learn the system on the fly as I make it through the first few fuel stops. Am I making the planned stops shorter for the first few legs to ensure some kind of psychological/emotional safety factor? Nope. That would be counter productive because I need to learn the true range of the plane as quickly as possible.
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Couldn't you do that by running one of the tanks dry? :devil:
 
I’m used to wooden sticks and a fuel gauge that is basically just a “canary in the coal mine” kind of device that so long as you don’t have to ask yourself “why is it doing that” you’re probably okay. It wasn’t until I got a modern JPI with a very accurate fuel flow totalizer that I had a close call because turns out it’s only as good as the idiot who programs it. The danger is they are so good you come to trust them much more than you did the old gauges but there is still the human element in the chain that can screw you up.
 
IK04 said:
This topic has led me to do some fuel tank measuring on my new airplane:

With both tanks completely empty and the plane sitting on all three wheels, I'll add one gallon at a time in each tank and measure the depth of the fuel with a dipstick. With the stick vertical and touching the bottom of the tank and the rear of the filler neck, I'll make marks for every gallon in each tank, alternately. I'll also take a photo of the respective fuel gauge after each gallon.

Since my useful load is restricted by my body weight being 70 pounds higher than it was last time I flew a C-140 (getting old and fat sucks), I'll need to know exactly how much fuel is in my tanks in order to stay under max gross weight with a (skinny) passenger!

Following that endeavor, I'll fly the plane on a smooth day and run each tank dry (on separate flights, of course) to see how the fuel gauge indicates in the level, in flight attitude. That will also make me familiar with how the plane reacts with an empty tank.

I plan to take my little airplane on many long flights in the future, so fuel management will be a primary consideration in my flight planning. I believe in using every drop of fuel to get where you are going and I also believe in knowing exactly how much fuel you have in order to make it.

This should be fun. :D:cool:
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IK04 said:
The plane has two mechanical gauges in the wings and I have no idea if they even work
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Well, you better make sure they do before you fly it. Fuel gauges are NOT optional equipment on the 120.

Note that when setting up your dipstick that you don't calibrate it with gallons from empty, but rather gallons down from full. Empty is zero-usable not bone dry.[/QUOTE]
 
I remember reading a crash report where they had found the guys preflight planning that said he had 7h30m of fuel. At about 7h40m into the flight, he ran out. I gave him a small bonus for nailing the fuel duration. Too bad he wasn't quite at the runway when it ran out.
 
I use the scheduler function on my 430W to give a fuel change message every 30 minutes. It's a prompt to switch tanks and and keeps you aware of fuel management. Tablet Apps and portable GPS units have similar timers. Other than that, I rarely operate at gross weight, so I generally top off. Finally, I have found that my bladder duration is about 3.5 hours and my fuel duration is about 5.3 hours. Every time I my bladder duration has reached BMAX, I top off the tanks. Barring a serious fuel leak, I think I'm good.
 
From the beginning, I learned that old Cessna fuel gauges are not to be trusted. Since then, I've always "sticked" the tanks before every flight. I have also always preferred to stick to a more conservative fuel reserve. I can't say what it is in my psyche that makes me this way, but I have never had the urge to just keep going or try to make it just a little further. I plan fuel stops with ample reserve, and I stick to it. If I don't make it to the destination when time is up, I find a place to land. It's hard for me to understand why folks even cut it close. It's a dang airplane! You run out of go juice, and it's a dire situation with the gravest of consequences. Since I bought my 182, I've never landed with less than 18 gallons, which is close to 1.5 hrs of fuel. Call me crazy, but I like big margins. I enjoy living.
 
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deyoung said:
I agree, an hour reserve feels about right to me as a "don't dip into that, period" level. However, that might be easier for me to say than in some situations, since for me it's 14 gallons out of 82.
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One hour never made me feel comfortable until my current Mooney. Six hours of fuel on board and a JPI with the upgraded sensors. It not only measures extremely accurately to tenth of a usable gallon, but presents it in every way you can imagine including MPG over the ground. Now that I have that kind of technology, my 70 year old bladder won’t let me take advantage of it.
 
OkieFlyer said:
From the beginning, I learned that old Cessna fuel gauges are not to be trusted. Since then, I've always "sticked" the tanks before every flight. I have also always preferred to stick to a more conservative fuel reserve. I can't say what it is in my psyche that makes me this way, but I have never had the urge to just keep going or try to make it just a little further. I plan fuel stops with ample reserve, and I stick to it. If I don't make it to the destination when time is up, I find a place to land. It's hard for me to understand why folks even cut it close. It's a dang airplane! You run out of go juice, and it's a dire situation with the gravest of consequences. Since I bought my 182, I've never landed with less than 18 gallons, which is close to 1.5 hrs of fuel. Call me crazy, but I like big margins. I enjoy living.
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+1 for go-juice
 
Universal Fuelhawk M20E

I have a 1964 Mooney Super 21 and the fuel dipstick that came with my airplane proved to be inaccurate by more than 2 gallons. I did some research and found a 2010 post that gave fuel level heights for making a dipstick using a paint stir stick. I tried that but fuel on sticks tend to wick some and makes precise readings difficult so I decided to get a 16-inch universal fuel drop tube from J-Air inc. They call it a Universal Fuelhawk. It comes with a set of instructions, table, and graph for calibrating the fuel tank on your airplane.

The instructions say to start with the fuel tank nearly empty and add 5 gallons at a time to plot a calibration graph. Since my tanks were just filled I elected to start full and drain the tank 2.5 gallons at a time instead. It took me a couple of hours to set up collect my data, then I transferred all of it to the graph attached here. Here is what I did:

I started with 5 clean 5-gallon buckets that I had bought previously. 5-gallon buckets are tapered, so I used a caliper to get the exact dimension of the diameter of the bucket at different heights. I extended the caliper inside the bucket at the height desired, locked it and measured it with a tape measure outside the bucket. The bottom diameter was 10-¼ inches, at 12 inches height was 11-¼ and 13 inches height was 11-5/16. From these dimensions I calculated average diameter at 0-12 inches, 0-6 inches, 6-12 inches, 12-13 inches, and 0-13 inches. I then calculated fuel amounts for each average taken. I compared the partial bucket volumes to the total volume calculated to determine how much error I had. The total average was 10.78125 dia and for 13 inches that calculated to 5.1376 gallons. Av Dia squared divided by 4, times 13 divided by 231. ((D^2)/4) x 13 / 231 = Gallons. The partials added were 2.2491 + 2.4684 + 0.4327 = 5.1502. 5.1502 / 5.1376 = 1.00245 or 0.245% error between the two methods.

As best as possible I marked the 2.5 gallon mark with an equal sign so that light shining from the outside of the bucket will highlight a space between the lines. I used a 5/16 rubber fuel hose to siphon fuel out of the tank into the bucket and stopped at the mark. After doing this twice and pouring both into the same bucket I found they added to less than 5 gallons. The mark ended up being 2.445 gallons and I used 2.44 in my calculations. I measured the fuel height at 26 gallons (full) then 23.56, 21.12, and so on down to 6.48 gallons. I took 9 measurements. I put the fuel back in the tank through a strainer, making sure it remained clean. I then packed up and went to the office.

Using the calibration graph provided I plotted the fuel level and gallons remaining on the graph. I then connected the dots with a smooth line. I extended the line down to 5 gallons and created a height – gallons table in one gallon increments. I put all the data on the graph and added my bucket measurements and calculated volumes. The fuel level on the tube is marked every 1/4 inch and it is easy to read to the nearest 1/8 inch. The smallest 1 gallon increment is 3/8 of an inch, so a 1/8 error would be about 1/3 of a gallon. So now when I measure my fuel level I should know within 1/3 of a gallon exactly how much fuel I have. All that is left to do is to scribe level lines per gallon on the drop tube.

Hope this and the chart attached helps.

PS: I am working on scribing the lines on the tube and found the scale on the drop tube is actually 7/8 of full size. Go figure! Since all my measurements were taken with the tube, my chart is correct as long as I use the scale on the tube to scribe my marks.
 

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Scanning this long thread, there are several references to sight glass gauges being absolutely reliable.

I found out otherwise and ended up landing an old Aeronca Sedan 15AC seaplane in a swamp 5 miles short of destination. The wing root sight gauges were showing plenty of fuel on board but unknown to me was the tanks in that old Aeronca were Fuel Cells and the jury rigged fuel caps on the top of the wing were leaking air into those fuel cells slowly collapsing them. With only 100 hrs TT I had never heard of fuel cells before, and the effect they can have on fuel system operation and behavior. Fuel cells! - in an old airplane!

Asked 52 years later at the FAA Wright award program, my most important wise words of wisdom were - "You can never know too much about your fuel system".
 
I was taught to be conservative with flight planning, leave an hour reserve and land before going into reserves. Outside of a mechanical issue of losing fuel, I have never read a fuel incident that I can envision being in by following these rules.
 
We ran almost out of fuel in our rental camper in the Australian desert (don’t ask - I read the map and thought the area we were passing had a little town with gas station; it was not a town... :eek:). Ever since we are super conservative when it comes to fuel. I think we never landed with less than 1.5 hours remaining fuel...
 
Scott Philiben said:
Interesting - I had the opportunity to rewrite the FARS on Fuel Quantity and I with others removed the ambiguous language. Basically, it reads from full to empty where full is the placard exact value found on every certified aircraft wing and zero is the end of usable fuel . As for the official reference to fuel gauge accuracy Advisory Circular 23.17 which references the TSO and other guidance for the accuracy standard.

What is more telling is that if we applied the same defective logic to say another required instrument - Tachometer for example. A Tachometer that is only accurate at zero is a broken tachometer.

Strangely every pilot would say that that last statement was true - but will state that fuel gauges should meet that same criterion and never think twice.

Fuel gauges should work in the aircraft they should show within a gallon and half of true fuel quantity in a 50-gallon total fuel volume or 0.75 gallons per tank. Yes that is the standard

if you doubt it google any Piper maintenance manual and references the tolerance established in the manual for the fuel gauge calibration. This isn't a new or unknown requirement to people who have or are certifying aircraft.


We rely on sticks, tubes, totalizers and watches because we have allowed required instruentation to be substandard or become substandard equipment ie not airworthy - we rely on workarounds because the system that should work has
been allowed to deteriorate to a point of uselessness.

That is the frank truth and the source of many of the common edicts we were told from the get go. - Only accurate at zero, dont trust your fuel gauge ...

Fact - Most pilots 99.8% preflight fuel quantity with a visual reference on a cross country flight, most pilots 96.5 % do the same for a short flight
Fact - Totalaizers have had no impact on fuel starvation or exhaustion statistics.

It isn't stupid pilots that run out of fuel as pilots with advanced ratings - CFI, CFII, Commercial, ATP make up 50% of the fuel starved and exhausted statistic.

While we have clamored for exact GPS geophysical reference in every cockpit with technology - we appear reluctant to use technology to provide a fuel quantity system that works in aircraft or maintain a system so that it is functional

denverpilot is right
Click to expand...
 
I've never used a stick to check the fuel level in a plane. Why? The vast majority of my flying has been in club planes. One of the club rules is that you put the plane away with full tanks so the next member doesn't have to worry about fueling before he goes somewhere. The plane I have the most hours in is a C-172 with long range tanks. 50 gallons useable. At 8.3 gallons per hour that's 6 hours endurance. Far longer than my endurance. I gas it up when I land somewhere, which is typically 3 hours or less. Needless to say, I've never come close to pushing the fuel range in that plane. Our C-182P has 74 gallons useable. Long range tanks in that, too. At 12 gallons per hour that's also a touch more than 6 hours. The 182 is a bunch more comfortable than the 172, but even so I'm landing with far more than minimum fuel in that plane. I don't have a 6 hour bladder.

Part of my pre-flight before even pulling a plane out of the hangar includes a visual check of the fuel level in the tanks. As well as a check of the fuel gauges. I also check before leaving another airport if fueling was planned there. Paranoid? I guess, but in 20 years I've never come close to running out of fuel in a plane (or in a car, and I've been driving for over 50 years).
 
I have never so much as peered in the fuel tank of any turbine-powered aircraft I’ve flown, but know the quanity indication to be very accurate. In light, piston-powered airplanes, not so much—with anything other than full tanks, the quantity is vague, without a totalizer, the consumtion is vague. I own a couple of (antique) airplanes in which the quanity indication are entirely different when it’s on the ground or in the air. I much prefer a totalizer equipt machine like my Bonanza. After a two and a half hour flight the fuel I put in the tanks is within two tenths of a gallon. Does that mean I’ll fly it less conservatively? No, but I like knowing.
I can believe fuel exhaustion is maybe more likely to happen experienced pilots, if only because they’re more likely to operate the kind of varied machinery in which the fuel consumption and quantities are more vaque (totalizers notwithstanding). Turbocharged engine consumption can vary widely, depending on how it’s operated. Also, there are plenty of types of airplanes that don’t easily lend to knowing the fuel aboard by looking under the fuel caps—you simply can’t see the fuel unless it’s nearly full.
But I question your assertion that totalizers have done nothing to reduce the statistic.
 
I switch tanks when my JPI says I have 1 gallon left in them. Over the course of a flight, I will lose the ability to fly an additional 15 minutes. So instead of 6 hours of flight, I can fly 5 hours and 45 min. That's too long for me to hold my bladder anyway.

Doing that also gives me a bit of wiggle room if I do get distracted and forget to switch tanks right away at the 1 gallon mark.
 
"I've never used a stick to check the fuel level in a plane. Why? "...

There are several good reasons to stick the tanks. Not everyone fills up to full after every flight, so it is good practice during preflight to measure how much fuel you have vs how much you need before takeoff. If you are carrying a lot of cargo and/or passengers you need an accurate weight for weight and balance calculations. If you need a lighter load of fuel to carry more payload or to provide a larger safety margin on a shorter field, then having the tanks partly full before takeoff makes it easy to add just enough to carry your desired fuel load. It is easier to add fuel than it is to remove it to make your desired gross weight.

Every airplane, depending on loaded weight, weather, and density altitude, may find that favorite field requires more runway today than you might have expected. I make it a practice to check the required runway lenght using expected density altitude of the airports in the area I am flying. I do this for gross weight and less than gross to determine if carrying less fuel us helpful. No, I don't do it all the time, but I do for every XC flight especially into an unfamiliar area.

Fuel is heavy and more weight burns more fuel. Why carry 5 hours of fuel for a 1 hour flight? If you are just up for some pattern work why have full tanks unless it is windy and the added ballast helps handling?

I am not saying that flying with full tanks is a bad thing, but it is not necessarily a good idea for every flight. We as pilots are responsible for the safety of each flight. We are supposed to know before we leave the ground that we can complete the flight safely. It is deceptively easy to overlook something that could cost you your life.

One of those could be landing too heavy and too fast on a hot day on a field too short for an acceptable safety margin. KEZF Aug12, 2016 Twin Baron 6 fatal. While this is not strictly a fuel related crash, at 95°F OAT the accident aircraft needed 1650 feet to roll to a stop. KEZF is 2999 ft long and the aircraft first touched down 2/3 down the runway with barely 1000 feet of runway available. Two high time pilots were at the controls, and one engine ran out of fuel on the go around. KRMN, just 10NM north, has a 5000 ft runway. Why didn't they go there instead? We will never know.
 
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Big tanks give you flexibility. The standard answer is if you can fill the seats and the tanks both, your tanks aren't big enough. I can carrying 100 gallons as long as there are only two of us. If I don't fill all the tanks, I can go to gross with four passengers.
 
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