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What is your fuel minimum?


201er

Fuel Minimum  

78 members have voted

  1. 1. What is the absolute minimum amount of fuel you will take off with?

    • 0-5 gallons
      0
    • 5-10 gallons
      5
    • 10-15 gallons
      25
    • 15-20 gallons
      9
    • 20-25 gallons
      13
    • 25-30 gallons
      13
    • 30-35 gallons
      4
    • 35-40 gallons
      3
    • 40-45 gallons
      3
    • 45+ gallons
      3


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5 hours ago, Raptor05121 said:

My stick is accurate as hell. I'd say within 0.1gallon but I made a "cheat sheet" on my POH in my plane with level readings and I put "accurate to 0.2 US Gal" in case someone else took it up

 

I stick the tanks but with the totalizer is always within 1/4 gallon of the totalizer. 

 

-Robert

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My magic number is 10. If I ever reach a destination with anything under 10 gallons fuel on board I will refuse to land! I just wont do it! :D 

On a more serious note Yogi Berra said "when you come to a fork in the road, take it." My airplane having two tanks is sort of like a fork in the road! So I fill them! I figure both were meant to carry fuel...not air!

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As we all know VFR fuel reserves are 30 minutes day and 45 minutes night @normal cruise.  Typically I want an hours reserve after I land and always assume an hour flight even if it is just around the pattern. At a conservative 15 GPH I would have 30 gals of useable on takeoff. Interestingly In my A/C I see empty tanks with 15 gals useable per side so no ability to use a dip stick. 

As a heads up here is a dip stick story. I recently flew in a helicopter and was concerned about the fuel on board as the pilot had been giving rides to friends at the local airport.  I requested the pilot dip stick the fuel before climbing aboard which he did. I watched from the side as the rotor was still turning. He said it was OK but I did not trust the statement as I had been timing  the flights. We agreeded he would hover taxi to the fuel pumps a foot or so off the tarmac. Once we reached the fuel area he inadvertently rose to about four feet and at that moment the helo ran out of fuel. He was unable to recover and we landed very hard on the right skid. The Main rotor just missed the tarmac as it tipped on its right side where I was sitting. Luckily it bounced to center and except for a very hard landing we walked away unscathed.  

When we reviewed the issues I asked about the dip stick which I could not see from outside the rotor area. He showed me the stick. What he saw was the years of fuel stain on the stick as opposed to actual wet fuel on the stick. He had intended to fly at 60 feet to the pumps which were at the other side of the airport. Thankfully we did not. Flying is not inherently dangerous but it is terribly unforgiving. I consider myself lucky in this instance and it reinforces the fact that you cannot be to careful regardless of what others may say. Trust your own judgement. Fly safe.

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25 minutes ago, Cris said:

As we all know VFR fuel reserves are 30 minutes day and 45 minutes night @normal cruise.  Typically I want an hours reserve after I land and always assume an hour flight even if it is just around the pattern. At a conservative 15 GPH I would have 30 gals of useable on takeoff. 

I do something similar. I plan for an hour reserve based on the worst book cruise fuel burn. 

Can't really answer the poll since I think in terms of time not gallons and different aircraft have different burn rates.

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17 minutes ago, midlifeflyer said:

Can't really answer the poll since I think in terms of time not gallons and different aircraft have different burn rates.

There's a reason the poll is in gallons and not minutes of fuel. When you get that low, for many of us it's about the physical amount of fuel that is minimum and not even about how long it will carry you.

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I agree this poll is inconclusive due to different burn rates depending on aircraft. But endurance time is most meaningful during cruise. During t/o and climb the fuel flow rate will be twice or more than that of cruise and the endurance will show to be half of actually available at cruise. In a power reduction descent the endurance time will show as more than actual at cruise.

What I do is I use both pieces of information. Endurance time and raw gallons remaining.

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16 hours ago, gsxrpilot said:

A stick was the only fuel gauge I ever used with my C.

I don't pay a lot of attention to the fuel gauges in my plane. They like to stick so I have to tap them with a knuckle to get them to move, and they aren't very accurate either when they do move. I stick the tanks prior to every flight, make a note of what is in each tank, and then note the time that I am on each tank. I don't have a fuel totalizer or fuel flow meter so I plan for 11 gal/hr even though I know I am going to be burning less than that. It's just a little cushion.

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16 hours ago, Raptor05121 said:

My stick is accurate as hell. I'd say within 0.1gallon but I made a "cheat sheet" on my POH in my plane with level readings and I put "accurate to 0.2 US Gal" in case someone else took it up

 

How did you actually calibrate your stick ?  How do you make sure the stick is perfectly vertical and stuck in the same place or does that not really matter so much ?

Edited by epsalant
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Just now, epsalant said:

How did you actually calibrate your stick ?  How do you make sure the stick is perfectly vertical and stuck in the same place or does that not really matter so much ?

I was using a free paint stirrer from Home Depot for awhile, but broke down and bought one of the Fuelhawk Universal Guages for $16.50. (Hopefully I won't have my CB Membership card revoked for that, but it is one of the hazards of having to drive past Aircraft Spruce every time I go to the airport...) I always put it straight down as close to the center of the cap opening and figure I am getting close enough to the same place each time.

It has a method of calibrating it where you don't have to start with an empty tank, you could do the same thing with a regular stick. Preferably you want very little fuel in the tank, just enough to touch the bottom of the stick. Mark where it is on the stick, then add some fuel. They say add 5 gallons and mark again, some people add 1 gallon at a time and mark it, I did 2 gallons and marked each one down. When you have it full (my tanks hold 26 gallons) then it's simple math going backwards to find out what your starting fuel level was and each mark in between.

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There have been a lot of comments regarding a little fuel in one tank or very little in two tanks.  Although there have been one or two accidents resulting from air being sucked in, the vast majority of fuel-related accidents are either mis-management (e.g. fuel in right tank, none in left tank, selector on "Left") or fuel starvation (no fuel left tank, no fuel right tank).

If possible, never be low in either tank.  If you find yourself low on fuel, it's more important to realize that you are low on fuel than to worry about whether it's in one tank or  both.  If you are low on fuel and it's in both tanks then you should be spring-loaded to switch tanks with any indication of sputtering (or worse) and not get so high on final that you have to do an extended side-slip.  If it's all in one tank, than make sure you know which tank it's it and make sure you don't hit the fuel selector unless your engine stops !

Low fuel is probably responsible for a lot of accidents in which it is not listed as a causal factor.  E.g. focusing on fuel may make one forget the gear or avoid a go-around when a go-around is really in order.  I know I don't fly as well when I'm worried about something, I don't think most people do.

Personal opinion:  you should be worried with less than one hour of fuel on board.

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2 minutes ago, Skates97 said:

I was using a free paint stirrer from Home Depot for awhile, but broke down and bought one of the Fuelhawk Universal Guages for $16.50. (Hopefully I won't have my CB Membership card revoked for that, but it is one of the hazards of having to drive past Aircraft Spruce every time I go to the airport...) I always put it straight down as close to the center of the cap opening and figure I am getting close enough to the same place each time.

It has a method of calibrating it where you don't have to start with an empty tank, you could do the same thing with a regular stick. Preferably you want very little fuel in the tank, just enough to touch the bottom of the stick. Mark where it is on the stick, then add some fuel. They say add 5 gallons and mark again, some people add 1 gallon at a time and mark it, I did 2 gallons and marked each one down. When you have it full (my tanks hold 26 gallons) then it's simple math going backwards to find out what your starting fuel level was and each mark in between.

Thanks.

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5 hours ago, PTK said:

My magic number is 10. If I ever reach a destination with anything under 10 gallons fuel on board I will refuse to land! I just wont do it! :D 

On a more serious note Yogi Berra said "when you come to a fork in the road, take it." My airplane having two tanks is sort of like a fork in the road! So I fill them! I figure they were meant to carry fuel...not air!

surprised nobody said anything about that!!

if i land with less than 10 gallons,,, i will refuse to take off!!

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I don't have a fixed reserve in gallons or time.  I start with the 45 minutes IFR minimum.  

To that I add a reserve factor based on arrival and departure delay possibility. 

For example, coming into Chicago or D.C. areas I can count on ATC assigning lower altitudes than I want far from my destination.  If weather is low enough that no visual approaches are in use I expect vectors to here, out there and every which way, except direct. 

Heading for a major metro area airport in general IMC I want to have 2+ hours fuel aboard at my scheduled landing time. 

Compare that going into Rawlings WY where 45 minutes reserve may be plenty even in IMC. 

Enroute diversions due to weather have added 50% to some of my recent X-C trips: A planned two hour leg took 3 hours.  Nice to have that fuel in the tanks.

Don't forget the fuel has to be there to take you to your alternate, too, even if you don't divert.  

I recall the old aviation saying, "the only time I have too much fuel aboard is if the airplane is on fire."

 

 

 

 

 

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Long Body weirdness... (Thanks for the reminder, Cris)

The placement of the fuel caps must be farther out on the wing than the other M20s.

Looking in the tank may reveal a dry bottom of the tank.

Sticking this tank, the stick will read zero.  A short while before the usable fuel is used.

The LBs got the wing mounted mechanical fuel gauges, calibrated for ground reading, to help with this situation...

Looking in the tank and not seeing fuel, leads me to fill 15 gallons per side.  Hence the one hour per side.

A quick flight around the pattern, is often a flight out to a nearby VOR and back.

For reference, the LBs have about 50gal. Per side... unless the additional quantity has been added...

Best regards,

-a-

Edited by carusoam
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32 minutes ago, Jerry 5TJ said:

I don't have a fixed reserve in gallons or time.  I start with the 45 minutes IFR minimum. 

I just want to point out that this discussion is not asking "what are your fuel reserves." I'm sure that's been discussed or warrants another discussion. This is a question of what is the absolute lowest number of gallons you could ever imagine yourself taking off with (regardless of how long that will last). You fly an R. Burns what, about 30gph on takeoff, 15 in cruse? 7.5 gallons should be legal VFR reserve. 2.5 gallons should be enough to get it around a pattern in 5 minutes. 10 gallons is legal. Will you takeoff with 10 gallons? If not, how many gallons of fuel is the minimum you've gotta have in your tanks before you would venture to takeoff and fly extremely close? When you get this low, I think most guys are going to be more worried about where the fuel is, how much is unusable, how much is your measurement error, are your fuel tanks seeping any, how much fuel does it take not to risk unporting the pick up, etc than about how many minutes it is good for.

Edited by 201er
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Best way to calibrate your stick is to dip the tanks before every fill up, note the level, how many gal added, a little math, and note the fuel remaining on the stick. The more you fly, the more marks you get on the stick and pretty soon you have a well calibrated fuel stick.

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1 hour ago, Skates97 said:

It has a method of calibrating it where you don't have to start with an empty tank, you could do the same thing with a regular stick. Preferably you want very little fuel in the tank, just enough to touch the bottom of the stick. Mark where it is on the stick, then add some fuel. They say add 5 gallons and mark again, some people add 1 gallon at a time and mark it, I did 2 gallons and marked each one down. When you have it full (my tanks hold 26 gallons) then it's simple math going backwards to find out what your starting fuel level was and each mark in between.

Maybe a C is different from my F.  I dip also, but the markings I did by testing are non-linear due to the dihedral of the wings/tanks.  Also, my tanks are at 10 gals when the fuel is just lapping directly below the filler.  To make sure that the 10 gals were indeed usable, I ran each tank dry (separate occasions for smartass comments) and then filled to directly below the filler to verify.

I'd takeoff on 10 gals if I knew that it was all in one tank.  If I can't dip a tank, I assume it's empty.  I guess it's an academic question because I'd only do it for a single circuit which would be pointless really.

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13 minutes ago, 201er said:

You fly an R. Burns what, about 30gph on takeoff, 15 in cruse? 7.5 gallons should be legal VFR reserve. 2.5 gallons should be enough to get it around a pattern in 5 minutes. 10 gallons is legal. Will you takeoff with 10 gallons? If not, how many gallons of fuel is the minimum you've gotta have in your tanks before you would venture to takeoff and fly extremely close? When you get this low, I think most guys are going to be more worried about where the fuel is, how much is unusable, how much is your measurement error, are your fuel tanks seeping any, how much fuel does it take not to risk unporting the pick up, etc than about how many minutes it is good for.

For flying around for fun or a local fuel run i normally climb to 3-4K. So for that mission it includes 5 mins taxi / warm up, 3 mins for takeoff and climb, and puts around at LOP cruise.  I'm guessing the actual fuel burn difference between the J and R for that mission will be very little. Even when I'm going on a trip I normally switch over to LOP cruise climb in the 4K area. 

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11 minutes ago, Cyril Gibb said:

Maybe a C is different from my F.  I dip also, but the markings I did by testing are non-linear due to the dihedral of the wings/tanks.  Also, my tanks are at 10 gals when the fuel is just lapping directly below the filler.  To make sure that the 10 gals were indeed usable, I ran each tank dry (separate occasions for smartass comments) and then filled to directly below the filler to verify.

I'd takeoff on 10 gals if I knew that it was all in one tank.  If I can't dip a tank, I assume it's empty.  I guess it's an academic question because I'd only do it for a single circuit which would be pointless really.

No, the C is non-linear as well. That is why I would add 2 gallons and mark, and another 2 and mark, etc... The level between 10-12 gallons is much different than the level between 20-22 gallons. The fuel stick that came with my plane was marked off at exact intervals, needless to say it was not very accurate.

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5 hours ago, 201er said:

I just want to point out that this discussion is not asking "what are your fuel reserves." I'm sure that's been discussed or warrants another discussion. This is a question of what is the absolute lowest number of gallons you could ever imagine yourself taking off with (regardless of how long that will last). You fly an R. Burns what, about 30gph on takeoff, 15 in cruse? 7.5 gallons should be legal VFR reserve. 2.5 gallons should be enough to get it around a pattern in 5 minutes. 10 gallons is legal. Will you takeoff with 10 gallons? If not, how many gallons of fuel is the minimum you've gotta have in your tanks before you would venture to takeoff and fly extremely close? When you get this low, I think most guys are going to be more worried about where the fuel is, how much is unusable, how much is your measurement error, are your fuel tanks seeping any, how much fuel does it take not to risk unporting the pick up, etc than about how many minutes it is good for.

Again, I don't have a minimum for takeoff.  I have a minimum for landing.  That plus my planned burn determines my minimum takeoff fuel.

If I was flying from S50 to PLU (about 15 miles) and I planned to stay at 1500', I would plan on 3 gallons of burn so I would want a minimum of 13 gallons if all the fuel is in one tank. However, if it is split evenly between the wings I would want at least 8 gallons (because of the caution in my POH) in the tank I want to use for takeoff and 8 in the tank I want to land with, so my new minimum would be 16 at takeoff, or 17 at start.  If I'm flying 600 NM (S50 - KSQL), I want to land with 10 and I need 1 for engine warmup, 2 for the climb, and 36 for cruise (no wind).  That means my minimum would be 49 gallons.  I'd fill to the 50 gallon tabs.

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I've been watching this thread with interest.  My F has bladders in it and is placarded for 25 a side.  I ran down my right tank to where the float was on the bottom of the tank and there was still 9ish gallons in the tank when I refueled.  From what I have read there isn't a way to accurately stick the bladder tanks.  How do others with bladders know how much fuel is in there?  The gauges suck so I have been doing it on time and estimated burn.  

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