Takeoff with full fuel all the time?

[mikegreen]

So now that I've actually started flying with a purpose and somewhat of a time-frame... and spending 15 minutes filling up basically everytime I fly more than an hour... I am wondering how much fuel I should carry around?

Examples:
I73-PKB, it was about 1:10 in the air (good tailwind). The 172 I fly I see about 8gph. Full tanks when I took off (38 usable). So lets say I used 9 gallons; with 29 remaining.

The return flight later today, with the headwind, looks to be about 1:30. 12 gallons burned, with 17 remaining. The 17 should provide 2 hours of flight time, well within the 45 minute reserve I'll need this evening.

thoughts? how many folks always top off the tanks when you spend more than an hour or so in the air?

thanks,

Mike

 

[bigred177]

I can't remember the last time I took off with full tanks in the Cherokee. If I'm done for the day i'll bring the fuel back up to the tabs but that's about it. The only time I would fill it up is if I'm flying far enough to need the extra fuel and I could afford the weight. Otherwise I'll just land somewhere on my way.

Unless I can get a better price somewhere. Then I'd fill up with cheaper fuel.

 

[tonycondon]

depends on the airplane, the load, and the mission.

when Leah and I fly a 172 to visit the parents, a 3.5 hr flight, then yes we take full fuel. When I was flying with my student in the 150 it was about half tanks thanks to gross weight issues. The towplane usually starts the day out with full fuel. I have my most fun when I take off with no fuel at all, though.

 

[jesse]

If I were comfortable with the burn of the airplane and absolutely positive of the quantity of fuel and was departing VFR into great conditions I would be fine with flying 1.5 hours with 29 gallons of remaining fuel in a 172.

This is *your* life though so you need to be absolutely POSITIVE about any decision you make.

I generally add fuel as long as it's not ridiculously over priced. As Tony mentions sometimes you're better off without the fuel when there are performance concerns.

 

[murphey]

I can't remember the last time I took off with full tanks in the Cherokee. If I'm done for the day i'll bring the fuel back up to the tabs but that's about it. The only time I would fill it up is if I'm flying far enough to need the extra fuel and I could afford the weight. Otherwise I'll just land somewhere on my way.

Unless I can get a better price somewhere. Then I'd fill up with cheaper fuel.

I keep the tanks full because of the price of fuel. It's usually cheaper at home, I'm based at a field with some of the cheapest gas in Colorado. During the winter, I always fill the tanks before I put the cherokee in the hangar (unheated) to minimize water/ice issues.

Even with the XC trip a couple weeks ago, we always filled the tanks at each stop because we had no problem with weight or balance. The only time I have 4 people in the cherokee is Young Eagles - kid in front, parents in back. And by the time I'm flying with the parents (as a rule, the last few flights of the day) I don't worry about W&B because I've burned off a couple hours of fuel.

 

[gismo]

Often there's little benefit in carrying around extra fuel (tankering) and as long as adequate consideration is given to the pertinent aspects departing with less than full tanks can be as safe or safer than always filling the tanks.

I and many other pilots consider an hour's fuel at normal cruise to be an absolute minimum for both planning and execution (in flight). The only exception to that which I allow is in the daytime when the weather is good and I'm staying in the pattern at an airport with multiple non-intersecting runways (so a problem on one can't eliminate the use of all) or when there's another airport close by (like 5-10 nm distant).

For planning, I'd add to that minimum 1 hr for things like night time, adverse weather, enroute delays, terrain, and other potential issues. Another factor is how accurately you know the fuel total at departure and in the air. Worst case is a plane with inaccurate fuel gauges (like most of the GA fleet) and you don't have a clear picture of the past fuel usage. Sometimes filling the tanks is the only way to determine how much fuel you have.

Once you launch, it's vitally important to continuously monitor your fuel reserve whether you filled the tanks or not. A very large number of pilots have found the hard way that planned fuel won't keep the engine running when the actual fuel usage becomes greater than expected. In the air, you can stretch the margins to the limit (e.g. 1 hr remaining at touchdown) if you have a totalizer which gives an accurate and constant readout of the current fuel state assuming you initialized it correctly and there are no unaccounted for losses like a leaking fuel cap. It also helps a great deal if you can accurately measure your progress with GPS or at least by checking the time when passing several points along your route. But if all you have to determine the remaining fuel is the fuel gauge(s) plus a clock and book values for flow, another 10% or more of reserve fuel would be prudent.

 

[Lance F]

Lance's summary is great advice. If it's your own plane, I second the idea of a totalizer. I check the calibration on mine every month. Consistently the totalizer is within 1 or 2% of actual. With that kind of data you can fine tune your fuel load. OTOH my Mooney's full tank range is over 8 hours. Do I really need that every flight?

 

[Bob Noel]

So now that I've actually started flying with a purpose and somewhat of a time-frame... and spending 15 minutes filling up basically everytime I fly more than an hour... I am wondering how much fuel I should carry around?

Examples:
I73-PKB, it was about 1:10 in the air (good tailwind). The 172 I fly I see about 8gph. Full tanks when I took off (38 usable). So lets say I used 9 gallons; with 29 remaining.

The return flight later today, with the headwind, looks to be about 1:30. 12 gallons burned, with 17 remaining. The 17 should provide 2 hours of flight time, well within the 45 minute reserve I'll need this evening.

thoughts? how many folks always top off the tanks when you spend more than an hour or so in the air?

thanks,

Mike

Short answer: I don't always top off.

After owning my cherokee 140 a few years I was very confident
regarding the fuel burn. However, since I removed the rear
seats (to save weight), I usually don't need to worry about
exceeding the max gross of the 140.

I usually keep the tanks full just so I know the fuel configuration. In
the summer I might just bring it to the tabs, again just to know the fuel
configuration. But if the pump at the club is blocked or busy, I might
skip the post-flight refuel and fill it after the next flight.

Note that I fly out of an airport near sea level.

 

[SCCutler]

I rarely top off at my home field, but at over $6/gallon, that's understandable.

I use a totalizer, verify gas in the tanks matches what I think it should be by visual inspection, and never deviate from my minimums (which vary depending upon things like day/night, vfr/ifr, etc.).

 

[steingar]

My home drome isn't too expensive, and I always carry as much gas as I can given the load. When I see both gauges on quarters (they work, and indicate 12 gallons remaining) I'm done. If I'm not in the pattern of my destination I hit the nearest button on the GPS no matter how close I am.

I might buy it from some other dumb mistake, but I'll be damned if I'm going to run out of gas.

 

[Ted]

If I'm going to do multiple flights the same day (i.e. hour out, hour home) and I know I'll have plenty of reserve, it's fine. However if I haven't flown the plane in a while, do I really remember how much fuel got burned off and how much is remaining? So if the plane's been sitting for a bit, it's good to fill it up.

Typically I fill up when I get back to base, though, regardless. Reason being that I'm going to need the fuel anyway, might as well buy it now. Also, if you have a plane with bladders on it, keeping fuel in the plane will help keep the bladders from going bad.

In MooneyLance's case with 8 hours of fuel, I might view things a bit differently, but the longest range fuel I have is 6 hours.

 

[Palmpilot]

If you ever have an opportunity to take off from a high altitude airport, you may want to avoid doing so with more fuel than a reasonable reserve.

When I took off from a 2800-foot runway at 3600 foot altitude with a tall forest on all sides (24S), and saw how close the trees were when wind shear created a tailwind as soon as I got above treetop level, I was mighty glad that I had opted to wait for refueling until I reached a lower, longer airport with a no trees around it 25 miles away.

 

[AdamZ]

I was neurotic and topped off most place I went over an hour but thanks to my good friend and POAer Gary Shelby I've learned that its not reckless to fly with less than full tanks. As he and I figured out when you fly the same plane every or most of the time you are much more comfortable with the burn rate so I always put in enough for the flight plus reserves plus a comfortable fudge factor. That fudge factor will vary depending upon the time and distance flown, Wx, weight etc.

 

[COFlyBoy]

I fuel to the tabs. That way I have a known quantity to start with. That also give a 5 hour endurance, which exceeds my bladder endurance by at least 2 hours.

 

[steingar]

If you ever have an opportunity to take off from a high altitude airport, you may want to avoid doing so with more fuel than a reasonable reserve.

When I took off from a 2800-foot runway at 3600 foot altitude with a tall forest on all sides (24S), and saw how close the trees were when wind shear created a tailwind as soon as I got above treetop level, I was mighty glad that I had opted to wait for refueling until I reached a lower, longer airport with a no trees around it 25 miles away.

Very good point. I've mentioned (repeatedly I'm afraid) my difficulty in departing the Winwood gathering. Hair raising, though in no way dangerous. I doubt we would have made it out of there with the tanks full, though.

 

[RMCN172RG]

I don't fly with full fuel unless I need it for a long XC flight.

My normal planning mode is to have ~20 gallons, two hours, plus what I plan on using. This keeps me between 20 and 40 gallons on board.

 

[murphey]

If you ever have an opportunity to take off from a high altitude airport, you may want to avoid doing so with more fuel than a reasonable reserve.

When I took off from a 2800-foot runway at 3600 foot altitude with a tall forest on all sides (24S), and saw how close the trees were when wind shear created a tailwind as soon as I got above treetop level, I was mighty glad that I had opted to wait for refueling until I reached a lower, longer airport with a no trees around it 25 miles away.

And remember everyone has a different definition of "high altitude airport".

 

[n12365]

If I am going on a cross country trip, I always leave with the tanks topped off. If I am just staying in the local area, I just make sure I can land with at least an hour of fuel remaining.

I fly a C172 and normally only have a single passenger, so when I buy fuel, I normally fill it all the way to the top. The only time I don't do that is when I have a specific reason not to. Such as W&B, density altitude, or terrain.

Ryan

 

[Anthony]

And remember everyone has a different definition of "high altitude airport".

Ain't that the truth. Wake me up when the DA gets above 10K feet.

Local trips - fuel plus 1.0 - 1.5 hour reserve.

Cross Country - full fuel depending upon weight restraints.

 

[Fearless Tower]

Also, if you have a plane with bladders on it, keeping fuel in the plane will help keep the bladders from going bad.

This is very true - I generally try to make it a habit to keep bladder tanks topped off unless I really have an operational need to go with less fuel.

 

[Ted]

Ain't that the truth. Wake me up when the DA gets above 10K feet.

Also depends on what you fly and the strip you fly out of. Flying the Aztec out of a 4000 ft strip at 4500 MSL and 8500 DA was definitely fun. Not difficult, but different.

 

[dmccormack]

I own and fly a low-powered airplane (65 hp) when I'm not flying someone else's Cessna or Beech.

I rarely top off the header tank for several reasons:

• 3 hours in the Chief would be murder
• I don't like the smell of gas when it sloshes through the cap seal onto the boot cowl
• A gallon of Avgas weighs 6 lbs. 4 gallons less than full is 24 lbs I don't have to lift.
• On a hot, humid day it can take a while to climb above the trees and hills that infest all our local airports
• It's inconsiderate to stop, put in 3 gallons, tie down, prop, untie, and get in while the guy in a Barron is waiting
• I burn 3.5 GPH

A couple of weeks ago I returned from Windwood with about 40 minutes fuel left in the tank when I landed. I didn't look like alot, and is definitely my bottom limit.

 

[COFlyBoy]

And remember everyone has a different definition of "high altitude airport".

Agreed. I don't consider anything below 7000 MSL as high altitude. Leaning for max power in the runup is a habit.

OTOH, I may have a very different view of what constitutes a "short" runway. I don't like thinking about taking off from anything under 3000 feet long.

 

[nyoung]

In the winter, I always top. Summer, I go to tabs.

With my typical passenger configuration (wife, 2 little kids) overgross concerns don't come into play - but the lighter load in the summer is noticeable with takeoff roll and climbrate. Performance is good enough in the winter that I don't care about the extra weight.

I'm also fortunate to base at an airport that has (close to, if not) the cheapest fuel around. Therefore, it generally makes sense to tanker fuel to wherever I'm going. If my homebase fuel prices were $6.00, I might plan differently.

 

[poadeleted20]

1. Altitude above me.
2. Runway me.
3. Fuel in the fuel truck.

What do these all have in common? They are the most useless things in flying. Therefore, unless I have a good reason for taking off with less than full fuel (like needing to eliminate the extra fuel weight for payload or performance), I top 'em off each time.

Yeah, that's kind of conservative, but once you've landed with nine minutes of fuel left in the plane (NAS Fallon, May, 1974 - "Beck! Levy! Det OinC wants you in his office -- NOW!), you really get to thinking that flying with less fuel than you can just ain't worth whatever convenience accrues therefrom. It's also a nice way of saying "thank you" to the FBO who provided the nice place to park and the nice room with the nice computer for flight planning and weather.

 

[taters]

I second the idea of a totalizer.

I third it. Love the Shadin . Scary accurate hard to live without.

 

[PittsDriver]

I agree with everything Ron said but you can take it to extreme. My Columbia 400 I would always park it with the fuel at the tabs in case I had to haul some hefty passengers around. I like an hour or so of reserve on a good VFR day and more on a hard IMC flight because my fuel gauge is my Optionometer. But if I know I'm going only a couple of hours away, why haul all that extra gas that's just going to slow me down and cause me to burn more of it to do the same trip? Besides, then I can go ahead then and buy gas the the FBO visited before I return home.

 

[dmccormack]

Full fuel is a downright waste in some airplanes -- it starts pouring out the vent as soon as you top off.

Top off, to the tabs, totalizers -- whatever, but, I'm convinced there would be far fewer fuel exhaustion incidents if folks would take the time to look in the tanks (dip them if you can't actually see).

If I check the tanks, I calculate the time remaining based on the gallons and that's all that matters, period.

Gauges and gadgets are nice but goodness gracious there's nothing that beats a look inside and a confirmation of what you actually have.

 

[Gmaper]

Also depends on what you fly and the strip you fly out of. Flying the Aztec out of a 4000 ft strip at 4500 MSL and 8500 DA was definitely fun. Not difficult, but different.

Ted, my Aztec time was always near sea level operating in Florida. 144 gallons was never uncomfortable. Any qualms about that at 8500 DA? Say if the LE quit at about 200 or 300 feet?

 

[timrj]

My grumman holds 52 gallons. That is a lot of fuel. I generally just fill to the tabs (about 38 gallons). No reason to carry all that extra weight around. I have a JPI 700 and fuel flow and used is easy to see. My bladder would give out before I would use up 38 gallons and 4 hours in a small plane is murder on the rest of my body as well.

Flights with IMC take different planning but I don't make too many of those. For those I load up as much as I can.

 

[Ghery]

Our club rules require us to put the planes away with full tanks. So, I always plan on starting from the home drome with full fuel. Will I refuel somewhere else? It depends on how long I flew to get there. Anywhere on the west side of the state? Probably not. Over to the central part? Probably not. Over to the east side? Yup, I'll want full tanks before I leave. Know your fuel burn, know how much you started out with, know how long you'll be in the air and what you feel is a good reserve. I don't worry about the 172N. It has long range tanks (50 gal) and at 8.3 gph that's 6 hours worth of gas. I don't have a 6 hour bladder, so I'll be on the ground long before it becomes an issue. Could it make it from OLM to PUW and back without refueling? Yes. Will it? Not with me on board. The Arrow (48 gal and a higher fuel burn) isn't going to do the round trip, especially if I detour and go through the Columbia River gorge due to clouds over the Cascades. Not enough range. The 182? I haven't really pushed it. I gas up at PUW. Full tanks to go over, full tanks to come back. It goes back to the underlined text above. If the engine goes silent, I want it to be for a reason I can't control. I can prevent replacing all the fuel with air.

 

[Ted]

I third it. Love the Shadin . Scary accurate hard to live without.

I realize that you're intentionally overstating a bit, but all these new tools are nice to haves that are definitely not hard to live without. While I'd never discourage getting them or using them, it's really very easy to live without them. I opted not to bother getting the fuel flow additions when I had my engine monitors installed because it wasn't worth the extra money.

Ted, my Aztec time was always near sea level operating in Florida. 144 gallons was never uncomfortable. Any qualms about that at 8500 DA? Say if the LE quit at about 200 or 300 feet?

I think it would depend on how much load you had in otherwise. The 8500 DA takeoff I did was with partial fuel and two people, otherwise empty. So if an engine quit we actually probably would have been able to make it back to the airport given the surrounding terrain. If we had full fuel and a full plane, It would be much less comfortable if the engine quit at a bad time. The next morning we left with full fuel, three people, and luggage. DA was probably down to about 6500 ft and it was probably about as comfortable as the previous day.

In the eastern half of the country where I do about 99% of my flying, it's never an issue, much like with you in Florida.

 

[gismo]

I realize that you're intentionally overstating a bit, but all these new tools are nice to haves that are definitely not hard to live without. While I'd never discourage getting them or using them, it's really very easy to live without them. I opted not to bother getting the fuel flow additions when I had my engine monitors installed because it wasn't worth the extra money.



I think it would depend on how much load you had in otherwise. The 8500 DA takeoff I did was with partial fuel and two people, otherwise empty. So if an engine quit we actually probably would have been able to make it back to the airport given the surrounding terrain. If we had full fuel and a full plane, It would be much less comfortable if the engine quit at a bad time. The next morning we left with full fuel, three people, and luggage. DA was probably down to about 6500 ft and it was probably about as comfortable as the previous day.

In the eastern half of the country where I do about 99% of my flying, it's never an issue, much like with you in Florida.

Ted, I wouldn't discount the value of a good totalizer without living with one for a while. With fuel flow gauges (typically fuel pressure gauges that read proportionally to flow) you can estimate fuel used pretty accurately if you fly a typical profile (take off, climb, cruise, descend, land) but when the day comes you end up changing altitude and power several times to avoid ice then end up popsicled anyway with the power way up to stay in the air, you will wish you had a more accurate accounting of the fuel left in your tanks. That said, if you're willing and able to allow an extra padding of the fuel reserves the exceeds the error margins of your usage estimations then the totalizer is indeed superfluous. It's real advantage is allowing you to minimize that fuel padding to the conditions.

 

[Palmpilot]

And remember everyone has a different definition of "high altitude airport".

3600 foot elevation with a long runway and a benign obstacle environment wouldn't worry me much. It was the combination of that elevation with a 2800 foot runway length and tall forest on all sides that led me to spend the night before going over the takeoff performance tables. (This was in a Cessna 172, by the way.)

It was hitting the wind shear and having to force myself to lower the nose to maintain airspeed in spite of not being much above the tops of the trees that made me glad to be 100 pounds under gross.

The list of obstacles on Skyvector.com is an eye-opener:

Obstacles:88 ft Trees 960 ft from runway
+40 FT TREES 10 FT FROM RY END, 105 FT L.
65 ft Trees 801 ft from runway, 100 ft right of center
PILES OF ROCKS AND +10 FT TREES FM RY END TO 200 FT 65 FT R OF CNTRLN.

http://skyvector.com/airport/24S/Pinehurst-State-Airport

 

[flyingcheesehead]

Agreed. I don't consider anything below 7000 MSL as high altitude. Leaning for max power in the runup is a habit.

OTOH, I may have a very different view of what constitutes a "short" runway. I don't like thinking about taking off from anything under 3000 feet long.

Come play down here in the thick air, and you'll see the other side of the coin!

I've been in and out of a 1,000-foot grass strip. I've also had the same airplane at Leadville on a 12,200 DA day, and left 2,000 feet of pavement behind me, going downhill. It's amazing what DA does to your performance!

 

[Ted]

Ted, I wouldn't discount the value of a good totalizer without living with one for a while. With fuel flow gauges (typically fuel pressure gauges that read proportionally to flow) you can estimate fuel used pretty accurately if you fly a typical profile (take off, climb, cruise, descend, land) but when the day comes you end up changing altitude and power several times to avoid ice then end up popsicled anyway with the power way up to stay in the air, you will wish you had a more accurate accounting of the fuel left in your tanks. That said, if you're willing and able to allow an extra padding of the fuel reserves the exceeds the error margins of your usage estimations then the totalizer is indeed superfluous. It's real advantage is allowing you to minimize that fuel padding to the conditions.

It doens't just have to be that you've changed altitude several times to avoid ice and then still ended up with more power in to stay in the air. You can also easily enough have storms and other such things that you need to divert around and add a good sum of time to your route, have headwinds worse than forecast, etc.

In any case, I've had all of them happen to me, just as you have. If you know your plane and have reasonable reserves, I maintain that this is fine. I didn't say that it's useless, but just like any other tool, I get wary when people make statements like "Hard to live without." As a full believer in the value of GPS and engine monitors I do see value in fuel totalizers, but I can also live just fine without any of them.

 

[wabower]

:wink2:

It doens't just have to be that you've changed altitude several times to avoid ice and then still ended up with more power in to stay in the air. You can also easily enough have storms and other such things that you need to divert around and add a good sum of time to your route, have headwinds worse than forecast, etc.

In any case, I've had all of them happen to me, just as you have. If you know your plane and have reasonable reserves, I maintain that this is fine. I didn't say that it's useless, but just like any other tool, I get wary when people make statements like "Hard to live without." As a full believer in the value of GPS and engine monitors I do see value in fuel totalizers, but I can also live just fine without any of them.

Although possibly not quite as long?:wink2:

 

[airguy]

Come play down here in the thick air, and you'll see the other side of the coin!

I've been in and out of a 1,000-foot grass strip. I've also had the same airplane at Leadville on a 12,200 DA day, and left 2,000 feet of pavement behind me, going downhill. It's amazing what DA does to your performance!

Yup - I remember back in my student days, I had an instructor demonstrate to me a max-gross weight takeoff in a 172 out of Durango, CO at about 80 degrees OAT. We easily burned 4000' of runway (9000' total length IIRC) and struggled to climb out at about 150'/min to the south, waiting for the terrain to drop out from under us.

It was shortly after that point that I realized my primary instructor was an idiot and I was relatively lucky to have survived my PPL training.

 

[gismo]

It doens't just have to be that you've changed altitude several times to avoid ice and then still ended up with more power in to stay in the air. You can also easily enough have storms and other such things that you need to divert around and add a good sum of time to your route, have headwinds worse than forecast, etc.

In any case, I've had all of them happen to me, just as you have. If you know your plane and have reasonable reserves, I maintain that this is fine. I didn't say that it's useless, but just like any other tool, I get wary when people make statements like "Hard to live without." As a full believer in the value of GPS and engine monitors I do see value in fuel totalizers, but I can also live just fine without any of them.

Well I would put the priority of a totalizer below onboard weather and well below GPS but I can see how once you're used to having it living without would seem traumatic. But the real bottom line is having one lets you be comfortable with smaller reserves because you have a much more accurate idea what your actual reserves are.

 

[Ted]

Although possibly not quite as long?:wink2:

Hey, I got out of bed this morning and a toilet didn't fall on my head, so I figured it was a good day.

Well I would put the priority of a totalizer below onboard weather and well below GPS but I can see how once you're used to having it living without would seem traumatic. But the real bottom line is having one lets you be comfortable with smaller reserves because you have a much more accurate idea what your actual reserves are.

I don't dispute the fact that it can be a good aid to helping you have a more accurate idea of how much fuel you have and whether or not you need to land sooner rather than later. As you know I'm a fan of having tools, but I think it's very important for people to be able to survive without those tools in flying.

About half of my flying has been with XM, on-board radar, and an engine monitor. About half has been without. I don't panic and the loss of any of those items, but I do change according to what those tools offered me.