Gas to go the distance?

December 18, 2008 by Bruce Landsberg

Why do pilots run out of fuel? We can all count the ways and unlike in cars, where it is merely an inconvenience, we are almost guaranteed significant damage and occasionally, fatalities.

Despite our disdain for the humble fuel gauges on aircraft they tend to be pretty accurate toward “empty”. Measuring time in your tank rather than distance and allowing the ASF golden hour of reserve will pretty much guarantee that you won’t fall victim to this foolishness.

There is good news, however. Several years ago ASF embarked on a fuel awareness campaign in several venues including a live seminar, a Safety Advisor Fuel Awareness and our acclaimed Pilot Safety Announcements (PSAs) that have been widely distributed. To date,there have been over 41,000 views but that’s still only 10% of AOPA’s membership – please send the links to a friend.

Would You Fly This Airline?

Hybrid Power

When we created the PSAs, three accidents a week were occurring. As of last year, we are now down to 1.7 per week, a 42% decrease. Are there other factors? Absolutely! The Technologically Advanced Aircraft do a great job of reminding pilots, not too subtly sometimes, that they’re about to do something really stupid. This may be a range ring on an MFD, a flashing annunciator or perhaps a datalink message to your insurance company (just kidding on that last one). Flying hours also play a significant part, so it’s not time to declare victory yet.

Despite the success, 2007 still had 90 fuel mismanagement accidents and I know we can do better. Look for a new effort next spring as ASF calls on you to help us further reduce this most unnecessary of accidents.

Bruce Landsberg
Senior Safety Advisor, Air Safety Institute

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  • Jim McCord

    Bruce –
    I’m glad to see that fuel accidents are down, and I expect ASF’s (and other’s) efforts are having an impact. There is still work to be done, as you indicate, to reduce the number further. While preparing for a local FAASTeam workshop I dug up several local fuel accidents. Sadly, there are plenty to choose from! What surprised me were the pilots that relied on the fuel gauges: some pilots seem to need a reminder that the fuel gauge is the most inaccurate indicator in the cockpit, exept near ‘E’. I expect most CFI’s stress this, but it needs reinforcement (at every Flight Review). The other observation was pilots that took off with minimal fuel, intending to go only a short distance. While they might have had a legal reserve (5 min flight and 35 min of fuel) because of how the fuel was distributed they experienced unporting or a fuel starvation incident. Although most folks survived these accidents, the costs are still too high for GA.

  • Dennis Thornton


    I have been flying since the mid 1960’s and now fly sport pilot in my own 1946 Champ with an O-200A conversion, 13 gallon tanks in each wing and a very complete panel with Mode C. The airplane is based in a hanger in my back yard on a private 2000 foot grass strip in northern Indiana.

    I have never trusted fuel gauges so I keep a log in my airpane with the date, fuel used, tach time and rate of fuel burn between each and every fillup. Knowing the typical fuel burn allows me to keep a comfortable cushion in the tanks. I try to never get much past one hour remaining before refueling. I also log oil changes and oil added between changes the same way so if something starts to go wrong in the engine and oil consumption or fuel burn starts to go up I might catch it before anything bad happens in the air.

    My method may not be practical for those renting airplanes but for those in flying clubs or owning their own airplanes it takes very little effort to add these simple steps to assure the safety of themselves and their passengers.

  • Neil Ulman

    I’m fortunate to have a Garmin GNS 430W GPS installed in my Cessna 172M. Having entered the fuel flow (8.1 gph at cruise power) into the Garmin, I visually inspect or stick the tanks at each pre-flight inspection, then enter the start-up fuel-on-board (FOB) into the Garmin. It automatically keps track of the engine time and continually calculates fuel remaining (FOB), saving me the need to do mid-air, mental (and possibly fallible?) math. Like Mr. Thornton, I also maintain logs in order to keep checking my estimated fuel flow against reality. I assume most GPS’s have similar fuel monitoring capability. My Garmin is is only doing the math, of course, not physically monitoring fuel levels. But I consider it more reliable than my fuel gauges against which I check its calculations. It’s very easy to use and I highly recommend it.

  • Lee Powell

    I have owned this 1969 C-180 since 1975 and I can tell you that the float type gauges are not too reliable except when one-quarter full. Solution is a stop watch or chronometer in the instrument panel. I reset to 00:00 when I fuel the aircraft and start the clock while taxiing to active. I stop the clock at shutdown. I continue this until the next time I fuel and then start at 00:00 again. By keeping the time of fuel burn on the clock I know the consumption even if it is over a few days of short flights. I’m comfortable with a reserve of 1.5 hours. I can carry 84 gallons or 7 hours, my body is good for 3.5 hours.

    Another trick I use for preflight is my gauging stick. The last time the fuel cells were drained I marked a stick at 5 gallon intervals as I refilled the fuel cell. I transferred these readings to a piece of 1/8″ X 1-1/2 flat bar aluminum, marked in gallons, and painted the reverse side flat black to it is easy to read in bright sunlight. Drilled a 1/4″ hole in the top end and fastened a 3′ long piece of cord to the stick, that way if I drop it I can retrieve it from the fuel cell. As long as I am on level ground this gauge stick is very accurate and correspondes to the expected fuel burn.

    Thats my two bits worth.

  • Bruce

    Excellent practices. Unfortunately, the folks prone to running out of gas are not so diligent and we need to figure out a way to “encourage” them to employ the same smarts. Many Thanks for the comments.

  • Cary Alburn

    I’ve “run short” a couple of times in the long distance past, in my younger and more foolish days. On one occasion, I filled the 78 gallon tanks of our first 182 with 77 gallons and on another occasion I ran out one of the tanks of our T210 and had a hard time restarting on the remaining tank, although it showed 1/4 full.

    Now I “stick” the tanks before every flight, using a commercial fuel stick that happens to be really accurate for my Cessna P172D, although actually designed for newer 172s with long range tanks (52 gals). I also have an EI fuel flow meter, which is amazingly accurate, which I have set to warn me each 5 gallons and to act as if I’m about out at 42 gallons used (the owners manual claims that there are 5 unusable in each tank–not true from empirical experience, but I “assume” that for purposes of flight planning). My 180hp Lyc 360 burns just under 10 gph at cruise, which makes quicky calculations easy, but the fuel flow meter gives me a more accurate total.

    3.5 hours is just about my personal physiological limit, and that leaves a safe fuel reserve except in those situations in which a 45 minute reserve is required (IFR, night) or advisable. Even then, knowing that the so-called “unusable” is not true other than perhaps an unporting issue that might happen in an uncoordinated turn, I feel pretty comfortable running to 3.5 hours or even a tenth or two beyond. More than that, and I would rather stop for fuel than take the chance.


  • http://AOPA Buz Allen

    Having been a KC-135 USAF Pilot during SEA I personnally witnessed two aircraft go down because the pilots flying them waited til almost tanks dry to head for the tanker. Easy to understand when dodging missiles and post-strike euphoria that you are still alive !! Impossible for me to comprehend any pilot on a civilian flight not planning or realizing how precarious a situation they create when mis-managing their fuel !! How many times have I thanked the Good Lord for the experiences I’ve Had and Always been saved by a little EXTRA Fuel. I’m a Corp. pilot now and I don’t hesitate one bit to tell the boss we’ll have to stop along the way for fuel even when I’ve planned a 1hour reserve. It’s a No-Brainer compared to the Night-mare of trying to convince a Non-pilot Judge and group of Lawyers why you Thought You could Make-It!! Stupid Should Be Painfull and it usually IS !!! Don’t Be A Dummy!! Carry EXTRA Fuel !!!