After 31 years as a flight instructor and considerably longer as a certified pilot, I’ve seen my fair share of accidents and incidents caused by aircraft running perilously low on fuel. In the latest data (2012) listed on the NTSB.gov website out of 988 general aviation accidents (personal flight), some 50 were attributed to fuel (or lack thereof). It is impossible to tell how many out-of-fuel incidents actually happened that year, or any year, in general aviation, because most pilots who get away with landing the airplane on an airfield after losing power never mention it to the FAA. (Would you?) The good news is that the graph lists no fatalities attributed to such accidents in 2012; but going back a decade from there not all pilots were so lucky.
I have to say, I work hard so as not to be one of those pilots. In my career I’ve flown plenty of airplanes with fuel gauges placarded “INOP” or with gauges so clearly inaccurate that one just knew not to trust them. I was brought up in aviation to visually inspect, and even measure (with a calibrated dipstick) the fuel in my tanks, and to use a calibrated time/distance method of tracking my fuel burn in flight. So, yeah, I’ve got a lot of tools on my checklist to prevent me from running out of fuel on a flight. So do a lot of other pilots I know.
Then why do they still run out of fuel? There are a few out-of-fuel accidents caused by shrinkage of the fuel tank bladder from age (even though senders registered it full, and visual inspection showed it full, the bladder could not hold as much fuel as indicated). Those are, however, rare. And even in those cases I’d question the pilot, wondering why he didn’t notice that the tanks didn’t seem to hold as much as they used to hold. There are a few out-of-fuel incidents from leakages (a stuck gascolator quick drain, for instance). Again, I’d question the pilot on his/her preflight thoroughness (always step back and look at the airplane top to bottom one more time before you climb in to fly away).
Then there are the math errors and buttonology errors. Essentially the pilot miscalculates actual fuel burn, and, knowing his fuel gauges are generally inaccurate s/he ignores them until the engine starts to sputter. This problem can occur if the pilot forgot to consider his fuel burn on climb, in a full-rich mixture configuration. Or, he may have completely forgotten to lean the mixture.
Buttonology errors are more of a modern airplane’s problem. Perhaps the pilot did visually inspect his tanks and noted that each seemed to be down a few gallons. But it is tricky with some fuel totalizers to program in the exact amount of fuel in each tank. Maybe the pilot just taps the “full” button but promises she’ll remember the tanks aren’t full. And then the headwinds are stronger than predicted at altitude. Yet her fuel totalizer tells her not to worry—she’s got enough gas to get to her destination. Except she doesn’t.
Another pilot just pushed the throttle up, figuring he could go faster into the headwind and solve the problem that way. He did not, however, account for the extra fuel he was burning at the higher power setting.
Interestingly enough, most of the pilots who miscalculate fuel at the end of a long flight leg land just short (say, within 10 or so miles) of their intended destination. Sometimes on another airfield. Sometimes not.
I maintain that in most out-of-fuel accidents and incidents the real culprit is poor preflight planning. Pilots simply calculate the fuel exhaustion point of their aircraft, maybe slap a reserve on there (the FAA minimum on a VFR day is just 30 minutes) and then draw a line (most of the time with a flight planner app) that represents that time/distance on a chart and pick an airport near the end of it as their refueling point. Maybe they use an app to find the most competitive fuel in the area and fly to that airport. I get what they are doing. Pilots who fly light general aviation aircraft tend to want to fly long flight legs because they are perceived as most efficient. Many aircraft engines burn twice the fuel in climb as they do in cruise. They want to limit the amount of time they spend at those high power and fuel flow settings.
Well, efficiency be damned. When you are planning a flight, or for that matter, preflighting your fuel system, it makes no sense to set yourself up for failure by pushing the limits of your aircraft’s capabilities. Out-of-fuel accidents can be prevented so easily. Plan to land with twice the FAA minimum in fuel—the reserve recommended by the AOPA Air Safety Institute. Period.
Plan for unanticipated headwinds by underestimating your aircraft’s performance. I flight plan at a lower speed and higher fuel burn than what my airplane typically does. It is my cushion. I like cushions because they give me the wiggle room I need on days where the weather doesn’t play into my hand.
And do what I do: use a sophisticated flight planning tool such as those found in moving map apps, or browser-based tools such as AOPA’s flight planner, which
offers easy-to-use graphic tools for choosing good refueling points along any flight path. When programmed with your aircraft’s performance parameters and departure time the planner will color-code your course to indicate where you’ll need to land for fuel, based on the forecast wind. The magenta route line will turn yellow to represent the caution zone segment in which you have 60 to 90 minutes of fuel remaining. The course segment will turn red if less than 60 minutes of fuel remains. Current fuel prices at airports on or near your route pop right up on the planner. Just select one along the yellow section of your course and the planner reroutes you and includes the fuel stop. Best of all, you can email the route to your iPad or android tablet and it will interface into several popular moving map apps with a few clicks.
Then go fly your plan. You’ll thank me for counseling you to land a little more often on a long cross-country about the time you step out onto the ramp and stretch your legs a bit. Or maybe when you are availing yourself of those free homemade cookies and a fresh cup of coffee served up with a smile in so many of our wonderful independent FBOs. The difference in your overall en route time won’t change much, but the quality of the day is likely to be just a bit higher.
Give it a try. Let’s work to make 2016 the year that out-of-fuel accidents suddenly disappear from the NTSB’s graph of stupid-pilot-tricks.