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News flash: Airplanes need fuel to flyNews flash: Airplanes need fuel to fly

Last January, we reported on an encouraging trend: The number of fuel-management accidents in fixed-wing aircraft had dropped by half in just eight years, from 150 in 2000 to 75 in 2008.

Unfortunately, the celebration seems to have been a little premature. Not only has that momentum not been sustained; if anything, we’ve begun regressing. Over the two succeeding years the number of fuel-management accidents crept back up to 89. This increase of nearly 20 percent from 2008’s all-time low came even as the total number of accidents continued to drop, decreasing 6 percent in those same two years.

While it’s true that at some point schools can no longer be blamed for the behavior of their former students—it seems a little unfair to point the finger at some long-ago instructor after an 82-year-old, 7,500-hour pilot ran his Baron out of gas in Alaska—it’s also true that just about every fuel-management accident represents a failure to learn (or remember) some crucial lesson from either primary or transition training. For analytic purposes, the Air Safety Institute classifies them into three broad categories. Complete fuel exhaustion can generally be attributed to poor flight planning plus faulty decision making in the air. This was a lesson that should have been absorbed back in pre-solo training: the utter importance of knowing how much fuel is needed for the flight, allowing for a diversion in case you can’t land at your original destination; of monitoring time and fuel consumption en route; and of making that decision to divert (if necessary) while you still have a comfortable reserve. It doesn’t matter whether the airplane is a Cessna 150 or a Gulfstream V; it’s the pilot’s responsibility to make sure the tanks don’t run dry. And that includes detecting indications that some of the fuel’s going someplace you didn’t intend—there’s no forgiveness if a loose cap or some other leak is the reason you came up short.

On the other hand, fuel starvation—where usable fuel remains somewhere on board but the pilot didn’t manage selector valves, pumps, and other plumbing well enough to get it to the engine(s)—usually results from gaps in that pilot’s knowledge of the fuel system. Sometimes those systems can be intricate and counterintuitive, as in the case of a 1959 Bonanza that had over time been fitted with six tanks, three fuel selectors, and two switches controlling which tanks were displayed on the gauges. The pilot glided for at least four minutes after his engine stopped, but hit power lines half a mile short of the threshold on a straight-in final to Henderson, Nev. As it turned out, the left main tank still held five gallons, but the main selector valve was found set to AUX. In that position, all excess fuel from the injectors returns to the left main tank.

Chances are that fact came up somewhere in his transition training. Still, it wouldn’t be surprising if he forgot it in the heat of the moment, especially after having owned the airplane for 11 years. Anyway, system complexity isn’t a factor in nearly as many starvation accidents as you might think. More than 80 percent are in piston singles, the great majority of which have only two tanks and one selector valve. (Incidentally, while there have been about twice as many accidents in Cessna 172s and 182s as in the various Piper Cherokee models over the past 10 years—largely a reflection of the respective numbers flying—they’ve actually had 25 percent fewer fuel-starvation accidents. Being able to set the selector to “BOTH” really does have its advantages.)

Contamination is the least common category of fuel mismanagement, causing about 10 accidents a year, and it’s almost always the consequence of inadequate preflight inspection. True, occasionally foreign matter plugs something up in a place the pilot can’t see—one Grumman Tiger that had recently been repainted lost power when paint chips clogged its fuel filter—but in the great majority of cases, the contaminant is water. Surprisingly often, these airplanes were being flown for the first time after extended periods of sitting outside. Even more surprising is how many of these pilots admit that they didn’t bother sampling the fuel, or that they decided to “test-fly” anyway after sumping substantial amounts of water (and maybe also other kinds of debris) from the tanks. This is another lesson that should have been driven home before they were ever signed off to solo: Don’t even think about flying if there’s any question about airworthiness. When in doubt, have it checked out.

Attitudes toward fuel management are another area where it’s worth making a strong impression on students while they’re still impressionable. Not only can it shape the rest of their flying careers, it might just determine how long those careers will last.

ASI Staff

David Jack Kenny

David Jack Kenny is a freelance aviation writer.

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