Regular readers of the Air Safety Institute’s annual Nall Report (yes, both of you) may have noticed at least one encouraging trend in the fixed-wing GA safety record of recent years. The number of accidents due to fuel mismanagement dropped by half in 10 years, from 150 in 2000 to 74 in 2009. This marked a genuine improvement: The overall number of accidents decreased by less than 20 percent over the same period. In 2000, errors in fuel management caused a little more than 10 percent of all fixed-wing GA accidents; by 2009, it was only 6 percent.
The reasons remain mysterious. While you wouldn’t think aviators would need to be reminded that they’d rather not run out of gas, efforts at public education probably haven’t hurt. The FAA and Air Safety Institute have made strenuous efforts to raise awareness of the problem, as have type clubs and other public-interest groups. Improvements in cockpit instrumentation have been cited as a possible factor, although it’s not clear it has spread to enough of the fleet to account for such a dramatic improvement.
One hint has emerged from the Air Safety Institute’s updated study of the safety record of so-called technologically advanced aircraft, scheduled for publication in the first quarter of 2012. The project tracked more than 22,500 piston aircraft manufactured since 1996 by seven North American manufacturers. Between 2001 and 2010, they were involved in 740 accidents. Only 9 (1.2 percent) were ascribed to fuel mismanagement, and it won’t steal too much thunder from the main report to mention that panel configuration made no difference whatsoever in this respect. Out of 540 accidents in airplanes with conventional analog panels, six (1.1 percent) were blamed on fuel management, as were three of 232 (1.3 percent) in the glass-cockpit versions of the same models.
There were 1,030 fuel-management accidents on noncommercial fixed-wing flights during that decade, so the nine in airplanes built since 1996 made up less than 1 percent. Their share of the active GA fleet increased from about 2 percent to 10 percent during the same period, and there’s some evidence that new aircraft tend to log more time than older ones. So it seems pretty clear that fuel-management accidents are far less common in new airplanes, even compared to earlier editions of the same models. What’s not as clear is why.
It doesn’t seem likely that they do a great deal better at avoiding damage during forced landings, and thereby also avoiding the definition of an accident and its subsequent report. Odds are they genuinely run out of gas a lot less frequently, which is curious. After all, fuel management has almost nothing to do with range or efficiency per se; it’s almost entirely a matter of planning and verification. Fuel injection has become increasingly popular, and may provide more predictable fuel burn than carburetors, but that doesn’t change the basic responsibility to be conservative in estimating flight times, en route requirements, and reserves. Fuel totalizers can measure use with great precision, but the results are no better than the initial settings, and they don’t detect fuel lost to loose filler caps or other leaks. Range rings and audible warnings provide a backstop for sloppy planning and complacency in flight, provided the pilot reacts appropriately and still has a fuel stop within range.
In any case, the impressive record of the newer aircraft is only part of the answer. By itself, the increasing share of newer aircraft in the active fleet only accounts for about one quarter of the overall improvement. Changes in the model mix, with lines no longer in production being replaced by those that are, may also be a factor—but as a group, that part of the active fixed-wing fleet built before 1996 has seen the prevalence of fuel-management accidents decrease by about one-third.
Somebody out there is doing something right. We need to figure out what, and do more of it.