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It's not that simpleIt's not that simple

The last issue of Flight School Business noted an odd pattern in fixed-wing instructional accidents: They are least likely to be fatal when they happen on student solos, and most likely during dual instruction when the student already holds a pilot certificate. (Helicopter training accidents show no such pattern, which is further food for thought.)

An obvious explanation for this is that student solos are flown almost exclusively in daytime visual meteorological conditions (VMC). A larger share of advanced training takes place at night or in instrument meteorological conditions (IMC), when any accident is likely to be worse. Of all fixed-wing GA accidents between 2000 and 2009, those in daytime VMC had a 15 percent lethality rate compared to 25 percent in VMC at night and 70 percent in instrument conditions. Greater exposure to more hazardous circumstances can be expected to lead to more severe outcomes.

The numbers, however, don’t show this to be much of a factor. Only six of the 153 fatal accidents during dual instruction took place in IMC, and only 13 were in VMC at night. The proportion of daytime VMC accidents that were fatal was three times higher in dual primary instruction than on student solos, and during advanced dual, it was more than one and a half times greater than that. So what gives?

Differences in the types of airplanes being flown are another possible explanation. All but 10 of the 749 solo accidents were in fixed-gear singles, and lethality is well known to increase with the speed and weight of the accident aircraft. Sure enough, the proportion of crashes involving either twins or retractable-gear singles was four times as high in advanced as in primary dual instruction (47 percent compared to 12 percent), and this accounts for some of the difference: These aircraft were involved in almost half the fatal accidents in advanced training (49 percent) compared to just 22 percent of those during primary.�

But that’s still not the whole story. If we only look at accidents in fixed-gear singles, we still find almost twice the lethality in advanced instruction, 18 percent vs. 10 percent. So although the make-up of the accident fleet does seem to be a factor, something else is clearly going on as well.

Two risk factors emerge from the individual reports. Advanced training does involve more demanding maneuvers. For example, fatal accidents occurred while attempting aerobatics and during spin training, neither of which is typically part of the primary curriculum. (Although a handful of fatal spin-training accidents did take place in primary training, most involving instructors whose employers hadn’t authorized them to teach spins.) The elements of the commercial and ATP curricula are not intrinsically dangerous, but they are less forgiving than the private pilot maneuvers and require consequently more careful planning and greater attention to detail—particularly details such as entry altitudes and obstacle clearance.

Another difference is more subtle, but possibly more important. Primary students do most of their training in a single model, usually one their instructors fly day in and day out. One-third of all fatal accidents in advanced training, on the other hand, happened during flight reviews or new model checkouts—more than in instrument and multiengine training combined. A flight review might seem like the least demanding of a CFI’s assignments, but an instructor lacking extensive make-and-model experience may be a little too ready to defer to the customer—particularly a customer who owns the airplane—while the pilot being reviewed might put too much trust in the instructor’s ability to keep them both out of trouble. Unexpected risks also attend checking out even experienced pilots in equipment that’s very different from what they’re used to. A Boeing 747 captain’s instinct to flare 40 feet above the runway may be hard to overcome. Unfortunately, the circumstances of these accidents usually make their precise dynamics difficult to reconstruct.

David Jack Kenny is manager of aviation safety analysis for the Air Safety Institute and an instrument-rated commercial pilot.

ASI Staff

David Jack Kenny

David Jack Kenny is a freelance aviation writer.

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