Accident Rate vs. Advanced Avionics

by Harold Green
Published in Midwest Flyer – Dec 2016/Jan 2017

Recently, concern has been expressed that technically advanced avionics – including autopilots – may not have produced a significant reduction in general aviation accident rates. Nonetheless, there has been a gradual reduction in accident rates over the past few years, while there has been no significant change in the cause of accidents over the past two decades. What this apparently tells us is that the advanced avionics in our aircraft have not produced the significant reduction in accidents that was expected.

There may be several reasons for this. Our expectations may not have been realistic, the new technology may not adequately address the issues that cause accidents in the first place, and perhaps there are new issues brought forth by the presence of the new technology. This discussion focuses principally on instrument flight because this is the most demanding in terms of pilot concentration and hence should be the most sensitive to any effect advanced electronics might have.

Our expectations were probably raised beyond what was realistic. Initially, the hype was: “Gee, this whiz bang toy with a Primary Flight Display (PFD), and a Multi Function Display (MFD), showing us a map and all the instruments in a compact group, is really great and my flying will be so much easier.” Well, yes, it is neat, but based on cursory review of the latest Joseph T. Nall Report,* the practical effect to date has been marginal at best.

First, think of the “six-pack” instruments. While the PFD does bring the information closer together, it does not appreciably reduce the scan requirements for the pilot. And this, in my opinion, is in large part due to the fact that we really don’t scan the way the textbooks say we do. Of course, when we are first learning, we do what the instructor says. However, once we get past the learning stage, our scan consists of speed-reading a pattern. That is, we don’t really read the numbers on the gauges until there is a reason to. We just note the position of the needles, like speed-reading, and we read the numbers only when they move, but even then we react before we read them. Therefore, having an altitude and airspeed tape, which displays numbers only, is of little value for those who learned with the six-pack. While most tapes include a trend indicator, it takes awhile for pilots to include this indicator in their scan. The trend indicators are sensitive and jump around a bit.

There are still more pilots out there who have learned on the six-pack than have learned on the glass cockpit. These folks learned to scan the instruments via speed-reading, and find it more difficult to adapt to the speed and altitude tapes, than new pilots who have not developed a scan that needs to be modified. Therefore, I contend that for the majority of pilots, the PFD display offers little or no advantage in flying the airplane until experience has been gained. Even then the results in terms of aircraft flight are about the same as with the six-pack.

The next question is whether or not new technology addresses the issues that cause accidents. While we don’t have specific data to confirm or deny this issue, there is one point, which must be addressed. That is, most accidents are, and have been since records have been kept, the result of pilot misjudgment, rather than a problem with instrument interpretation or lack of flight data. We still try to fly longer than our fuel supply permits. We still mess up landings and we still fly into bad weather. And it still happens that someone attempts to park their airplane in a hunk of rock. Most of these causes are not related to ignorance or instrument interpretation on the part of the pilot. The actual cause lies within us. We cannot expect technology to correct these flaws in our makeup.

There is also the question as to whether or not new issues arise because of the presence of the new technology. One of the issues that arise with almost everyone, particularly flight instructors, is the time pilots spend looking at information, particularly on the MFD, where engine and navigation data is displayed.

For example, the time spent staring at a Lean Assist operation can be extensive. While the amount of information available is tremendous, the steps, and therefore, time and attention, necessary to access that information, can be extensive. This has the potential to distract pilots from traffic avoidance duties. However, there is no obvious indication in the Nall Report that this has had a deleterious effect.

The MFD provides a plethora of information, but also requires heavy pilot attention. In fact, the MFD is most likely to cause pilot distraction for several reasons.

First, the MFD requires multiple steps to access the information, which it contains. Second, the information contained in the MFD is not directly related to aircraft control, even though it is necessary to conduct the flight. However, based on accident reports, it is virtually impossible to determine what impact the MFD might have had leading up to the event.  This is NOT to decry the advantage of knowing weather, having airport data, and approach plates or en-route charts at hand in front of your eyes.

Another issue, which is not addressed by an accident summary, such as the Nall Report, is the type of flying we as general aviation pilots are doing these days. While the number of pilots in the U.S. continues to decrease, I do not have data concerning the number of hours spent flying IFR. The reason this could be important is that both the benefits and disadvantages of technically advanced aircraft are most evident in flight in instrument conditions.

A very distinct advantage that may be a significant factor in this whole issue is the autopilot. Today’s technically advanced aircraft usually include a very capable autopilot. This autopilot goes well beyond the old wing leveler of yore. Today’s autopilot is capable of coupling with the navigational aids; flying a complete instrument approach; providing a constant airspeed function, defined rate of ascent and descent; and generally holding the pilot’s hand while attention is devoted to advanced information systems.

In conclusion, I believe the jury is still out on whether or not new technology has provided a safety advantage. Yet, intuitively, we feel that it should. It may well be that due to changing flight habits, along with a changing experience base on the part of today’s pilots, it has prevented the accident rate from increasing. However, there is no question that modern avionics are a convenience, and that they have the potential to achieve the goals we assumed for them. We will examine this issue further in future issues of Midwest Flyer Magazine.

* The Aircraft Owners and Pilots Association publishes the Joseph T. Nall Report annually.

EDITOR’S NOTE: Harold Green is an Instrument and Multi-Engine Flight Instructor (CFII, MEII) at Morey Airplane Company in Middleton, Wisconsin (C29). A flight instructor since 1976, Green was named “Flight Instructor of the Year” by the Federal Aviation Administration in 2011, and is a recipient of the “Wright Brothers Master Pilot Award.” Questions, comments and suggestions for future topics are welcomed via email at, or by telephone at 608-836-1711 (

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