At a recent international symposium on aviation human factors, one of the interesting sessions described an FAA study attempting to answer what traits might predict accident prone pilots.
A number of large aviation organizations – airframe manufacturers, airlines, pilot organizations and the NASA Ames human factors directorate – sent representatives to engage in what turned out to be a lively and interesting discussion. In the study, more than 4,000 pilots were asked to answer various questions about their background, training and attitudes. Among those who answered the survey, about half had experienced an official accident. The survey was structured to obtain a fairly representative sample of both the accident-free and accident populations.
One striking finding was in the number of pilots who had multiple accidents on their records. One individual had 15. Since the identities of the pilots had been completely removed, researchers were unable to go back to the individual and ascertain whether that was a misprint or not. Regardless of that single data point, I was somewhat surprised when I saw the number of pilots with multiple accidents.
Are these people truly accident-prone pilots, conducting themselves in risky manners, or are they just unlucky? Face it, many pilots have been close enough to an accident to see it coming, but managed to avoid it by circumstances that can only be described as luck. Ever landed sideways during a brisk crosswind and almost departed the runway? Ever looked at the fuel bill after topping the tanks and only then realizing how close youd come to an unintentional glider flight? Indeed, many pilots have been lucky enough that they cant point a finger much at those who have been unlucky.
But that doesnt alter the original question. Are some pilots more accident prone than others? When I was a Designated Pilot Examiner, I administered practical tests to some applicants who quite honestly left me uncomfortable about issuing a pilot certificate.
However, when I attended initial training for designees in Oklahoma City, the FAA instructors impressed upon us that our personal feelings should have no bearing on the applicants outcome. The FAAs official bottom line is that if the applicant meets the practical test standards, the applicant gets the certificate.
In one instance, I knew down deep that the candidate would go right out and try to stuff three of his wives and all six kids into a 6 seat aircraft, but there was nothing I could do about it.
It turns out I was right. He got away with poor decision-making for a while, but then he iced up in instrument meteorological conditions – while he was not instrument-rated – and had to make a not-so-graceful precautionary landing. In all of his mannerisms, he exhibited a strong disdain for rules and procedures, attributing rules and procedures to those Washington bureaucrats who dont know nuttin.
But many of the rules and procedures are written in blood, because Mother Nature and the laws of physics can be very humbling teachers. Could that accident have been predicted? Clearly, that answer is yes. In my opinion it was just a matter of time before his risk-taking caught up with him. Such risk-taking behavior has a decent probability of leading eventually to the unhappy ending of a flight.
A Tale of Woe
Other pilots dont deliberately take on high-risk activities but somehow still manage to get unlucky and have accidents. Take for example pilot A. Pilot A was flying an aircraft with retractable gear whose warning horn would sound each time the throttle was retarded to idle if the gear was up. Once when Pilot A was giving flight instruction out in the local training area, he decided to pull the circuit breaker to silence the warning horn during the flight.
Upon completing the training and returning to the airport, he forgot to push the circuit breaker back in. On this day, Murphys Law caught up to him and he landed gear up. This kind of accident has happened to many pilots, so it doesnt make pilot A unique by any means.
Pilot A continued in his flying endeavors. While taxiing a light twin out of the ramp, the pilot was interrupted by a radio call from a dispatcher and left the right fuel selector in the crossfeed position.
During the flight, the pilot noticed the right wing seemed a bit heavy and corrected with aileron trim. He did not, however, determine that both of the aircraft engines were feeding off of the left wings reserve fuel tank. After two hours of flight, the right engine quit. Then the left engine failed while the aircraft drifted down into a deep canyon.
The pilot selected a gravel bar in the river for landing and on short final raised the landing gear. The aircraft struck the sand bar and sank in 10 feet of water. Distractions have caught many pilots and interrupted the checklist flows. Circumstances like this can happen to almost anyone, but the lucky and the attentive usually catch it before it catches them.
Pilot A was undaunted and continued flying. Several years later, he was flying a twin-engine turboprop. The aircraft is steered on the ground by a nosewheel tiller that is located on the yoke. He airlifted some supplies into a remote airstrip and was returning to the home base. Upon touchdown, the aircraft immediately veered sharply to the left, departed the runway and came to rest in a marsh area 375 feet from the runway.
The aircraft and engines sustained substantial damage. The nosewheel steering tiller was found in the fully deflected position. The after takeoff and before landing checklists for the aircraft both required the pilot to check the position of the nosewheel tiller, but apparently this had been overlooked. Pilot A was fired from that job but went to fly for a major airline immediately afterward. Ironically, of the pilots I know personally flying for one major airline, 80 percent have at least one pilot-error accident on their records.
The Door to Perception
Its easy to quantify some factors that can lead to accidents. If your hearing or eyesight deteriorates substantially, it stands to reason you may be more prone to have an accident. Therefore, aeromedical examiners have established acceptable limits for sensory organs such as eyesight and hearing.
But how about perceptual skills? It seems like some pilots can be looking straight at another aircraft but dont seem to see the potential for a traffic conflict. One of the traits that affects the pilots ability to detect an upcoming threat (assuming their senses are working all right) is their ability to distinguish the critical incoming signal – radio communication, visual appearance of another aircraft, the airport – from all the other sensory noise impinging on them. Just as some pilots seem to have outstanding skills at detecting an upcoming traffic conflict, others tend to miss the potential. Still others are more prone to call a false alarm when the potential for conflict is small.
The same person can function at different levels. When your attention is sufficiently high, you are more likely to detect the traffic conflict, but if youre too excited you may react too quickly and react to false alarms. Being overly excited is a trait generally incompatible with aviation.
Pattern recognition is a very important step in the decision-making process, but seems to be the least understood. This is the stage where all of the incoming sensory signals – sight, hearing, feeling, smell – are integrated into a single interpretation of whats happening at the moment. During a takeoff, a pilot is bombarded by incoming signals such as the rush of air over the aircraft, the increase in noise, the feel in the bottom of the seat as the aircraft accelerates and the movement of the airspeed indicator.
As the flight hours accumulate, you begin to recognize the pattern of sensations as a takeoff and can sometimes detect a slight anomaly just because the whole package isnt quite like it ought to be. That can be good, because it can tune you in to problems you might otherwise not detect, but it can also be a costly teacher. Formal structured training is a safer substitute for learning some of the subtle insights pilots rely on for nearly every flight, such as reading a weather radar picture.
Can perceptual skills be measured and quantified? Yes, they have been for years, as a matter of fact, and some airlines employ psychological tests to screen out applicants who dont meet their standards. In the Part 91 world, of course, pilots are free from such tests and are left to their own devices as to whether they have the perceptual skills to keep flying.
One thing about perceptual processes is that they are limited by the pilots ability to pay attention. That makes pilots very susceptible to distractions, some more than others.
Airline cockpits have multiple crew members with overlapping procedures, so that the chances of being distracted and missing a critical item are lessened. Aircraft designers have installed warning devices on the more critical devices to help warn pilots that they have forgotten an item.
The taxi process can be loaded with distractions. The crew is performing the taxi checklist and listening to what can be complicated taxi instructions over congested radio frequencies.
In Part 91 flying, the pilot might be all alone in getting those checklists done, and it is very easy to get distracted by a cockpit duty or dealing with a passenger. Its easy to look down for a second at a chart and strike a propeller on a runway light.
There are psychological tests available that test pilots for the ability to do multiple tasks at the same time, measuring both the accuracy of the persons efforts, and their ability to divide their attention between the multiple tasks.
The ability to concentrate, manage workloads, monitor and perform several simultaneous tasks are necessary traits for the successful pilot. Obviously these skills can deteriorate with age, but the whole question of when those skills have deteriorated enough that a pilot needs to discontinue flying is a gray zone that isnt answered yet.
By the way, having good sensory or perceptual traits doesnt guarantee an accident-free flight career. The truth is, many pilots are basically lucky that they havent bent metal.
The case of the L-1011 that encountered a massive wind shear and microburst during approach into Dallas-Fort Worth in 1985 is such an example. Every single airline pilot flying into Dallas at that time was making the same decision: to continue their approach. None of the pilots were aware of the massive thundercloud building overhead.
The pilots of the ill-fated L-1011 were blamed for faulty decision-making when in fact they made the same basic decision as many other pilots that day. Yet the other pilots have no accident on their record and in the eyes of the law they are regarded as safe pilots. The L-1011 pilots, however, were faulted for the same decision. The bottom line is that avoiding an accident doesnt necessarily imply it was a safe flight.
A pilot with good sensory and perceptual traits can still be accident-prone because of his decision making. Consider the case of the two active duty Air Force pilots who rented a Cessna 172 and proceeded to buzz boats on a lake and do aerobatics adjacent to a cliff.
Both of these expensively trained aviators had gone through extensive screening for the sensory and perceptual traits. Through the military training process, they had received hundreds of hours of formal instruction on aerodynamics, judgment and safety. Presumably we would expect military officers to exhibit discipline, but on this day, such was not the case. So how did these two officers slip through the screening process, and could their accident have been predicted?
Clearly the aeronautical decision making of the two Air Force aviators was seriously flawed. A well-regarded study found that 51.6 percent of fatal accidents in general aviation were due to faulty aeronautical decision-making.
Pilot decisions are affected by a myriad of factors, to include experience, training, memory, and risk-taking tendencies. This accident ties in closely with the first findings of this research group.
The researchers found that pilots who had a pattern of engaging in unsafe acts such as buzzing, entering IMC without a clearance, and running low on fuel were among those most likely to have an accident. That makes sense. You might get lucky buzzing your house on several occasions, but soon enough the odds of having a stall/spin at that low altitude begin to build.
The next trait that correlated fairly highly with accident-prone pilots was thrill and adventure seeking. That makes sense, too. The two Air Force pilots probably entered military aviation partly out of a desire for adventure and the thrill of flying high-performance military aircraft.
But having this trait doesnt necessarily seal your fate as ending with a smoking hole. Personalities tend to remain quite constant throughout peoples adult lives. Dramatic, lasting change generally happens only in response to extraordinary circumstances.
But there are many other factors that influence decision-making besides personality, not the least of which is attitude.
Ive watched with amusement as my college classmates have evolved from thrill-seeking cadets, where conduct such as buzzing bridges was considered a badge of honor. Now they are on the back side of 40 and sit up front in an airliner. Their idea of a great flight means a soft landing, everything done by the book, maybe getting lucky and having a leftover meal from first class, and no hassles from the FAA. The financial and career consequences in commercial aviation of deviating from standard procedures can be disastrous and serve as a strong motivational factor.
Nature and Nurture
An additional motivational factor in aviation is the expectations of your friends. There is strong evidence that pilots live up to – or down to – the level of expectation in their aviation environment.
In commercial aviation, there is a strong cultural norm that expects professionalism and adherence to standard procedures. During this conference presentation, I happened to be sitting with a handful of other air carrier pilots, and interesting enough, even though we had never flown with each other, there was a distinct expectation within the group that nothing less than professionalism and adherence to the standard operating procedures would do.
That said, we unanimously determined that there is a very distinct difference in the cultural norms at our local general aviation airports.
In general aviation, cultural norms sometimes encourage risk-taking or breaking FARs. Macho flying, thrill-seeking and a distaste for FAA interference leads many pilots to try to do their own thing on their own terms.
If your flying club or local airport has a culture that rewards bravado and macho risk-taking, you arent doing yourself any favors. Culturally reward your fellow pilots who make the tough decisions to divert, or not to fly, rather than the events in which fellow pilots took extraordinary risks and are now boasting about it.
-by Pat Veillette
Pat Veillette is a safety researcher and ATP with more than 23,000 hours.