"Pilot error" once was a term used by investigators when they couldn't find any suitable explanation for an aircraft accident. But in today's world of CVRs and FDRs, we're learning that the human factors that contribute to aircraft accidents are far more complicated than anyone imagined. Today's pilots operate in a pressure-cooker atmosphere that provides precious little margin for error. This article explores some of the reasons we make the mistakes that result in accidents.
September 13, 1997
|About the Author ...
Brian Jacobson has over 12,000 hours
in all types of general aviation aircraft from trainers to jets. He has been
flying since 1970, and earned most of his certificates and ratings on the East
Coast in the early 1970s.
His first aviation employment was as sales manager at Air Worcester, Inc.,
an FBO in Massachusetts. Through the years, he worked for several FBOs selling
airplanes and flying charters. For nine years, he was chief pilot for a division
of ITT based in Providence, Rhode Island, and later was a bizjet captain for
Textron, Inc., out of Providence, Augusta, Georgia., and Pontiac, Michigan.
During those years, he flew real-world IFR in all sorts of weather and some of
the most congested airspace in the world.
Since 1988, Jacobson has been a member of
the National Aircraft Appraisers Association, and owns and operates a firm
called Great Lakes Aircraft Appraisal, appraising airplanes for buyers, sellers
and financial institutions. He also helps individuals and businesses buy
aircraft by evaluating their needs, recommending the type of aircraft they
should purchase, and helping them locate and procure those aircraft.
Jacobson is also a professional aviation writer. He is a contributing
editor for AVweb, Aviation Safety, and IFR
Refresher; a contributor to Plane &
Pilot; and can be heard on Belvoir Publications' Pilot Audio
In October 1996, he published his first book,
Flying on the
Gages, in which he discusses his experiences flying IFR. In May, 1997, his
second book was published:
Purchasing & Evaluating Airplanes.
Some pilots who hear the term "human
factors" dismiss whatever comes afterward because they think it is all a bunch of
psycho-babble. But if you take the time to think about aviation accidents it doesn't take
long to realize that every one of them has some form of human input — whether the result
of actions by the pilot, a controller, a mechanic, or a line crewman.
Years ago the term "pilot error" was used whenever investigators could not
find a suitable explanation for an aircraft accident. Most of the time the pilot was not
around to defend himself, so there were few unexplained accidents. Even today it is a
standard phrase that is used by those who fail to understand that it is much too broad in
With the advent of cockpit voice recorders at the
beginning of the jet age investigators began to realize that pilots were at fault for the
majority of the accidents, but they realized that the term pilot error was a misnomer that
explained little. The human factors that contributed to airborne accidents and incidents
were much more complicated than anyone imagined.
Cockpit voice recorders are not installed on light general aviation airplanes, so it is
not as easy to come to terms with the cause of an accident where a CVR is recovered. But a
thorough investigation of the circumstances usually will result in a probable cause that
Why Do We Screw Up?
Though many pilots bristle at the findings that their fellow airmen inadvertently or
intentionally screwed up, the truth is that pilots do some stupid things in airplanes.
Why? That's the question that often goes unanswered, and the only way to prevent similar
occurrences is to try to analyze the accident thoroughly, from a pilot's point of view.
Some accidents are the result of a pilot's not having the skill level that we expect of
him or her. For example, the failure of a vacuum pump in a single engine airplane during
instrument flight should not lead to a loss of control, but often it does. I remember one
fatal accident that occurred where the airplane was equipped with a stand-by vacuum
system, but the pilot failed to engage it.
Another common type of accident is fuel exhaustion. Most often than not a pilot
involved in a fuel exhaustion accident intentionally continued beyond what could be
thought of as a reasonable and safe use of his fuel resources.
Today's pilots live in a pressure cooker atmosphere. On the one hand there is the FAA
banging an iron gavel that few have the resources to fight, despite the public
misconception that all pilots are rich. On the other is a relaxation of training standards
that has occurred over the years in an attempt to turn around the decline in the pilot
population. You would think that the atmosphere would increase the awareness level of
pilots and their will to complete each flight safely and without incident.
Don't We Ever Learn?
Yet the same kinds of accidents continue to occur
month after month and year after year. That is why it is important to look intimately into
the human factors that lead to accidents and make as many pilots aware of the pitfalls as
possible. Some are not interested. These "macho" types can do anything, and
often they do, bending the metal and flesh because they neglected to consider the
foolishness of what they were doing.
Some human factors are easily understood. For example, fatigue has no place in the
cockpit, yet many pilots fly without regard to the length of their day or the need for
rest. Fatigue itself can be the cause of an accident or it can contribute to a pilot's
failure to act reasonably when a system failure or emergency situation exists. In either
case the results are not to our liking.
To be sure there are other physiological afflictions such as hypoxia, stress, illness,
and physical conditioning. Pilots must train to recognize physiological symptoms and
remain out of the cockpit when they are suffering from any of them.
Personality traits are liable to lead to other preventable accidents. Too often pilots
fail to recognize the change of attitude that is needed when one straps himself or herself
into the cockpit. Flying an airplane requires much more mental activity than most things
we do. The pilot must be constantly aware of what is going on inside and outside of the
cockpit. It is those who don't develop a solid awareness level, and those who disregard
the indications of trouble on the horizon (how much fuel is left versus time and distance
to the destination is a good example) who wind up in trouble.
Those who take risks on the ground are likely to do the same in the air. But anytime
the safety of flight is disregarded for any reason, the mental acuity must be even sharper
if an accident is to be prevented. But too often pilots don't understand the ramifications
of the actions they are taking.
Weight and balance is one of those areas that pilots frequently fail to give good
measure. Too often they will pack their airplanes as long as there is space without regard
to the weight of the people and baggage they are cramming in there, or how it will
influence the center of gravity. Some pilots only do half of the weight and balance
equation, totaling up the weights of people, fuel, and luggage, but neglecting to insure
that the load will fall within the aircraft's c.g. limits.
Is Training The Answer?
Often we are told that good training will insure that pilots work within safe limits,
but I believe that is so only for those whose attitudes on the ground and in the air
foster safe and sane operations. Training will do little for those whose attitudes are
less than desirable, yet when I read reports revealing the actions of the pilot after an
accident, sometimes I wonder why this person was flying at all.
So it is that human factors play an important part in aviation accidents, and we must
give them the attention they deserve. "Psycho-babble" they are not. It is up to
each of us to ensure that when we strap into our airplanes we are fit to fly, physically
as well as emotionally. And beyond that we need to know the limitations of our aircraft as
well as our own operational limits. If we work within them the chances of being involved
in an accident are significantly reduced. If we don't observe them just the opposite
occurs, and there may be a landing in our future that we don't walk away from.
NOTE: AVwebs safety editor Brian Jacobson
has produced a 35-minute audio tape entitled Human
Factors in Aviation Accidents in which he further explores the human side of why
accidents happen and what can be done to prevent them. The tape discusses in-flight
decision making, error chains, personal limits, personality traits (e.g., risk-taking,
lack of confidence), physiological factors (e.g., fatigue, stress), and a number of other
things that affect a pilots decision making abilities, and illustrates these issues
by describing and analyzing a number of actual accidents. You can order it on-line for just