Acceptable Errors

Safety

Since the late 1970s, safety-conscious airlines have been pinning their flight safety hopes on human factors (HF) education to reduce mistakes and thus accidents. Airlines which have embraced and practiced HF concepts such as Crew Resource Management (CRM) have seen improvements, but the decrease in the accident rate is still not good enough.

"Good enough" is relative. The measurable benchmark is the average number of airline accidents over recent years, which has stoped improving and appears to have "levelled out". If safety rates remain more or less the same, however, and the world fleet and air travel increases, the number of accidents annually may rise, alarming the public and damaging business.

Since aeroplanes and their engines are becoming more reliable, and because aircrew error is judged to be a factor in well over half of all serious accidents, the elimination - or at least reduction - of human error has been the goal for the last 20 years or so.

PILOT INFALLIBILITY
Things are now changing radically, however, as HF studies in the cockpit and in industry have advanced the understanding of what can realistically be expected of human beings at work. Not surprisingly, pilot infallibility has been ruled out, to be replaced by the concept of "acceptable error."

Applied to the flightdeck, this concept could send shockwaves through a training system which has traditionally used errors during training flights and checkrides as the primary direct, quantitative measure of pilot safety and competence. Airline or aviation authority checkpilots have largely catalogued errors in procedure, technique, or the spoken word, then passed or failed the pilot on the score. Some captains made little distinction between large and small errors, or whether they had secondary effects or not; the quantity was primary.

Now it is proposed that check pilots should stop being "error-detectors" and start to observe how crews manage the consequences of any errors they make so as to ensure that safety is not compromised. Any astute examiner should be able to recognise genuine incompetence, so that is not the issue.

CRM concepts, which shifted the emphasis to crew efficiency in carrying out the overall task safely, have already modified the "trapper" training-captain mentality, but the concept of acceptable crew error may require a major change in the mindset of today's average company training captain or check pilot.

If the consensus reached at October's International Air Transport Association Human Factors Seminar at Warsaw, Poland, is an indicator of things to come, however, the "Error Management" concept is definitely on its way into flightdeck training and checking.

MANAGING MISTAKES
No matter whether the speakers were academics, aviation psychologists, pilots or airline safety officers, they all agree that the new aim in line-flying checks and CRM-based Line-Oriented flight training (LOFT) will not be error elimination but error management.

Professor Robert Helmreich, director of the University of Texas' aerospace crew research project, agrees: "The errors are not the issue. It is whether or not they are resolved and have no consequences which matters." The head of the International Civil Aviation Organisation's (ICAO's) flight-safety and HF programmes, Capt. Dan Maurino, agrees, explaining it would be unnerving to to be a check captain to a crew which made no errors at all in a LOFT trip or line check, because there would be no way of knowing how they would react when they did make a mistake. Mistakes are only a matter of time, even for the near-perfect pilot.

Dr. James Reason of Manchester University, UK, a psychologist recognised worldwide as an authority on HF and human error, says "The best people can make the worst mistakes. Inattention, forgetfulness, preoccupation are the least manageable parts of an error sequence. Managing error-producing situations is better."

ERROR CONTAINMENT
Most organisations, Reason says, focus on the person. "They blame and train; write another procedure, search for a missing piece of knowledge (in the person); or an inherent tendancy to make an error...[however] it is better to try to eliminate error-provoking situations." Since error will still occur, however, Reason says that error containment is an essential procedure.

To reduce the chance of error in flight decks, some airlines use standard operating procedures (SOPs) and others say that automation is the answer. Not only can these create their own problems, however, but the approach is wrong, maintained Dr. Gary Klein of aviation consultants Klein Associates, who says that "procedure is no substitute for experience." He observes that Gandhi said that India's British rulers believed that they could create a set of laws so perfect that "...people no longer have to be good." Procedures are useful, however, not just in terms of checklists which cut our errors of ommission, but to help in what Helmreich calls "uncertainty avoidance", which some cultures appear to find more necessary than others.

Klein says that it is not lack of error, however, but total pilot situational awareness which is the keystone of a safe flightdeck crew. Situational awareness, however, is impossible for a crew with no awareness of a situation, he points out. One of the reasons why pilots struggle with computerised flight management systems, says Klein, is that becoming familiar with all their modes and quirks takes time. Situational awareness can suffer in the meantime, and always does when automation produces a surprise.

The University of Illinois' Dr. Nadine Sarter, a memebr of the team which produced the US Federal Aviation Administration-led international report on HF in highly-automated flight decks, chose the 1994 China Air Lines accident at NAgoya, Japan, as a classic example of how automation, through mode confusion, can destroy situational awareness.

It was chosen also, however, as an indictment of the kind of pilot training which the ICAO's Maurino criticises as as being based on 1970s concepts for a 1980s airliner (the Nagoya accident involved the Airbus A300-600). Maurino is not the first to talk about safety being a "culture" but he attemps to define the basic components of safety culture. Safety starts as a social value based on the perceived value of human life, he explains. Organisational or corporate values are rooted in the prevailing social views. In the end, however, safety is, as Maurino puts it, "a subjective process of risk evaluation and acceptance."

There was universal agreement at the seminar that a blame-free regulatory and corporate culture is essential to any plan to upgrade airline safety. Under the reverse, a punishment based culture, pilots keep potentially useful information to themselves, so that nothing can be learned about training or about Reasons's "error-producing environment."

Maurino describes the pilot as the whole aviation system's goalkeeper, and slams a system which, he says, provides pilot training based on 1970s principles employed in a 1980s-designed aircraft flying in the 1990's environment..."So long as we have our current reactive attitude [to flight safety] we need accidents to know when we are overstepping the boundaries."

An accident, at present, is the main stimulus for safety advance, Maurino says. Apart from the moral implications of such an approach, it is not even effective, he maintains, because accident investigators today do not consider it their task to investigate in any depth the HF contribution to an accident. Until they do, Maurino insists, lessons from accidents "...will continue to reinforce areas of safety which are already very good, and fail to deal with the weaker aspects."