Thursday, March 13, 2008

Aeronautical Decision Making

Aeronautical decision making (ADM) is a systematic approach to the mental process used by airplane pilots to consistently determine the best course of action in response to a given set of circumstances. The importance of learning effective ADM skills cannot be overemphasized. While progress is continually being made in the advancement of pilot training methods, airplane equipment and systems, and services for pilots, accidents still occur. Despite all the changes in technology to improve flight safety, one factor remains the same.the human factor. It is estimated that approximately 75 percent of all aviation accidents are human factors related.

Historically, the term "pilot error" has been used to describe the causes of these accidents. Pilot error means that an action or decision made by the pilot was the cause, or a contributing factor that led to the accident.

This definition also includes the pilot's failure to make a decision or take action. From a broader perspective, the phrase "human factors related" more aptly describes these accidents since it is usually not a single decision that leads to an accident, but a chain of events triggered by a number of factors.
The poor judgment chain, sometimes referred to as the "error chain," is a term used to describe this concept of contributing factors in a human factors-related accident.

Breaking one link in the chain normally is all that is necessary to change the outcome of the sequence of events. The following is an example illustrating the poor judgment chain.

A private pilot with around 350 hours was ferrying an airplane cross-country to a new owner. Due to time constraints, the pilot skipped dinner the night before and had no breakfast on the morning of the flight. The pilot planned to have lunch around noon at a fuel stop. A descent was begun from 9,500 feet, about 20 miles from the chosen fuel stop, due to haze and unfamiliarity with the area. When the airplane arrived at pattern altitude, the pilot could not find the airport. The pilot then circled north of the town, then back over the town, then flew to the west, then turned back to the east. The pilot decided to check for airport information in the Airport/Facility Directory, which was on the rear seat and not readily available.

Power had not been increased since the descent to pattern altitude, and the pilot had been holding back pressure on the yoke. While attempting to retrieve the Airport/Facility Directory, a loud "bang" was heard. Looking up, the pilot discovered the airplane was only about 200 feet above ground level. Increasing power, the pilot climbed and located the airport. After landing, it was discovered a fiberglass antenna had been hit, which damaged the leading edge of the left wing.

By discussing the events that led to this accident, it can be understood how a series of judgmental errors contributed to the final outcome of this flight. For example, one of the first elements that affected the pilot's flight was fatigue. The pilot understood that fatigue and hunger could affect the ability to fly safely, but let the desire to stay on schedule override the concern for a safe flight. Next, the rush to get airborne led the pilot to skip or postpone necessary aspects of preflight planning. Research before takeoff, with a quick review before descent, could have ensured a clear mental picture of the location of the airport in relation to the town. Copying relevant information from flight guides and other information sources is part of careful preflight planning. Studying the aeronautical charts and checking the Notices to Airmen (NOTAM) beforehand would have alerted the pilot to towers, terrain, and other obstructions in the vicinity of the airport.

Even without proper planning before the flight, good cockpit resource management and organization would have had the flight guide and any other necessary information near at hand, perhaps with the relevant pages flagged. Approaching the airport environment and flying around the area at traffic pattern altitude in hazy conditions could have interfered with other air traffic, and the potential for a midair collision is obvious.

In all circumstances, the pilot's first duty is to fly the airplane. Clearly that would include adjusting the power, setting the trim, and keeping track of altitude. This pilot was extremely fortunate—the outcome could easily have been fatal.

On numerous occasions during the flight, the pilot could have made effective decisions that would have broken the chain of error and prevented this accident. Making sound decisions is the key to preventing accidents.

Traditional pilot training has emphasized flying skills, knowledge of the airplane, and familiarity with regulations. ADM training focuses on the decision-making process and the factors that affect a pilot's ability to make effective choices.

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