Stress and Human Performance

On July 3, 1988, the USS Vincennes detected an approaching aircraft in the Persian Gulf, attempted verification, and then fired on and shot down the aircraft, all within a critical 4-minute span. The aircraft turned out to be a civilian Iranian airliner with 290 passengers and crew members aboard. The investigative panel who evaluated this accident found that although major hardware systems functioned correctly, the humans who operated these systems were under severe time pressure and operational stress that contributed to the Vincennes tragedy.

On February 22, 1994, USAir Flight 565, a DC-9 carrying 62 passengers from Washington to Boston, was forced to divert and make an emergency landing at New York's LaGuardia Airport because the airplane was about to run out of gas. Behind schedule in Washington, workers had forgotten to refuel the plane, and the flight crew had not checked fuel readings before takeoff.

In Tampa Bay during the predawn hours of August 10, 1993, a phosphate freighter collided with two barges carrying millions of gallons of jet fuel and oil, touching off a fiery explosion. With the outboard freighter and the inbound barges negotiating the bay's 600-foot-wide shipping channel, one party turned directly into the path of the other (exactly who did what remains a bit murky) and collided.

There were a number of contributing factors that led to these accidents. However, they are all similar in that they represent demanding task environments in which individuals must often perform under high stress. The crew of the Vincennes was under intense time pressure to identify a potential threat before it could endanger the ship, while the ship was lurching, lights were flickering, and communications were coming in simultaneously over left and right channels of operators' headphones. Commercial aviation has a strong safety record, yet

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