The Question of Experience in Icing Operations

摘要

One of the most perplexing statistics to come out of recent icing incident investigations is the average experience of the flight crews involved. It turns out to be something on the order of 5500 hours. Often the crew has substantial time in type; the captain of the EMB-120 which crashed at Detroit in 1997 had 5300 hours, 2600 in type. His first officer had 2600 hours total time and 1100 of that in type. The captain and first officer involved in the Roselawn accident had 7900 hours and 5300 hours total time, respectively, with 1600 and 3200 in type. The captain of the ATP involved in the Cowly incident in 1991 had 8700 hours total with 1300 in type; the first officer had 900 total with 650 in type. Last year, the captain of a Saab 340 which fell out of a holding pattern due to icing in Australia, losing 2600 feet prior to recovery, had over 13,000 hours total; 3500 of it was in type. There is a widely held belief in aviation that experience is an essential factor in the equation leading to safety. Yet it is difficult to define precisely what experience is, what shades it comes in, and how it contributes to safety. The image called forth may have more to do with the spirit of rugged individualism which prevails in aviation history and in which pilots take great pride. Yet the question of how we know what we know often remains obscure.