No matter the mode of transportation, we always investigate to see whether fatigue has played a role in accidents and incidents. We look at when the accidents occur: during the day, or at night. We look at the number of work hours people put in right before accidents and incidents occur. We look at how many hours of sleep they had, not only in the 24 hours leading up to the accidents, but up to 72 hours before, and even further back. We always look to find out whether fatigue has played a role in accidents and incidents. If so, we include this in our findings.
Since 2000, fatigue has played a role in approximately 20 air transportation accidents we've investigated, 15 of which involved crew members, the pilots. A number of these accidents involved private aircraft. We have investigated five or six cases involving commercial airline pilots.