Air passengers should feel quite safe when the pilot is getting on in years, a new study shows. Older pilots actually show less decline in their aviation skills over time than their younger peers.

In the United States pilots are required to retire at 60, and opponents of this policy say that nobody has been able to prove that a decline in ability occurs at that age.

Like expert chess players and musicians, say Dr Joy Taylor and colleagues, highly skilled pilots have built expertise that can offset the loss of certain skills that comes with aging.

Their findings have implications for understanding the competence of all older workers, not just pilots, they add.

Taylor and her team at the Stanford/VA Aging Clinical Research Center in Palo Alto, California looked at 118 pilots ranging in age from 40 to 69, and followed them for three years. The pilots were divided into three levels of expertise based on their Federal Aviation Administration rating.

The pilots were tested annually for air-traffic controller communications, traffic avoidance, scanning instruments, approach to landing, and summary flight score.

The most expert pilots scored highest on tests of flight performance, and showed the least decline in their skills over time. Their performance was strong in communication and approach to landing. Level of expertise was more associated with a pilot's skills than the amount of time spent flying each year.

Regarding age, older pilots initially performed worse than their younger colleagues, but their scores showed a slower decline over time. This was primarily because the senior pilots showed more improvement in their traffic avoidance abilities.

"These findings show the advantageous effect of prior experience and specialized expertise on older adults' skilled cognitive performances," Taylor states in a press release accompanying the study.

"Our discovery has broader implications beyond aviation to the general issue of aging in the workplace and the objective assessment of competency in older workers."