Piloten klagen over reiniging luchtfilters

A United Airlines pilot agrees, saying he believes the filter systems should be cleaned after a couple of long-haul flights, depending on how full the planes are. “The filters get real dirty, and most manufacturers recommend regular cleaning,” he says, “but from my experience it can be several flights, sometimes a dozen or more, before the cleaning system is stripped down.”

This issue has been around since the early 1980s, when the carriers set out to increase fuel efficiency by introducing ventilation systems that recirculated cabin air. While older systems had used only fresh air – compressed, humidified and cooled by the engines – the new systems allow airlines to recirculate as much as 50 percent of cabin air, thereby decreasing workload demands on the engines and reducing the fuel needed to clean the cabin air.

Since then passenger and air-crew complaints about air quality and the contraction of colds and other respiratory illnesses have increased. The airlines have pointed to several studies to back up their claims that all is well with carrier air purity, including a 1999 study undertaken by scientists at the University of California at San Francisco and published in the Journal of the American Medical Association. That study involved more than 1,000 passengers flying between the San Francisco Bay area and Denver during the winter and early spring of 1999. About 19 percent of passengers on planes with recirculated cabin air reported colds a week after their flights. In comparison, 21 percent who flew in planes using only fresh air reported colds.