An unexpected fallout from the September 2001 terrorist attacks has been a heightened interest in business aviation, largely in response to the passenger security and safety the medium has come to represent.

With the horrifying images of September 11 seared into the nation's collective memory, business aviation is pondering the ultimate impact from the terrorist attacks on New York and Washington, D.C., will have on operational freedoms.

Overall quality of engine bleed-air used to pressurize and ventilate commercial aircraft cabins was found to be ``excellent,'' according to a preliminary study commissioned by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASHRAE). Conducted by Germantown, Md.-based ENERGEN Consulting, Inc., and released this winter, ASHRAE Research Project 959 identified volatile organic compounds (VOCs) and other contaminants suspected of entering aircraft through bleed-air systems.