Pending legal action, private flying could get a lot less private. Through the Freedom of Information Act (FOIA), news agency ProPublica petitioned the FAA to release the list of operators who had blocked their tail numbers from Internet sites displaying air traffic control data. The FAA initially approved ProPublica's request and was ready to release the list, but the National Business Aviation Association has filed suit challenging the release of the data on grounds of security. A court will rule on the issue. Here's the background. Air traffic control flight data was released to the public about 10 years ago, which led to Internet access to IFR flight tracking of any aircraft's tail number through sites such as Flightaware.com. Access to ATC data has been a boon to charter operators for tracking their fleets and busy FBOs planning for incoming flights, but its availability also raised a major privacy issue. When the data became available, the NBAA instituted its Block Aircraft Registry Request (BARR) program, assuring aircraft operators they could block their tail numbers from public view. The ProPublica FOIA petition targets the list of those operators who requested their identities be kept from the public eye. The news agency has gone on record indicating it is looking for information on private use of corporate aircraft by executives, and wants the list to reveal who has hidden their flight data. You can still block your tail number from appearing on sites such as flightaware.com, but your request will place your name on the list of those who have blocked their data from public view.