the Canadian aviation community, such as the Air Transport Association of Canada and local airport authorities. Their counterparts in the FAA (United States) and other international civil aviation authorities were also kept apprised. Nav Canada Nav Canada set up two command centres, the Strategic Command Centre (SCC) and the Tactical Command Centre (TCC). The SCC, located at the head office in Ottawa and headed by Andy Vasarins, vice-president of operations, oversaw the entire crisis and ensured that information and resources were effectively shared amongst the TCC and other parties. The TCC was originally a training institute in Cornwall, Ontario, and headed by Kathy Fox, assistant vice-president of air traffic services. Its role in the crisis was to disseminate information amongst airports and control towers. To facilitate this, general managers from across Canada were present. After the immediate crisis passed, the TCC was relocated to the head office and its operations were merged with the SCC. The operation The operation officially began at 09:45 ET (13:45 UTC), when Ben Sliney, working in his first day in his position as the U.S. Federal Aviation Administration's (FAA) National Operations Manager, ordered all U.S. airspace to be shut down as a result of the attacks. Actions taken by Transport Canada After learning that the FAA had closed down U.S. airspace, David Collenette, the Canadian Transport Minister, gave orders that Canadian airports be open only for outgoing police, military, and humanitarian flights, and incoming U.S. bound international flights. This was the first time Canada had shut down its airspace. About 500 flights were en route to the U.S. at the time of the attacks. Transport Canada instructed Nav Canada to give permission for transoceanic flights that were at least halfway towards their destination (i.e. had already passed the point of no return across the Atlantic or Pacific Ocean) to land at the nearest Canadian airport, depending on their point of origin and remaining fuel. Planes were entering Canadian airspace at a rate of one to two planes per minute. During the operation, SitCen staff focused on two issues: where to land the aircraft, and how to screen, deplane, and clear tens of thousands of passengers through immigration and customs. CIC and CCRA brought in extra staff from other posts to clear the passengers. The first airport to receive diverted flights was Canadian Forces Base (CFB) Goose Bay, which received seven aircraft; fourteen other airports from