The fact that Andrews was the most knowledgeable person in terms of the vulnerabilities of information and communications networks for U.S. national security seems a worthy point for further consideration. That’s because so many inexplicable problems occurred with defense communications networks on 9/11, including the following.

There were serious problems with the National Military Command Center’s conference calls that morning. Important participants could not be connected or were repeatedly dropped from the calls, including the FAA.[12]
U.S. national security facilities were in an information void on 9/11. Agencies that should have known the most about an ongoing terrorist event were blind to the ongoing attacks.[13]
The SIPRnet did not have any information about the attacks even as late as the afternoon of 9/11.[14]
President Bush complained of poor communications in that he “could not reach key officials, including Rumsfeld” and “The line to the White House shelter conference room – and the Vice-President- kept cutting off.”[15]

— Read on digwithin.net/2014/06/04/andrews-and-saic/