10:05 a.m.-11:05 a.m. September 11, 2001: Andrews Air Force Base Tower Broadcasts Warnings that Planes Could Be Shot Down

The air traffic control tower at Andrews Air Force Base, near Washington, DC, broadcasts regular warnings over radio that any aircraft entering the restricted airspace around the capital will be shot down, even though, according to the 9/11 Commission, the president does not authorize the shooting down of threatening aircraft until 10:18 a.m. [9/11 Commission, 2004; 9/11 Commission, 2/17/2004; 9/11 Commission, 3/11/2004 ; 9/11 Commission, 7/24/2004, pp. 41] The Andrews control tower begins broadcasting warning messages over the Air Traffic Information System (ATIS) at 10:05 a.m. [9/11 Commission, 3/11/2004 ] The ATIS is an automatic information system over which “[p]re-recorded airfield advisory information is automatically transmitted at timed intervals over the airways on a specific frequency.” [US Air Force, 10/1/1999 ]
Planes Told They Could Be ‘Shot Down’ – A 9/11 Commission document summarizing key transmissions from the Andrews tower will show that warning messages are broadcast about once or twice every 10 minutes. The messages, which are all quite similar, include: “No fly notice. Remain clear of Andrews Class B airspace or you will be shot down,” and, “Any aircraft monitoring Andrews Approach Control frequency: remain clear of Andrews Class B airspace or you will be shot down.” [9/11 Commission, 2/17/2004] (Class B airspace is restricted airspace in which no one is supposed to fly without a working transponder and permission from an air traffic controller. The airspace around much of Washington is designated Class B airspace. [Washington Post, 9/12/2001; New York Times, 9/29/2001] )
Fighter Pilots Hear Warning – At least one of the warning messages is heard by District of Columbia Air National Guard (DCANG) fighter pilots who launch from Andrews Air Force Base at 10:42 a.m. (see 10:42 a.m. September 11, 2001) and by pilots launched from Langley Air Force Base by NORAD’s Northeast Air Defense Sector (NEADS) earlier on (see (9:25 a.m.-9:30 a.m.) September 11, 2001). DCANG pilots Marc Sasseville and Heather Penney Garcia are flying at low altitude over Washington, while the three Langley pilots are above them at around 20,000 feet. Although they are on different radio frequencies, both sets of pilots hear a message over a shared channel: “Attention all aircraft monitoring Andrews tower frequency. Andrews and Class Bravo airspace is closed. No general aviation aircraft are permitted to enter Class Bravo airspace. Any infractions will be shot down.” [Filson, 2003, pp. 82]
Officers Hear Warning – The warning messages are also heard by DCANG officers at Andrews. After hearing that violators of the Washington airspace will be shot down, Brigadier General David Wherley thinks to himself, “I guess that will be us doing the shooting.” [Washington Post, 4/8/2002; Vogel, 2007, pp. 446] Apparently referring to the warnings from the Andrews tower, Lieutenant Colonel Phil Thompson will later recall: “We kind of winced at that, because there are plenty of hard reasons to not shoot somebody down. We were really in an ID posture—and trying to really be careful.” [Aviation Week and Space Technology, 9/9/2002]
Shootdown Not Authorized until 10:18 – Although the first of the warnings is broadcast at 10:05 a.m., President Bush only gives authorization for hostile aircraft to be shot down at 10:18 a.m., according to the 9/11 Commission, in a phone call with Vice President Dick Cheney (see 10:18 a.m.-10:20 a.m. September 11, 2001). Furthermore, NEADS only learns that NORAD has been given clearance to shoot down threatening aircraft at 10:31 a.m. (see 10:31 a.m. September 11, 2001). The 9/11 Commission document of Andrews tower transmissions will show that the warnings are broadcast until at least 11:05 a.m., although presumably they continue after that. [9/11 Commission, 2/17/2004; 9/11 Commission, 7/24/2004, pp. 41-42]