On 11 September 2001, an aircraft closely resembling an E-4B was spotted and filmed orbiting the Washington, D.C., area by news outlets and civilians, after the attack on the Pentagon.[16][17] In his book Black Ice, author Dan Verton identifies this aircraft as an E-4B taking part in an operational exercise, and the exercise was canceled when the first plane struck the World Trade Center.[18] Air traffic control recordings and radar data indicate this E-4B call sign VENUS77 became airborne just before 9:44 am, circled north of the White House during its climb, and then tracked to the south of Washington, D.C., where it held in a holding pattern