9:39 a.m.-9:59 a.m. September 11, 2001: Flight 93 Begins Rapid Descent Despite Being Hundreds of Miles from Presumed Target

At 9:39 a.m., after having maintained a maximum altitude of 41,000 feet for about two minutes, Flight 93 begins a rapid descent, going down at a rate of 4,000 feet per minute. At 9:46, it interrupts this, going up from 19,000 feet to 20,500 feet, but then resumes its descent at the slower rate of 1,300 feet per minute. At 9:59, it has reached an altitude of 5,000 feet. [National Transportation Safety Board, 2/19/2002 ] The National Transportation Safety Board (NTSB) will later describe this as a “surprising element in the navigation of Flight 93,” since the aircraft begins its “rapid descent from cruise altitudes while still approximately 260 nautical miles [about 300 miles] from the (presumed) target.” [National Transportation Safety Board, 2/13/2002, pp. 3 ] The target of Flight 93 is later believed to be either the White House or the Capitol building. [9/11 Commission, 7/24/2004, pp. 14] The NTSB will note that by the times Flights 11, 175, and 77 had descended below 5,000 feet, they were all within 10 nautical miles (11.5 miles) of their targets. “UAL 93, on the other hand, descended to 5,000 feet while still 135 [nautical miles] from Washington.” [National Transportation Safety Board, 2/13/2002 ]