Part 3/9:
The 9/11 Commission referenced two primary sources for their timeline—the ACARS data and air traffic control recordings. However, there are criticisms of these sources. The ACARS data noted that the flight was grounded at 8:38 a.m., but also exhibited a troubling 20-minute gap in data transmission. Concurrently, air traffic control transcripts corroborate that Flight 93 did take off, albeit without explicit timestamps that could confirm a departure at 8:42 a.m.