#23: United Airlines Flight 173 (1978)
Approaching Portland, Oregon, the crew became focused on a problem with the landing gear indicator. They circled the airport for over an hour, running through checks. In the distraction, they ran out of fuel. The engines died, and the DC-8 crashed in a suburban neighborhood, killing 10 people.

The accident shocked investigators, who found no mechanical fault beyond the crew’s poor coordination. Out of the tragedy came one of the most important reforms in aviation: Crew Resource Management, which trains pilots to share responsibility and speak up. It remains a cornerstone of modern cockpit culture.
