United Airlines Flight 173 was operating a scheduled passenger flight from Denver, Colorado, to Portland, Oregon, when it encountered a significant issue with its landing gear. During its initial approach to Portland International Airport, the flight crew discovered that the nose landing gear did not indicate that it had been deployed. The captain, malcolm ”mac” orr, decided to circle the airport as they attempted to troubleshoot the issue, which extended the flight duration significantly. The crew engaged in discussions regarding their options while neglecting to monitor their fuel levels adequately.

As the aircraft continued to circle, it began to run low on fuel. The situation was tragically compounded by the crew's preoccupation with the landing gear problem, which led them to lose situational awareness. Consequently, the aircraft's engines lost power, ultimately leading to a crash in the neighborhood of Parkrose, just east of the airport. On impact, the plane collided with several homes, resulting in the deaths of 10 individuals: eight passengers and two crew members, while many other passengers survived.

The accident raised serious concerns about procedures in aviation safety. The post-accident investigations revealed critical deficiencies in cockpit resource management and communication among crew members. As a result, the Federal Aviation Administration (FAA) introduced new regulations focused on crew training and cockpit protocols, aimed at enhancing the safety of flight operations. This event initiated discussions about the importance of clear communication within the cockpit and the need for improved emergency response strategies in aviation.