The Times found — through an analysis of FAA records and a NASA aviation database — that close-call incidents like these are often the result of human error, such as mistakes made by air traffic controllers who are chronically understaffed.
The recent rise in close call incidents involving commercial airlines is in part due to a widening hole in what's called the "Swiss cheese model," a framework for ensuring safe traveling. Under the model, the idea is that the different factors that go into ensuring planes land safely all have certain weaknesses. Those vulnerabilities could include the weather, a pilot's amount of sleep, wildlife, what the pilot ate for breakfast, or other human error. When you layer enough pieces of holey cheese, and make sure the holes don't line up, it creates a solid layer of security against disaster. In this case, air traffic controllers are a key piece of cheese, making sure that the holes are caught by someone monitoring the situation on the ground.
Except there's not enough air traffic controllers. A government audit released in June found that 77% of critical air traffic control facilities in the US are staffed below the recommended threshold.
The report concluded that the FAA "lacks a plan to address" the shortages, noting that due to training delays caused by COVID-19, the agency cannot ensure it will successfully train enough controllers in the short term.
The shortages aren't due to a lack of interest — the FAA received over 58,000 applicants for 1,500 air traffic controller positions (which pay a median salary of nearly $128,00) last year.
But new hires can't immediately start on the job. Air traffic controllers have to go through rigorous training that can take over three years to complete. In addition, applicants must be younger than 31 years old and are required to retire by age 56.