The US population is around 1/8 black. Which means, if every kid has an equal opportunity (in an absolute sense or on average) to develop the requisite skills to be an air traffic controller and if every kid was equally inclined to apply, and the application process were fair, then eventually around 1/8 of air traffic controllers would be black. Which seems like a good outcome.

If 1/8 of the population is black and someone is trying to get 1/4 of air traffic controllers to be black, that seems like a mistake.

Large American employers basically all face the same double bind: if they do not disriminate in hiring, they almost certainly will not get the demographic ratios the EEOC wants, and will get sued successfully for disparate impact (and because EVERYTHING has disparate impact, and you cannot carry out a validation study on every one of the infinite attributes of your HR processes, everyone who hires people is unavoidably guilty all the time). But if they DO discriminate, and get caught, then that's even more straightforwardly illegal and they get sued too.

There is only one strategy that has a chance of not ending you up on the losing end of a lawsuit: deliberately illegally discriminate to achieve the demographic percentages that will make the EEOC happy, but keep the details of how you're doing so secret so that nobody can piece together of the story to directly prove illegal discrimination in a lawsuit. (It'll be kinda obvious it must've happened from the resulting demographics of your workforce, but that's not enough evidence.) The FAA here clearly failed horribly at the "keep the details secret" part of this standard plan.

1. there is a test that is a decent proxy for job performance

2. the relationship between job performance and test score above some passing score is linear

These both sound "common sense", but I suspect fail for a huge number of real world scenarios.