> The screen showed the operator what objects were detected on radar, and if he clicked on an object, it would track it. But if the operator wanted to get more information about the object (in this case, by listening in on its radio signals) to find out what it actually was, he had to move a separate cursor and click on the object again.

> It's clumsy and unintuitive, and it made it really easy to forget which thing they were highlighting at any given moment -- the operator can be tracking one object and have it display the information for a completely different one because he forgot to move the other cursor. It's the kind of user interface that wouldn't make it out of the testing phase of a cheap browser game. And it cost the passengers of the plane their lives.

> That's because the operator in the USS Vincennes thought he was listening to the incoming aircraft (the Airbus full of innocent people), because that's the thing he selected, when he was actually receiving signals from a parked F-14 several miles away, because that's where his other cursor was.

> Granted, the transmissions alone wouldn't be reason enough to shoot down a plane: They'd also have to think that it was moving like an enemy aircraft. Unfortunately, the stupid system made that mistake pretty easy, too. Instead of telling the operators at the Vincennes if the approaching plane was ascending or descending, the system just showed them the present altitude on a smaller monitor. The operator had to write down or memorize the altitude, wait a few seconds, then ask again and mentally compare the two results to see if the aircraft was going up or going down.

> Because of this, a calculation error led an operator to report that the Airbus was descending toward the USS Vincennes, like a combat aircraft would, when it was probably getting the hell away from them as fast as possible.