Originally Posted by UAL T38 Phlyer

They approached each other laterally, from my perspective. Most pilots (even fighter pilots) spend the majority of their scan looking forward of the 3-9 line.

But additionally, I can still hear the words of my Aerospace Physiology instructor at Williams AFB during the classroom lectures prior to flying the mighty Tweet:

"Which airplane is the one you are going to hit? The one that doesn't move."

I had never thought of it that way before.

In fighters (at least, the courses I went through), this stationary target was called "on the CATA" (Collision-Antenna Train Angle). It meant if you were locked on to a guy and the antenna angle didn't change, he was coming straight at you.

Lastly, the human eye reacts to two major physical characteristics: contrast, and relative motion. The video seems to show relatively little relative motion, especially in the peripheral vison area.

Missiles work the same way: no motion, it's coming for you. Makes it tough to see and react to.

Very, very unfortunate accident.