The US Air Force has declassified a harrowing video showing the heads-up display of student pilot who passed out during a tight maneuver. Mercifully, his F-16 was equipped with a ground collision avoidance system, saving him from certain death.

It’s called the Automatic Ground Collision Avoidance System, or Auto-GCAS for short. It took nearly 30 years for the USAF to develop this system, requiring the help of NASA, Lockheed Martin, and its own Air Force Research Laboratory. The USAF introduced Auto-GCAS into its F-16 fleet in late 2014, and it’s already saved at least four pilots, including the one in this video.

Auto-GCAS works by continuously comparing a prediction of the plane’s trajectory against a pre-existing terrain profile. If the system predicts an imminent collision with the terrain profile—as it does at the 26-second mark of this video (you can see the two chevrons come together)—the autopilot kicks in. Writing in Aviation Week, Guy Norris explains what happened:

In this instance, an international F-16 student pilot was undergoing basic fighter maneuver training with his USAF instructor pilot in two separate F-16s over the U.S. southwest. The student rolled and started to pull the aircraft but experienced G-induced loss of consciousness (G-LOC) as the F-16 hit around 8.3g. With the pilot now unconscious, the aircraft’s nose dropped and, from an altitude of just over 17,000 ft., entered a steepening dive in full afterburner.

After only 22 sec., the F-16 was nose-down almost 50 deg. below the horizon and going supersonic. The shocked instructor called “2 recover!” as the student passed 12,320 ft. at 587 kt [675 mph, 1,086 kph]. Two seconds later, with the nose down in a 55-deg. dive, altitude at 10,800 ft. and speed passing 613 kt [705 mph, 1,134 kph]., the worried instructor again calls “2 recover!” In a little less than another 2 sec., as the now frantic instructor makes a third call for the student pilot to pull up, the Auto-GCAS executes a recovery maneuver at 8,760 ft. and 652 kt [750 mph, 1,207 kph].

And that’s when the student pilot finally woke up, pulling back on the stick. The radar altimeter suggests a minimum altitude of about 2,940 feet which, at that speed, isn’t a whole lot of breathing room.

A close call indeed—and kudos to the USAF for developing such an amazing system. It probably won’t be much longer before these high-speed fighter jets become fully autonomous, replacing us feeble humans.

[Aviation Week via Popular Science]