Page 24 - June22Tv2

From the Flight Deck
by Kevin R. Dingman
Paper Airplanes – Reloaded
Continued from the May 2022 issue...
AYou Can Feel Your Innards Move
fter I slow to subsonic, the next check is the over-G limit function of the flight control computer. It should allow you to pull as hard as you want, as
quickly as you want, and not let the jet go to more than 9 Gs plus-or-minus point four Gs. As soon as you drop to subsonic, you roll to 80 degrees of bank and quickly pull; about 25 pounds of pressure on the stick. The G-suit squeezes the crap out of you, and you push back to stay conscious. A lot of people have said to me over the years that it must be fun to pull 9 Gs. Nope, 9 Gs hurts. You
can feel your innards move.
If you know anything about GLOC (G-loss of consciousness, pronounced G-lock), you know that the “onset” rate is a major factor affecting whether you black out or not. That means how quick- ly you go from 1 G to 9 Gs. The nerve cluster in your upper neck that makes you wake up from a dream when you think you’re falling, or makes you gasp when you feel zero-G unexpectedly, is the same one that tells your heart to beat faster when you pull Gs. The func- tion is to increase your blood pressure allowing you to stay conscious and keep most of your vision.
This cluster, however, isn’t “designed” to react to an instant 9 Gs; there’s a
22 • TWIN & TURBINE / June 2022
delay. Thus, the G-suit and the need for your physical reac- tion in preparation for the Gs. This test requires an instant onset rate to verify the computer can catch the impending over-G. Not good for the human body. We lost a handful of F-16 guys because they blacked out at some point in a mission – usually due to high onset rates and ran into the rocks. The good news is you only have to hold 9 Gs for a few seconds during an FCF.
Doing the Test Naked
At the end of the max-G check, you’ve used up a bunch of energy and slowed to less than 300 KIAS. This sets you up for the next gut-check. The flight control computer has another pilot-proof feature; it shouldn’t let you stall – ever. If the F-16 is stalled, it tends to go into a “deep stall” or “deep spin.” Picture a falling leaf with the nose pitching up, then down, then up, etc. Usually unrecoverable.
The stall is so potentially dangerous they put a special switch in the cockpit called “manual pitch override,” or MPO. Pushing this switch gives you extra stabalator (stabalateron!) travel to help increase the amplitude of the pitching moment in the stall. Hopefully, the extra amplitude in the down di- rection will be great enough to “fall” out the bottom of the