Just found the perfect example of windshear on a light aircraft.
One of my CFIs was killed by windshear.
I've experienced it twice, on late final around 50 to 100 feet above ground level.
The first time, I didn't react, just sat there and the Instructor slammed the throttle wide open so we missed going into scrub.
The second time, the CFI yelled "FULL TROTTLE" but I'd reached the end of the throttle sector and we went up like a lift.
You dont need to know the theory of it; when you fall it's just WOT and THEN fly it.
I timed this one at about 3 seconds from the point where he would notice the drop to touch down
In my cases I hadn't reached the runway; I counted 1.5 seconds from the time he would notice the drop to the time WOT would have arrested the drop and he could climb out.
You can put your stop watches on it and feel how much time you have to react.
We've talked in the past about building some actions, like EFATO initial response into muscle memory, where the average person starts to move in about 50/100 of a second, people with full currency and active about 20 to 30/100, and some down to 15/100. If it's not a built in response; if something happens out of the blue, the reaction time will be around 2 to 5 seconds or even longer if you are disbelieving of what's happening.
This is a good one to concrete in your head. Remember, I had made countles approaches and landings, but the first time, I would have started to respond after I hit the ground.
Windshear