Originally Posted by
North Shore
Assuming (I know..) no mechanical problems, and an undershoot, what's the time frame from recognition and full power application, through spool-up and the plane accelerating and beginning to climb?
Based on the general regulations and not considering the type:
Go-around performance considers engine thrust after 8 seconds of advancing the levers. That usually means the engines are designed to be close to full power at that point (otherwise you can't take credit for the thrust they can give). So one bound on the time is that 8 seconds.
A second item can be used to gauge this, and that's the AP minimum use height, which is often based on the height you'd lose if you had an AP failure/hardover, and had to react to pull up following the hardover - the height you'd need for all of that is typically in the 50-100ft range. So again, 5-10 seconds. (But that includes the failure and reaction, not just reaction)
Another guide is the fact that aircraft typically flare at 50 ft or so, and that's enough time to smoothly adjust the flightpath to level flight, more or less. A more aggressive flare type manoeuvre would reduce the height required to execute it by a bit.
Generally I've seen the actual aircraft response be pretty fast - once the control input is in, the aircraft starts to respond practically immediately.
If I had to pick a number, I'd say between 2.5 and 5 secs (25-50ft) to arrest the descent and begin the climb, with another 2.5-5 secs to get the full climb capability as the engines come up to power.
Based on where they seem to have hit, they seem to have been ~100ft low.