Week 11: When protection becomes the problem

The deep stall, the switch that gives your authority back, and the altitude below which no recovery fits

3 May 2027

Week 3 argued both sides of whether a flight control system should be able to refuse you. This lecture is the case that settles least comfortably.

There is a corner of this aircraft’s envelope where it is stable in a state you do not want: nose high, wing not flying, controls in disturbed air, descending. The flight control system holds it there, correctly, according to logic working exactly as specified. The input that would break it out is one the angle-of-attack limiter exists to prevent — so the protection that keeps you out of this state on every other day is, on this day, the reason you cannot leave it.

Hence the override, which is the design admitting the argument has two sides. Flip it and the limiter is gone, along with everything it was protecting you from, and the recovery becomes available: rock the aircraft in pitch, in phase with its own oscillation, until the nose falls through.

It costs altitude. The lecture spends its second half on how much, under what conditions, and on the number that follows from it — the altitude below which you stop attempting the recovery and use the seat instead.

That number is different for each of you. It is not issued by the school, and you defend yours in the period. It is the same question asked in week 1, in the hangar, with the aircraft switched off — you have had eleven weeks to get a better answer.

Reading#

The abnormal procedures section, and your own written account from week 10 of the point at which you were furthest behind the aircraft.