Never sure why people think a chandelle is the way out of a box canyon. Have never seen it as a recommended practice in any mountain flying literature, including for the Mountain rating taught in Italy.
What about a stall turn (“hammerhead turn”) in such a situation?
MedEwok I assume you are being ironic :)
…or put another way let me count the ways a hammerhead turn might go wrong :)
…recall entry is as in a quarter loop so around 4.5 G and 130/140 mph in a typical sports level aerobatic aircraft
All these theoretical consoderations about tightest maximum rate turn whatsoever are of very little value when the average pilot gets caught in a valley. You have very different visual clues, you may even have difficulties to maintain your altitude because you don‘t have the horizon as reference.
I fly often in the alpine valleys. In 28 years of flying in the same airplane it never occured to me to even try a maximum bank minimal radius turn in a narrow valley. Best life insurance is to plan ahead and proper decision making. Even ,very experienced‘ pilots like the ones who did fly the swiss Ju-52 this august got caught in a valley they couldn‘t escape. First factual information released by the investigators suggest that the engine power just was not available for the tight turn they tried.
What Bleriot said! Agree.
MedEwok wrote:
What about a stall turn (“hammerhead turn”) in such a situation?
Probably not a great idea for the reasons @RobertL18C mentions and several more unless you happen to be a very current advanced aerobatic pilot and prepapred to do it at any time including in a C172.
Airborne_Again wrote:
I am thinking what to do I found myself in that situation. My first thought is:- Full power climb, trading airspeed for altitude.
- As airspeed decreased below Vx, approach flap, approach airspeed (1,3*Vso) and a 45° banking U-turn. (Into wind, if possible.)
ArcticChiller wrote:
Don’t forget that at 45° bank, the stall speed increases by x1.19. So I wouldn’t suggest a speed of 1.3*Vso for a steep turn. Just don’t bank that much. In slow flight I wouldn’t do more than maybe 25° bank. Airspeed (respectively ground speed) is much more relevant to reduce the turn radius.
I guess your point about airspeed depends on how much room you have!!! If you’re cruising along with 100+ kts, you can convert all that airspeed to turn performance. The lowering flap during the turn helps lowering the speed thus turn radius.
Of course if you see the problem appearing you would reduce cruise airspeed to a slower precautionary cruise speed, to create more time & space to consider the best course of action, and be better setup for tighter turns.
Disclaimer: don’t try this at home 
Slightly off-topic, i guess we are discussing another scenario where a chute may help save the day.
If they’d had the height to use a chute, they’d have been able to turn.
