[flyguy]

Anybody fortunate (!) enough to be familiar with EASA NPA 2015-13 and Rule Making Task .0581 on Upset Prevention and Recovery Training (UPRT) will be aware that the regulators deem it necessary for commercial pilots to be aware of the differences in stall behaviour for slipping and skidded stalls. It is likely that the about to become compulsory on-aircraft UPRT (from 2018) for commercial pilots includes actually flying these, but the Rule Making Group haven't issued this detailed advice yet (expected Q1 2017; IMHO this should definitely be included, and absolutely is as part of Ultimate High's UPRT programme).

This is potentially just as big an issue for GA, which has generated a fair amount of discussion in our instructor crewroom, especially given the dangers associated with using rudder to assist the turn when being blown through Final from Base leg at a high angle of attack. It's not part of the PPL flying syllabus, and the normally 'dynamic' nature of the event means that students not taught on aerobatic aircraft are unlikely to have seen it.

So we're interested. Have YOU had out of balance stalls demonstrated? Do you know what happens when you stall in a sideslip versus stalling in a skidded turn? Are you aware of the dangers associated with using rudder to 'assist' the turn onto Final when you're slow and/or have a high angle of attack?

[Maxthelion]

I'm not a commercial pilot, so I'm not really the right audience, but I do think there isn't enough training on the dangers of skidding the turn to final. I have been terrified by the handling pilot at least once when witnessing him rudder us around a final turn at a height of less than 400'.

Funnily enough, although I fly aeros, and have had training both dual and solo on skidding & incipient spins I don't think I've stalled an aircraft that was slipping since my glider days, and that was very benign. It was solo in a K13 and I had full rudder, full opposite aileron and full aft stick and was just descending in a straight line with lots of rumbling but otherwise very stable. I forget whether I had the brakes out.

I might try it next time out.

[Flyin'Dutch']

@FG - only in gliders

[Josh]

It was demonstrated at altitude in a circuit scenario in a Great Lakes as part of my initial aerobatic course at the exceptional Chandler Air Service in Arizona. They were allowed to develop to a full departure to illustrate the behaviour of the aircraft prior to the departure and also the violent nature of the departure and the height required to recover. I recall the feedback in terms of buffet and control response was distinct and the snap when the aircraft departed (especially when ruddering round the corner) was rapid and aggressive.

They also taught full power stalls in PA28s as part of their BFR package prior to hiring from them. I can't recall if slipping or skidding stalls were included I'm afraid. I haven't specifically covered those manoeuvres since despite flying occasional aeros sorties, where recovery has focused more on spins and unusual attitudes arising out of botched manoeuvres. I don't do solo aeros as I dint have been an appropriate share and lack the currency (of both Kinds!)

[PeteSpencer]

My only PPL instruction in the turn from base to final was:

' Watch yer airspeed'

Though, with due deference to my instructor if I was getting 'blown through' final approach, I was firmly warned not to 'haul it round' by over-tightening the turn, but either to fly through and re-intercept from the other side if room/time , or to go around.

Significance of this while low, slow and dirty-and especially if heavy with full tanks- (stall risk) was also stressed but we never practised it, at any altitude.

Peter

[flyguy]

Thanks for the comments so far. To clarify from Maxthelion's observation, this question is very much directed at GA pilots.

[ChrisRowland]

It was solo in a K13 and I had full rudder, full opposite aileron and full aft stick and was just descending in a straight line with lots of rumbling but otherwise very stable. I forget whether I had the brakes out.

Ka13 ailerons seem to keep working normally, even when the glider is stalled. I rather think that the tips aren't stalled at all.

Try FULL rudder, FULL back stick and neutral ailerons. That seems to be more effective at persuading it to spin.

Chris

[Rob P]

I can't recall doing so in the past.

Next time I can get myself a decent ceiling I'll check what happens with the RV. Technically it isn't cleared for 'intentional spinning', but presumably if I am practicing out of balance stalls and it happens, then that's not intentional.

Rob P

[fattony]

Have YOU had out of balance stalls demonstrated?

Never.

Do you know what happens when you stall in a sideslip versus stalling in a skidded turn?

No but I'm quite interested to find out now. I think I need to find an instructor to demonstrate this to me before I have a go myself.

[Dave W]

I have - I think 3 times well spread out over the years; in the Chandler Great Lakes like Josh, in a Robin 2160 and in something else I can't remember.

[davef77]

Yes, not by an instructor, but I have tried it myself, following previous discussions here.

Result: strong side-slip, easily controllable vs spin (also controllable, but slower to recover.)

[insink]

In Gliders there is a demo of spinning from an over ruddered, slow final turn which in the Puchacz and single seaters works a treat - obviously carried out at height!
as above - have flown slippingstall and if held long enough the glider (I did it in a k13) will eventually roll into a turn and may spin - depends on type tho height loss is huge. Ill try it next time i am in the puch or a single seater and see what the difference is....

[ChampChump]

In training, yes, gliders, motor glider and C150 (IIRC) and awareness was raised at an early stage.

[QSD]

The EASA ppl syllabus requires students to be taught stalling and recovery at the incipient spin stage (stall with excessive wing drop, about 45°).

I induce the wing drop by unbalancing the aircraft with a small amount of rudder as the aircraft stalls, so all my students experience out of balance stalling.

An out of balance stall during a turn is a different kettle of fish and highly likely to result in a spin. I would not routinely demonstrate or teach that.

Hasn't the base to final turn stall largely been eliminated as a cause of accidents nowadays?

[Joe Dell]

My own aircraft starts shaking like a wet dog. Impossible to ignore. Runs out of rudder before aileron. That's in a slipping stall. Turns into a shaking mush.
Not tried skidding. Won't try skidding. That's spin country.