Deliberately forced wing drop stalling in GFPT test

[A37575]

The ailerons should be neutral until control is regained, then level the wings.

I believe most training aircraft designed in the past 25 years or more are designed so that the ailerons are effective beyond the stall. That being so, while you are correct in saying sufficient rudder should be applied to prevent further yaw induced by the down going wing, the recovery with forward stick to reduce the angle of attack is instantaneous allowing the ailerons to be used to level the wings. There is no case for keeping the ailerons neutral during the initial prevention of further yaw because recovery is instantaneous with the ailerons effective by design below the stall.

[jas24zzk]

Interesting discussion...............................Aerodynamics is my favourite topic.

I haven't figured out how to quote people on this forum yet....


A373XX (lets call him Anumbers) asks if I meant by picking up a wing with rudder. YES that is exactly what I meant.


Seavenom, says regain control via Rudder then use ailerons as required Later. Not sure I 100% agree, but every situation is different.

Anumbers goes on to state that most training aircraft designed in the last 25 years are designed to have full aileron authority at speeds much lower than the stall. This corelates very well with the Seminole, that is Vmca is below the stall making it docile.

The last post by Anumbers, fails to recognise what people are training in today. Many are doing their initials in in RAA types, ie Slabaroo's and tecnams.

These types will not forgive sloppy rudder behaviour. A warrior 2 (ie any PA28-xx1) will forgive you for being rudder lazy. A Jab or a Tec will not, any day of the week!.


I Listed the Grumman Trainer (AA-1B) in my list of unforgiving aircraft based on experience. In the same group you can also add the AA-1C (Lynx) and any hershey bar winged Cherokee type (PA-28 PA-32)

The Grummans demonstrate the technique the most violently of any type i have flown. A warrior 2 (pa28-xx1 series) will let you dial in as much aileron as you want to and correct itself. The Grummans, and tecnams if you you dial in the aileron WILL demonstrate classic aileron induced stall and roll in the opposite direction.

I was trained by the late Mike Valentine, and his training on rudder use has saved my life at least twice!

1. VH-GIF (pilatus b4 glider 15m span, approved aero + flick). Aircraft had just come out of maintenance. Owner did a 20 min test flight to aircheck and push the envelope. He signed it off and handed to me. Somewhere approx the 3 hour 20 time frame of my flight the aileron circuit suffered a catastrophic failure. I had the option of popping the canopy and climbing out. I had height on my side so I decided to experiment and see what i could do. End result I used rudder, and got it back on the ground safely....this aircraft is still flying today.

2. VH-APX (grumman aa-1c lynx). I was asked by the aicraft owner to spend some time ICUSing a guy to have him added to the insurance policy, insurer was happy as i had more time on type than the owner. The pilot in question, almost all of his time was on PA28-xx1's. We had done some flying about the region landing at several local strips that the pilot had never been to and i was feeling reasonably comfortable with his handling of the A/C. We were making our final appr to our home field when the **** hit the fan. He was on the money for speed, but conditions at best were blustery with a right to left cosswind. 10 feet off the deck we copped a gust. that rolled the A/C hard left. He applied FULL right aileron, and it continued rolling left. At this point I took over (ground observers say the wingtip missed the grass by less than a foot) When I took over I found the yoke full right and immediatly applied full right rudder, i'm not even sure the ICUS pilot got the oppurtunity to fully relinquish control to me as my my control inputs were savage enough that i still believe that I actually stalled the right wing. It is a classic case ofadding aileron on a hershey bar WILL deepen the stall for the wing in question and the only way you will fix it is with a bootful of rudder in the opposite direction.


So yes i am an advocate of rudder before aileron

Cheers
Jas

[A37575]

I had height on my side so I decided to experiment and see what i could do. End result I used rudder, and got it back on the ground safely....this aircraft is still flying today.

Well done that man. So rudders are all the go in this discussion even to the point of deliberately skidding the rudder until the faster going wing develops so much lift that eventually after air sickness from excessive skidding subsides the aircraft becomes wings level and NOW the pilot can dare to use aileron

Forget the rudder hero. Do you know you can also use the doors to get on the ground safely? In the Cessna 152/172 and all those with two doors, simply open one door a little bit and the aircraft will do a well coordinated turn. Of course you need to know which door to open...

[jas24zzk]

Well done that man. So rudders are all the go in this discussion even to the point of deliberately skidding the rudder until the faster going wing develops so much lift that eventually after air sickness from excessive skidding subsides the aircraft becomes wings level and NOW the pilot can dare to use aileron

Thats not what I am saying and you know it. Uncommanded Roll can be considered a stall/spin type movement, esp when slow, and should be given even more respect when you are almost on the deck.

If you read the Grumman example I gave, it is a classic case of aileron deepening the wing stall (did you miss that lesson at ground school???) At that point in time, the HELL with how anyones guts felt, I had no inclination to go cartwheeling down YCEM's lovely all weather strip.

Cheers
Jas

[gkpilot]

droping wing

wow, how long have u been flying for???if you pick up with aeleron it will be worse
cheers happy stalling

[APMR]

Most current trainers waffle in a nose up attitude at the stall and are practically impossible to stall.

Point of order. Those aircraft are ALREADY stalled.

in large passenger jets even 35,000 ft may not be enough recovery altitude of course.......

I think Mimpe is referring to Air France 447, the Airbus 330 that entered the stall near FL400 over the south Atlantic ocean. The aircraft remained stalled all the way down and brought the deaths of all 228 persons on board.

The FDR revealed that there were two "stall recovery-like" actions on the controls but they were insufficient to break the stall.

The final report is not out yet but the ICAO has already stated that it intends recommending to member countries that they review how stall recovery is taught.

It appears that the recovery technique being used by the crew was based around achieving the minimum height loss.

I believe that, in Australia, minimum height loss is one of the requirements of a stall recovery.

[Oktas8]

It's interesting that CASA defines a stall as an aerobatic (acrobatic?) manoeuvre.

It certainly explains why CASA think it is unsafe to stall below 3000'. I agree that it's a reasonable height for solo student practise, no argument there. But for an intentional stall by an experienced pilot? Bizarre. I stall all the time at 1 foot height in some aircraft. Perhaps I should turn in my license?

I prefer the more traditional view, that an aerobatic manoeuvre is one where the aircraft is rolled to beyond 90 degrees (60 in some countries), or pitched beyond about 30 degrees up or down (that number varies too). A stall is just so benign in light aircraft that to call it a acrobatic manoeuvre is to portray the wrong impression altogether.

[MakeItHappenCaptain]

Although Australian instructors teach the standard recovery is using rudder to arrest wing drop with ailerons neutral, there are definitely aircraft that utilise positive aileron inputs during the recovery.

Research your flight manuals, people.

I completed an endorsement at an overseas factory with the factory test pilot (who had everything from F104, F15/16/18 and Tornados to Airbuses on his licence - read as knows his stuff). When I quizzed him on the AFM technique not utilising ailerons neutral (wrt spinning) he was adament the only aircraft he had flown that did not use ailerons to recover was the F4 Phantom.

Food for thought.

ps, Oktas8, Aust defines aerobatic as greater than 60deg AoB,
CAR 155(2) specifically states that straight and steady stalls where <60 AoB is flown are NOT aerobatic.
Otherwise, students would need an aeros entry in their logbook to practise them.

[Tee Emm]

It's interesting that CASA defines a stall as an aerobatic (acrobatic?) manoeuvre.

In what publication is that stated?

[Lasiorhinus]

Oktas,

CAR 155 (2) For the purposes of subregulation (1), straight and steady stalls or turns in which the angle of bank does not exceed 60 degrees shall be deemed not to be acrobatic flight.

Check your facts before posting please.

[QJB]

I think that the way stalling is taught in flying schools is on the whole a load of rubbish. So much so that students learn to fear stalling the aircraft, spin training is no longer mandatory according to the CPL(A) syllabus

I remember my first lesson of stalling and the instructor's words: see what we need to stall, a nose high attitude, low airspeed, sloppy controls, buffeting. Then the stall and PUSH! Lose about 500 feet in the recovery. Be fearful of wing-drops and only ever use the rudder. What a load of rubbish.

So many OWTs.

Low airspeed will not make you stall
Large angle of bank will not make you stall
A high nose attitude will not make you stall

I would recommend anyone that is fearful of stalling complete an aerobatics course or EMT. Best money I have ever spent.

My 2 cents,

J

[MikeTangoEcho]

QJB,

It is a whole load of rubbish IF it's taught like that. What your instructor should have made clear is that those were the symptoms of an approaching stall, not the stall itself. Probably should've briefed on slow/high speed stalls as well.

I agree with you on the aerobatics course to overcome the fear of stalling, definitely.

[Oktas8]

Thanks to those people who have pointed out that CASA doesn't define stalling as aerobatic. "check your facts before posting", indeed.

Tee Emm: perhaps you have forgotten having written this:

Stalling is not an aerobatic manoeuvre and the authors of the CASA Flight Instructor Manual, were living in the past when they mandated practice stalling as an aerobatic manoeuvre.

I was responding to the OP and perhaps the first respondent, both of whom made claims about the FIM and about stalling, implying that it states stalling is an aerobatic manoeuvre, or that the FIM said that in the past. Is the FIM written by CASA? I think so. Does the FIM actually say that? Wouldn't have a clue. Don't care. He said it, not me.

Ho hum. Yet another reason not to post on Pprune. Respond to a post, get shot down. By three people no less.

Oh well, may as well be hung for a sheep as for a lamb:

Most current trainers waffle in a nose up attitude at the stall and are practically impossible to stall.

Perhaps you don't know the symptoms of a stall? They are buffet, nose drop, sink and wing drop (the last one only if flying out of balance at the point of the stall). Apart from canard-winged aircraft, you'll get at least two and usually three or four of these symptoms.

But 3000' is a little restrictive, we can all agree on that.

[MakeItHappenCaptain]

Don't think I would've classified my response as "shooting you down".
You made a comment that was incorrect and I merely referred to the Regs.
Don't stress, I've done it too.

Agreed, there are many people who live on this site purely to debate logical arguments, or so it seems (and not referring to Lazo or TM). Threads written on the negativity in the past, but don't be discouraged.

[Tinstaafl]

Although Australian instructors teach the standard recovery is using rudder to arrest wing drop with ailerons neutral...

I must disagree with this comment. 'Arrest wing drop with rudder' is not a standard technique and no instructor working for me was allowed teach this. Prevent yaw with rudder, however...




Edited to correct an incorrectly quoted word, as pointed out in a following comment. My point is the same, however. Rudder is not used to control roll but to control yaw. If the wing drops, it drops. So what if one wing is low, as long as yaw can be controlled. After the stall is recovered then roll the aircraft to wings level if need be.

[MakeItHappenCaptain]

I didn't say prevent, I said arrest.

[Ando1Bar]

Jeez some rubbish gets posted on these forums.

you'll get at least two and usually three or four of these symptoms

if you pick up with aeleron it will be worse

asks if I meant by picking up a wing with rudder. YES that is exactly what I meant.

Makes it hard for the less experienced or knowledgeable pilots to know what the good information in the thread is.

I feel better now for having a short rant...

[Oktas8]

Which aircraft do you have in mind Ando1bar that does not exhibit the symptoms of the stall I listed? Just curious.

[Ando1Bar]

Your typical C172 for one. The high wing vs low elevator didn't always produce buffeting. The coupling action didn't always cause the nose to pitch down (more to do with releasing back pressure with a now out of trim elevator). A wing drop isn't easy to produce, requiring significant yaw to get it going (some particularly poorly rigged were very easy though), usually created by power and the subsequent slipstream effect. A rate of descent - yes, you are right with that one.

It's misleading to say you WILL get a combination of those things. You MAY get some of those things, but "usually three of four" is a gross exaggeration for many types.

Gets back to knowing your particular aircraft and understanding aerodynamics.

[Oktas8]

Thanks for the answer Ando1bar.

The C172 does actually exhibit nose drop and buffet and sink. The nose drop is minor with power off, and can be likened to a "nodding dog" effect (those funny nodding dog models people have on the parcel shelves of their cars). The nose drops, comes up, drops, comes up, and so on, as long as the control column is held aft. The higher the power setting, the more pronounced the drop. This kind of nose drop is a very strong indicator of a stall because it is constant across almost all types.

This kind of nose drop is very useful in a trainer. Mainly, it teaches effective awareness of the full stall in a very conventional aircraft. However it also helps instil precise attitude awareness, in the stalled regime as well as normal flight.

If your Cessna doesn't drop the nose at all at the stall, either it is loaded outside the manufacturer's approved CG range, or it is an old one with stretched or dodgy elevator cables such that it is actually incapable of stalling (flew one like that once ), or you simply haven't stalled.

Back to the symptoms. Sink is obvious. Buffet is not obvious if flap is down. I will give you that. It exists, but is well masked by the normal vibration associated with the flaps being extended. As you say the airframe layout has a lot to do with that. I taught buffet recognition by finding smooth air, and very gradually decelerating through the relevant speed range, in trim, while saying "follow through, and tell me when you can feel buffet." Most people could recognise it for themselves without me having to prompt.

Wing drop is minor compared to other types. It is not necessary to apply incorrect rudder input. (Oh my goodness please don't do that in front of a student pilot.) 1600 rpm, approach flap, and a relaxation of the rudder will often, not always, give some degree of wing drop.

So there are two definite symptoms, a third which is well masked with flaps down, and the fourth of course may or may not occur depending on configuration power and balance.

Please note that these are stall symptoms, not symptoms of an incipient stall or impending stall. If you don't believe my description of the nose drop in particular, try holding the control column aft against the stops in the stall. I have found many pilots are unwilling to do this in a Cessna, and as a result never quite completely stall.