Bad wing drop during stall recovery practice.

[Hudson]

During practice on stall recoveries, one wing persistently drops quite startingly despite the stall entry and recovery being text book technique. This appears to be quite common in some Cessna singles.
It may be a rigging problem.

As this problem has serious ramifications if a student holds off too high during landing, should the defect be logged in the maintenance document? If so, would it be correct to say that the aircraft is strictly Un-airworthy until the defect is investigated and rectified? And should therefore the maintenance document be annotated "Aircraft un-airworthy" in order to prevent someone else accepting the aircraft before rectification?

Or do you just say "Stuff it - all Cessnas drop a wing during stall practice"- and leave it to the next pilot to worry about?

Keep in mind that the certification flight test parameters allow only a wing drop of maximum of fifteen degrees of roll during stall certification tests.

[Kermit 180]

I have also noticed that one of our Cessna 152's at our school always has a stronger tendancy to wingdrop than others. I believe this to be due to rigging. Intersted to see what others think about the ramifications of such a tendancy.

Kermie

[A and C]

The flap rigging is a good place to start looking however if it is an old aircraft the chances are that it is slightly bent from years of abuse and the flaps are rigged that way to mask a bigger problem.

Enyway a good wing drop is an interesting way to start teaching spin recoverys.

[Hudson]

So what I read so far is that nobody would snag a bad wing drop. Just leave it to some poor student to cop it while solo...

[ 03 August 2001: Message edited by: Hudson ]

[John Farley]

Hi Hudson

Your points about the need to look after the solo student are of course very valid and I’m sure most would agree with you.

Going back to your comment re certification limits, this does raise the issue of how certification stalls are carried out. As I guess you are aware, they tend to produce more benign handling as the speed is only reduced very slowly (1 to 2 kts per sec max). No attempt is made to hold height with all effort put into the most gradual change of speed so when a symptom happens (be it wing drop or anything else for that matter) you are able to check it at once by a little forward movement.

The problem with a student who accidentally stalls is that he may be loosing speed quite quickly (or increasing AOA fast by pulling) and so pitch himself much deeper into the stall before any recovery action takes effect. In which case you may more easily get the behaviour you describe.

My inclination would be to snag the aircraft for a rigging and/or CG check, or restrict it to dual only, if it does not calm down with a slow approach to the stall where the ball is kept fairly well centred.

JF

[ShyTorque]

I have put this out before but it is relevant so here goes:

Some years ago (28!) I was asked to enter and recover from a fully developed spin during a pre-GFT revision flight in a Cessna 150 new to the flying club I was with.

During a standard entry the aircraft did something very strange and we finished up in an inverted spin. The prop slowed right down and stopped. The instructor asked me how I was going to recover and I shouted (or maybe squeaked!) that I would pull back on the yoke instead of pushing. He nodded, I recovered, the engine started itself during the recovery and we flew straight and level for a good while as we recovered our composure!

The instructor later flew the aircraft again with one of his colleagues and the same thing happened again.

Some fairly serious rigging discrepancies were later found between the two wings.

I certainly think a serious wing drop should certainly be investigated.

:eek:

[hdaae]

If this tendency is voilent it should be looked into.

Ive flown with quite a few pre private students, and have only had one that froze repeatedly during stallrecovery when one of the wings dropped. Ofcourse, when the instructor are around to correct the stallrecovery its all fine, but one wrong correction during a soloflight might be the last one ...and thats one too many.

This student REPEATEDLY applied ailron away from drop and yoke back INSTINCTIVLY, which forced the plane into a spin. This paralyzed the student even more, and froze him with his faulty control application.
This presisted even after going thru the aerodynamics of a stall/spin and recovery procedures.

This was a student that already had his soloendorsement from another CFI, which makes me think he were lucky to still be alive, considering his inability to recover.

It took several demostrations by me in the plane, using normal stall recoveries and also intentional faulty recoveries to show him the aerodynamics applied in real life.

My point is, leave such a plane with a flaw, a student/private pilot with a INTENSE reaction to faulty stalls/spins and you have a potentionally leathal combination.

[John Farley]

Skybug

Your post raises a very valid side issue, namely, when a student has a serious problem such as you describe perhaps that individual should be kindly and sympathetically advised to call it a day, at least with respect to solo flying.

The other viewpoint is that with much good instruction they will overcome their problems in time. In which case fine, but can we be sure the problem will not recur in the future when under stress or when out of practice?

Perhaps the topic is worth a new thread. BTW I don’t have any answers.

[pesket]

hello,
I would snag it. Happened to me a few years ago, during a maintenance test flight one wing would drop significantly during the recovery. there was no tension in the cross wires inside one wing and it was warping when loading, that was a 150 by the way.

[hdaae]

Well, the student in question eventually figured out the stall recoveries, but part of his problem were stubborness. He had made up his mind about pretty much every aspect of flying, and had well over 50 hours when I started flying with him. He expected to be signed off for the flight check after a couple of flights, but I found his knowledge and procedures to be lacking, which, I guess, we can partly blame on the last CFI he had. I usually dont like to point fingers at people, but aviation isnt very forgiving, and sending off a student on solo without being proficient on stallrecoveries are nothing short of recklessness on the CFIs part.

As far as how to deal with it. After sitting thinking about who I have flown with a flight with a young girl came to mind. She were a collegues student, and he were at loss as far as what to do with her concerning stall recovery. I flew with her and she were shivering and sweating as soon as she heard the stall warning. She refused me to demostrate a stall, and the times I continued to hold back the yoke, SHE pushed the yoke forward, stopping the approach to stall. She did fine on all the other manuvers, so her intense apprehensiveness towards stalls (basically it all came down to being scared of spins and the notion that the plane would spin. Spins are not part of the Private training in USA, sadly)
We asked her if she wanted to become a pilot or not (in a nice way) and if so, she had to perform stalls by herself within manuver tolorances. She wanted to keep going, so we basically just showed her agrevated stalls/spins and how easy they are to recover from. This were ofcourse not part of the syllabus, but It had to be done, coz poor preformance with stalls are usually due to being scared off spins. After that spin flight her stall performance increased dramatically.

['I' in the sky]

Hudson, regarding your comment on the rammifications if the student holds off too high on landing.

Surely the wing drop only occurs if a full stall is allowed to develop. In the UK a great deal of emphasis is placed on stall avoidance training rather than purely recovering from full stalls.
ie learning to recognise the symptoms of the approaching stall and to initiate recovery at the first indications of the stall. If a student of mine allowed a full stall to develop in the circuit I would feel I had failed miserably.

[hdaae]

I agree, but a student should also have been given lots of practice on recovery from full stalls just in case he gets himself into one during a solo flight. Most likely he wont, but one should always cover all bases.

Better safe than sorry.

[Kermit 180]

Agreed, it is better to avoid a stall situation than to have to recover from one at low level, hence the practice at high level to see what the symptoms are and how to deal with them automatically.

I note that there is little opinion as to whether the wing-dropping Cessna should be re-rigged or grounded from use by students. The other side of the coin is that students are current with stalling, whereas a person who flies part time might hold a licnse but it may have been over a year since they last practiced any stalling.

Kermie :confused:

[Hudson]

Ï"in the Sky. Yes, I can see what you are getting at re landing stall. Back in the old days the RAAF had Wirraways (souped up Harvards) and these were quite vicious wing droppers if held off too high for landing. I have witnessed some classical wing drops resulting in wing tips bent upwards on ground contact.

It only required a touch of slip/skid via unnoticed slight rudder pressure during hold off to cause a wing to drop violently. Even in those days, stall practice emphasised recovery at first sign of stall - although there was no stall warning device.

I once sat spellbound in the front seat of the Wirraway when my own instructor (he flew Spitfires and Mustangs during the war) demoed a back-seat short field landing. He held off high and the wing dropped and crunched the wing tip up.

So with the C150 wing drop from a high round-out and possibly exacerbated by an extended float, the student with low hours may not react fast enough to a stall warning - particularly if the warning is via a reed which does not produce a clear audible sound.

The Cessna 150/2 series, like most trainers, are designed to be trouble free in stall behaviour and if a persistent troublesome wing drop is occurring to any one aircraft, then it should not be flown until the defect is looked at and rectified.
That was the point of this thread.

Too many instructors gaily laugh off bad wing drops as good clean fun and to be talked about in the crew room. A raw ab-initio student may not find it a laughing matter.