Oscillatory stalling

[NorthSouth]

Referred to in:
http://www.aaib.dft.gov.uk/publications/bulletins/march_2006/slingsby_t67c_firefly__g_fors.cfm

Anyone heard of it or know what it is? All the AAIB seem to have is a description from a student:
"maintaining the aircraft in a stalled condition whilst controlling any wing drop with rudder"
Seems fairly mundane to me - where does the "oscillatory" bit come in?

Since AAIB has asked the CAA to give advice to instructors on it they may have a hard time if no-one can define it!

NS

[EGBKFLYER]

Reading the whole report, I think the AAIB don't know what it is and are concluding that it was the FI's own term, since they refer to it being written in the student's logbook.

I believe the term refers to the 'nodding' motion that occurs in most small aircraft when in a fully developed stall - i.e. when you 'hold it in' to demo all the characteristics.

[Stampe]

I wondered just the same ,but in the past have put modern docile stalling trainers into as fully developed a stall as full aft elevator will provide and held it into the buffet.I,ve found the nose tends to pitch in an oscillatory fashion and student can be got to check any wing drop and maintain wings level with use of rudder .The older generation "hairy chested" trainers are much more prone to departing into a spin given that sort of treatment and their much more powerful elevators.I wonder if this was what the report was implying.Interesting if sad reading.

[NorthSouth]

That's what I read into it too, but given that the AAIB recommendation is "to ensure that oscillatory stalling is not included in flying exercises during ab initio flying training" it would suggest that they see no distinction between doing it in a Cessna 152 and doing it in a Harvard, which would make proper teaching of Ex.10B a lot harder and will only make students even more apprehensive about the whole topic.

NS

[nipper1]

It could be a reference to a rather lovely, if very simple, maneuver sometimes called a 'falling leaf'.

Start with an incipient spin and as the wing gets nicely dropped but before there is any significant yaw, keep the stick right back and smoothly apply full opposite rudder. The aircraft will pass through wings level, fully stalled and drop the opposite wing. The action can be repeated almost indefinitely until you run out of altitude. The aircraft rock (oscillates) from side to side and drops very much like a falling leaf.

The exercise is a very good way to get to know the aircraft you are flying and with practice (and a little rhythm) you can oscillate almost vertically downwards.

Too late an application of opposite rudder will probably lead to a full spin and for this reason the exercise should not be conducted unless the aircraft/pilot combination is cleared for spinning, at a safe height etc. etc..

I have no idea if the exercise is safe (or permitted) in all aerobatic types. I have completed it successfully in a Robin 2160A and my Tipsy Nipper.

[AerocatS2A]

It sounds a bit like a rudder excercise my instructor had me do in a Pitts. with partial power (about 1700 RPM or something), and the stick held fully back to maintain a stall, the pedals were used to keep the wings level. He called it a "parachute stall".

Seems like these guys needed to go through spin recovery before carrying out such a spin-likely manoeuvre.

[watty]

Does sound like a falling leaf 'nipper'

Seems a bit of a knee-jerk response from the CAA.

Useful excercise as the student can learn what their feet are for and how to prevent/control that 'wing drop.'

Never had any issues in my benign C150/172's (Canada, where spin recovery is mandatory for PPL). Always ensure you are safe in case a spin should develop.