Stalling lesson from a qualeval
 

I've been out of town for a couple of days evaluating a rather pretty little 2-seater "somewhere in central Europe". Many interesting things about it, but one or two with flight test lessons I've learned, one of which is worth sharing without (I hope) causing offence to anybody.

Stalling
Armed with a careful read-through of the POH I was expecting a benign stall and stalling speed around 50IAS, which was just on the certification limit. I actually got 45IAS and a rather vicious wing drop / possible incipient autorotation that was not mentioned in the data I'd reviewed and seemed to rather frighten the safety pilot (who also happened to be the designer).

On subsequent inquiry, the certification standard (a local code based upon the Canadian TP10141E requirements) required a stalling speed below 65kphCAS (which as it happens was 50 IAS). So, the local TPs slowed the aircraft down to about 64.9kphCAS, didn't hit a handling problem and therefore declared the stall speed as 65kphCAS with no wing drop. I've a bad feeling that I may have been the first person to take it to the para201 handling stall, arguably under circumstances I wouldn't normally wish to, but at least it had a recovery parachute fitted. (Interestingly they sell it, as a trainer, with a placarded limitation prohibiting deliberate stalling.)

The lesson I take from this is to beware "certification fudges" where excuses have been made by somebody, somewhere, for not properly exploring the handling envelope. (And to ask more searching questions before flying). I confess that it had not previously occurred to me that anybody would in an aircraft with no stall protection system do other than take an aircraft during certification testing to the full handling stall - but there you go, I've learned something.


Just thought I'd mention it.

G

At the risk of soundling like an advertisement for test pilot training, did the person who had done the 'certification' flying have any flight test training?
Had they checked with any authority that their way of doing things was OK?
How interesting. And thanks.

It doesn't appear that anybody in that particular country had received formal TP training - they can't afford the western variety and under it's previous Eastern management TP training didn't really exist. They have a local authority (and by the standard of smaller country Airworthiness Authorities quite a good one) but the training and experience of authority staff was inevitably similar to that of the company staff.

I did point these chaps at standard UK and US textbooks and offered some teaching material from my own archives but, more's the pity, I don't think that they could afford the excellent NTPS or any equivalent product.

G