LeSving plenty of types are also “unrecoverable” from flat spins. This is due to rudder blanking, down elevator increases the blanking which in turn maintains the high rotational nature of a flat spin.
A recent (2009) training accident in a Seminole in Croatia being potential addition to the dozens (hundreds?) of flat spins resulting from Vmc demos at Vmc – schools should demonstrate at Vsse.
Aerobatic types will be specifically permitted in their AFM for flat spins, some aerobatic types having the maneouvre prohibited due to rudder blanking.
The existence of a deep stall, in particular on T-tail aircraft seemed to be a risk that was recognized by the Fokker aircraft company. During certification of the Fokker-100, rockets were mounted aft. Entering a deep stall on purpose and then firing them to push the plane out of that state.. There were two rockets. One to be fired and the other to be used in case the first failed. The pilots apparently had different ideas. They fired both at the same time, reasoning that if one rocket would not be enough to get them out, the other would serve no purpose either when fired in sequence 
After a horrific plunge in the stall, giving time for the on-board measurement equipment to measure the aerodynamic behavior, they fired both rockets and the plane recovered. A colleague of mine (doing the measurements) described the situation in the cockpit after the manoeuvre as ‘quiet for 30 seconds’, and then the captain just said ’let’s call it a day’
Aerobatic types will be specifically permitted in their AFM for flat spins, some aerobatic types having the maneouvre prohibited due to rudder blanking.
I thought blanking of the rudder was one of the main techniques of a real flat spin. A real flat spin is a controlled maneuver where the gyroscopic force of the propeller accelerates the rotation, and is done with full power. The tail fin and rudder will slow the spin in this configuration, and blanking them is done with for instance stick fwd. A normal spin in a modern aerobatic aircraft looks like a (semi) flat spin due to the huge control surfaces and control angles, but this is not a real flat spin, since it can be done with power off.
What does “active” sidestick mean? That the right hand one will move if the left hand one is moved, and vice versa?
That sort of thing would have removed one of the holes in the cheese on AF447. However, where CRM broke down to zero, there will be other ones left.
One can see why opinion is polarised on the Airbus v. Boeing way of doing this… I do think the two types achieve similar levels of safety via two different routes 
American SOPs emphasise a three-way exchange of control: you have control-I have control-you have control, where the exchange of control is verified and confirmed by both crew members. Europe the convention appears to be only two way. Not sure if this simple practice would have been another line of defence for AF447, but perhaps adopting the American approach would have helped – just saying.
RobertL18C wrote:
Not sure if this simple practice would have been another line of defence for AF447, but perhaps adopting the American approach would have helped – just saying.
MedEwok wrote:
Can three experienced pilots really ignore and disregard a STALL warning so persistently?
Well, the Airbus ‘logic’ suppresses that warning (or at least did until AF447, don’t know if that’s been changed) below 60kts. IIRC from the accident report, it came on intermittently, they seemed to think they were out of it, when in fact, they were in a deep stall. While CRM certainly had completely broken down on that flight, the Airbus systems logic didn’t help. I venture to say, it was an integral part of the disaster.
