Slip - I am led to believe that they were added to the Pushpak to degrade the roll rate as a couple of Indian Air Force instructors had been caught rolling them.
A lot bloody braver than me, those guys
On rebuild we applied to the PFA to not fit them so G-AVPO does not sport them any more. Yes the roll rate is better but it is hardly cosmic.
I still have them in my hangar if anyone needs them.
Stik