Question on Continued Airworthiness
This relates to a couple of Cessna aircraft I have flown that had Robertston STOL installations.
On application of 10 degrees or greater flap, the aircraft rolls left and will continue to roll inverted if the pilot does not intervene. The force required to roll wings level and hold them there is quite noticeable. It has to be held until landing.
The roll instability is there on takeoff as these aircraft call for 10 flaps on takeoff, but while it is noticeable once the wheels lift off, it does not require as much force at lower speeds. Same on approach.
It seems to me that the certificate of airworthiness is invalid when this situation exists as the aircraft does not meet the standards under which it was certified. Is that a correct assumption?