A penny for your thoughts: The B206B-3 that I fly, has a diagram in the flight manual showing a tail wind from the 3-7 o'clock position as being unfavourable w.r.t tail rotor control effectiveness (TRCE). Without getting bogged down in the interplay of main rotor induced flow and blade tip vortices on the tail rotor in certain cross wind conditions, looking at a basic 90 deg X wind condition.
Considering a cross wind from 3 o'clock, this will basically increase the induced flow the tail rotor generates when creating thrust to overcome MG torque. This increased induced flow can reach a point where the tail rotor is unable to overcome it, and therefore a loss of TRCE is felt.
However there is the other school of thought which goes with vortex ring state. Again simply put, a cross wind from the 9 o'clock position, will oppose the induced flow through the tail rotor. This could reach critical a point, where the induced flow through the tail rotor is matched by the crosswind, holding the tail rotor blade tip vortices and the disturbed airflow at the blade roots, on the tail rotor disc, and as with the main rotor, a vortex ring state condition exists, causing a loss of TRCE.
Should the flight manual address this? which one of the two conditions mentioned above is more common? It seems to me there is no clear cut answer? Fortunately in my experience, the effect of cross wind on the lateral weathercock stability of the 206, normally will alert you to a pending problem before you go into a full blown loss of TRCE, as you realise you are putting Fred Astaire to shame with your dancing feet on the pedals, followed by alarming fluctuations of the torque gauge!
