Dutch Roll testing
Question for the house.
I'm doing a bit of work on some mods to a high wing twin-turboprop. The company schedules call up aileron-doublets as well as rudder doublets for DR tests. The type seems to have pretty standard characteristics - can anybody suggest any reason (other than perhaps some over-enthusiasm at some point) why somebody should do both tests? My experience is that the only time One schedules roll-doublets for DR investigation is when the aircraft has inter-linked roll and yaw mechanisms, and then I wouldn't conduct a rudder doublet.
G