However it is believed to be impractical to require that individual civilian display pilots specify a display sequence prior to the display and are then not allowed to vary it or modify it in any way later.
I agree Jacko, this rationale is nothing short of absurd. It actually encourages and promotes a culture of laissez faire and ad-hockery in display flying. A culture where it is absolutely fine for a pilot to vary his display if he feels like it ... and if the FDD gets grumpy, he can just blame the wind, cloud or time pressure!!! "Sorry Guv, I chucked in a few derry turns to save time which threw my display out a bit", or "I usually do a half-cuban early in my sequence to reaffirm my gate and local conditions before doing a loop, but to save time I canned the cuban."
Even a Plan B (most typically due to low cloud, e.g. a flat display) should be a written and practiced Plan B, and it
must also be in the hands of the FDD.
My plea to the CAA is this: getting this right does not need draconian regulations. What is needed is cool heads and plain common sense to fine-tune the regs for safer display flying, backed up by an unambiguous implementation policy.