****e
You are indeed correct. You must always have a Plan 'B'.......and maybe C and D too.
Given that in the real world the job simply has to get done sometimes (at least that's how it sometimes feels!), pushing on with Plan A in deteriorating conditions is quite acceptable to a point, provided one can recognise when to revert to Plan B.
As regards the Twin-Squirrel, the flight profile adopted after the initial orbit and descent over the haulage yard looks to me like a classic case of 'Direct to'. I don't think I would have attempted this if I was relying on a map, stopwatch and compass - though I may have with a good Moving Map.
JJ