Thanks AerocatS2A. I was maintaining altitude in my scenario and I got the winds wrong way round. I thought I may have been mistaking the headwind for the increasing tailwind. That was exactly what I was referring to. Does this scenario play out often enough that planes need to leave their assigned altitude when a strong tailwind is heaving them along the north atlantic? I know that this bit of airspace in particular is very controlled in procedures. Eventually you need to stop descending so what if the tailwinds are so strong that you can not maintain any assigned altitude? Maybe this doesn't really happen so much? Just curious.
Cheers,
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