That doesn't negate the fact that until the permanent FIS is built, there is the potential for three aircraft arriving from Europe at close to the same time, I doubt DE or one of the Icelandic carriers will sit down with BA and discuss gate usage. At least Iceland can be served with a narrowbody.
I thought the reason they put an additional jetbridge at the FIS facility was to accommodate more than one flight at a time? Certainly, two widebody flights could not fit in the space, but a narrowbody like FI could probably along with the BA flight.
Regardless, this only magnifies the fact that BNA needs to get going on the permanent IAB at once. It is a shame they couldn't do that first, but I guess D was more important.
There's no simple way to do both at the same time. It's already going to be a hassle when TSA moved back to the old way of screening. D really has to be built before the IAB started. You just don't replace flights using 6 gates that easily. Should they have started earlier? Sure, but they didn't. So it's a fact of life for the next 5-6 years, BNA's terminal is going to be a mess.
It wouldn't have been simple, and it would have created some headaches and some creative shifting around, but the central terminal/permanent IAB should have come first. Unlike it's peer airports (RDU, AUS, CVG, IND, etc), BNA does not have any proper widebody-capable gates, and until that issue is addressed, it will hold the airport back from further international flight growth. The permanent IAB will address that issue, creating gates that can handle aircraft up to the 747 if necessary, but it will be at least 5 years before they come online.
Yes, it would have resulted in six gates being lost for up to 3 years, but some of the gates are used by carriers that have only 1-2 flights a day at most, or less than daily service (carriers like F9, G4, AS, WS, etc). They could have shared for a few years.
Anyway, it doesn't matter. I think the problem is BNA just underestimated the growth it would experience and now they are scrambling to catch up, nothing more or less. I'd rather the airport board be somewhat more conservative and have the growth exceed expectations rather than overly ambitious and having the growth not meet expectations. IMO, there is more that will be needed than what BNA Vision covers, but we'll see where things stand after the entire project is completed.