[alistairSH]

That flight was an odd bird from the outset. It didn't have the range to make NY in a single go, so it stopped in Shannon Ireland to refuel, where passengers deplaned, went through US Preclearance, and rebounded. IIRC, the US->UK return was non-stop. So one leg was longer than normal. Ultimately, it was dying on it's own when COVID drove the final nail into the coffin.

[gib444]

It was bad for IRROPs too. You'd have to schlep over to Heathrow in case of any issues. And you have to explain to your boss why you picked the weird oddball flight over the reliable Heathrow with tons of flights to New York