Last Friday ( the 27th) we had a 9 am flight out of SEA, and as we taxied to the runway I noticed a BA 747 sitting off the north end of the runways in the " long term parking" area, nowhere near the gates. This seemed odd, since the arriving BA 49 wasn't due to land until around 4 pm, and departure of BA 747 is scheduled for around 7 pm.

I just looked on Flightaware and see that there was no BA 48 ( SEA to LHR) on Sept. 26, and BA 49 (LHR to SEA) was canceled on Sept. 27.. presumably because the plane needed was sitting in Seattle!

Does anyone know what was going on? Does BA have so few 747s that they could not find another to serve that route? If the BA 49 plane that arrived in Seattle on the 26th could not make the return flight to LHR that day, I can see how they would not have a substitute plane for Seattle to LHR. But could they not have pulled in a 777 or something to fly BA 49 on the 27th rather than canceling the flight?