Originally Posted by
Mark in CA
Interestingly, the crew also mentioned that this issue was first reported on the way to LHR two flights earlier, and a decision was made then to defer the software update and continue to fly the aircraft to IAD. Apparently, this issue was not serious enough to ground the plane at LHR, and it was only at the crew's discretion at IAD to request the update; there was nothing requiring this.
I suspect there's more to this than meets the eye.
The aircraft in question sat on the ground at LHR for 3 days between its arrival from YVR on Wednesday and its departure to IAD on Saturday.