This was a planned power test that went horribly wrong!! The power to the Scottish Domestic operations room (and probably the Shanwick Oceanic Ops room) was completely lost, which resulted in loss of all main systems for about twenty minutes.
Only thing working was the secondary standby R/T system, which saved the day. Radar, phones, R/T and standby R/T all out for the duration. Not the most relaxing place to be at 2115 last night!!
Do airlines ever do power systems tests on aircraft when they are in flight with fare-paying passengers onboard????? - I think not!!!
Wings level, Ball in the puddle!