Hi Carfield,

Thanks for your response - yes... I would take a guess and agree that it might be ATC clearance, a backlog at HKG, or something wind/weather-related en-route.

I still find it a little strange that the delay is consistent over the past 7 or 8 days having not really happened earlier this month - the arrival times for CX251 were consistently 0520 to 0550am earlier this month and now they're consistently 0620am to 0630am... so I thought something specific might be up given that the flight is scheduled to land about 0540am. Indeed, the take-off delay (either non-existent, 2 minutes early, or 5 minutes late) seems disproportionate to the arrival delay (30 minutes to 50ish minutes late) particularly given the flight often arrives early into LHR and is exempt from the curfew.

CX251 is exempt from the LHR travel restrictions so it doesn't need to hang around Heathrow, so I doubt that is the reason for the delay of that flight (arrival time is 540am, before the 6am curfew finishes). However, yes... CX255 is bound by those curfews so that could have a part to play but I just guess it is something else.

If anybody has any other ideas then let us know I've been intentionally watching the arrival times as I'm on CX251 next week with a short(ish) connection once arrived into LHR.

Simon.