Parallel Take-offs LHR ?
This evening at 19.00 I watched a PIA 777 float past coming out of LHR and then almost immediately (15secs) another 777 (Turkish ?) floated by. From my perspective they might have come off the same runway, but that is highly unlikely. So my question is, I'm aware of parallel landings at LHR, like when an A380 lands, often an A320 might parallel land to avoid the wake turbulence (assuming traffic flow allows), but I've never seen a parallel takeoff in many years of looking to the London skies, are they rare ?