I came back from Dublin on Air Lingus (A321) yesterday evening. We were crusing over London I believe when the plane shacked rather violently,but only once (like a rather strong turbulence).
The pilot made the following announcement: we just experienced a turbulence created by a plane flighing by rather closely.
Now my question:
I believe that planes flying on the same altitude have to be at least 50 km away from each other and about 1000 m altitude difference.
Lets suppose a plane flies at 900km/h (I know it is a bit slower, but makes maths easier...). It takes a plane about 1min to fly 15 km (flying at 900km/h), roughly 3 min for 50 km.
I believe that a 747 taking off prevents a small plane like an Airbus 320 from taking off or landing for about 2 min. I suppose that there are turbulences for about 2 min (simplifying as turbulences in the air are different then turbulences on the ground, am I right pilotes?).
So if it takes 3 min to fly 50 km and it takes 2 min for turbulences to disappear, does this mean that the other plane was at the most 30 km away from my plane? A smaller plane would have been closer, as it produces less turbulences and yet we could feel the turbulences.
Now the question, what is the age of the pilot? Just kidding the real question is: was this close? I am not sure about turbulences created by a plane flying by, but on a different altitude.