Five things to k now about flying the jet stream

Four hours and 56 minutes is all the time it took for British Airways Flight 112 to fly from New York’s JFK International Airport to London Heathrow early Sunday. The flight broke the previous transatlantic record of 5 hours and 13 minutes between New York and London. Why, and how?

1 Fasten your seatbelts

A jet stream of 420 km/ h turbocharged the transatlantic flight, which departed New York at 6: 20 p. m. and landed in London at 4: 43 a. m. Sunday, nearly two hours ahead of schedule.

2 Pop some Gravol

The jet stream is the zone of strong winds some 10,000 metres in the atmosphere, along which storms track. Many commercial aircraft hitch a ride along the jet stream to give themselves a speed boost. But jet streams are a leading cause of air turbulence. While flying through the core of a jet stream can often be smooth, entering and exiting these zones of extreme winds can be rough, as considerable amounts of wind shear — winds differing in speed and/or direction with height — is usually present.

3 Maybe just keep going East

In winter, the North Atlantic jet stream is at its most powerful, slingshotting flights eastward across the Atlantic — and slowing aircraft moving to the west, often adding more than an hour of flying time to the return trip, and occasionally even a refuelling stop.

4 The big boom theory

As it shot across the Atlantic, the Boeing 747- 400 jet reached a top ground speed of 1,325 km/ h. However, the jet did not actually break the sound barrier, since that is measured by its airspeed — the speed of the plane relative to the air through which it is travelling. On the flight deck Saturday night, the pilots likely saw its airspeed hover close to its typical maximum cruising speed of Mach 0.855, or about 1,050 km/ h. Supersonic commercial aircraft, specifically the British Airways Concorde, have crossed the Atlantic in far less time, with its record still standing at 2 hours and 53 minutes.

5 Windswept upon arrival

The jet stream that powered the flight across the Atlantic gained such strength due to the pressure difference between an unusually intense zone of low pressure east of Greenland and a high pressure zone to the south. ( High- speed winds are the result of strong pressure differences.)