London to Sydney: what the LHR to SYD corridor looks like
- Departure
- London Heathrow Airport, London, the United Kingdom
- Arrival
- Sydney Kingsford Smith Airport, Sydney, Australia
- Great-circle distance
- 17,020 km (9,190 nm)
- Typical airborne time
- 20h 17m
- Usual cruise levels
- FL320 to FL410
- Initial track
- northeast bound
Route overview
London Heathrow Airport (LHR) in London, the United Kingdom, to Sydney Kingsford Smith Airport (SYD) in Sydney, Australia, is a great-circle distance of 17,020 km, about 9,190 nautical miles. At typical jet cruise speeds, and with an allowance for climb, descent and approach, that works out to roughly 20h 17m of airborne time. The great-circle track leaves London northeast bound and spends most of the flight in equatorial air.
Crossing the Intertropical Convergence Zone
Along the way the track passes over the equator and high latitude airspace where the polar jet stream lives. Near the equator the track passes through the Intertropical Convergence Zone, a belt of tropical thunderstorm clusters. Convective cells are visible on the aircraft weather radar, so pilots steer around them well in advance. Bumps near the zone tend to be brief and localised, with smooth cruise on either side.
Cruise altitudes on this sector
Ultra long sectors begin cruise lower, often near FL320 because of the fuel load, and finish two or three step climbs higher, up to FL400 or FL410. Choice of level matters because turbulence is layered: a change of two or three thousand feet often puts the aircraft into calmer air, and that is one of the first adjustments a crew will request.
Seasonal pattern
The convergence zone shifts north and south with the seasons rather than disappearing, so time of day matters more than month. Morning departures cross before the largest cells build.
Flying this route with less worry
Turbulence on this corridor is a comfort issue rather than a safety one. Airliners are certified to handle loads well beyond anything the atmosphere produces here, crews are trained for it, and the seat belt sign is the tool that keeps the cabin settled. What this page adds is knowing in advance: the map and Calmness Score above use current WAFS forecast data for LHR to SYD, so you can see what to expect before you board.