HIGH WINDS IN UK AND IRELAND
A plane can land in pretty much any wind speed although practically about 60 knots (110 kph) is the limit. But the wind has to be parallel to the runway more or less. However the problem arises when the wind is not 'down the runway', but has a crosswind component which means that the plane must “crab” into wind during approach and landing to avoid being blown off course.
The pilots do this all the time and are very good at it - no automatics here!The autopilots can only cope with winds up to about 25 knots (45 kph) so these approaches and landings are all carried out manually. If the runway is wet, then an additional problem arises - that of keeping the plane straight on the runway after touchdown since, just like a car, there is a tendency to skid on a wet surface. In these conditions the limit for landing is reduced further.
So the pilots have clearly defined limits for landing in terms of crosswind and the level of dampness on the runway. If the wind exceeds these limits then the plane cannot land, although it may make an 'approach to land' to see if the wind may drop at some point - the wind is never steady. If this is not successful the plane will “Go Around” - that is to say, apply full power and perform a manoeuvre similar to a normal takeoff except starting at some point on the approach.
Normally a second approach is permitted if the weather improves or is forecast to do so. This may also lead to a Go Around at which point the general idea is to divert to an airport with much better weather. A pilot will always have such an airport available or even a selection of airports with good weather. This is a requirement. As for fuel, when bad weather is forecast, the pilot will take extra fuel to allow for time spent at destination holding while waiting to land, and for the diversion.
Even in good weather a plane always departs with at least the following fuel loaded on board:
Fuel for taxi out to the runway
Fuel from Departure to Destination
Contingency Fuel - a percentage to allow for errors
Diversion Fuel - enough to fly to another airport
Reserve Fuel - half an hour of fuel still on board on landing.
In bad weather or when delays are expected EXTRA fuel is loaded.
See this clip of crosswind landings at Boeing in Seattle to see how easily the pilots cope with dramatic crosswinds.
The thing that the passenger notices the most is the turbulence associated with strong winds and gusts. This makes it uncomfortable on board but it is never dangerous. Download our ebook or audio book to find out more about turbulence.
John Leahy Flightcoach