Storm Eunice is causing disruption at Heathrow and other airports in the South East as pilots struggle to land aircraft in high winds.
The Met Office has issued a red weather warning due to high winds for London and the South East until 5pm today, with Amber warnings continuing until tonight.
As of midday, British Airways has cancelled 43 departures from Heathrow, with more likely to follow.
What happens to flights when it’s too windy?
There are safety limits on when aircraft are allowed to take off and land during windy periods. These limits depend on the aircraft type, runway direction and general weather conditions.
A long haul captain with a European airline I spoke to said:
“Wind speed limits are primarily based on crosswind, which is wind that blows perpendicular to the runway. And it’s slightly different between aircraft types, and different airlines may apply lower limits than others, but not higher than manufacturers’ limits.
The runway direction at Heathrow is about 270 degrees, the wind direction today is forecast to be about 280 degrees, so there won’t be much of a crosswind. Today it will be about gusts and wind-shear, where the wind changes speed/direction quickly. That can be challenging and require diversions.
For crosswinds, most aircraft are limited to around 40 knots (46mph), including gusts. It will be the wind-shear most likely that will be the issue today.”
Go-arounds and diversions
If the weather exceeds wind speed limits during a landing attempt then the pilots must abort the landing and undertake was is called a ‘go-around’ – in other words, they must try again.
There has been no shortage of go-arounds this morning, as you can see on FlightRadar24:
If an aircraft fails to land three times in a row then it is diverted to an alternative airport. Fortunately, this is rare, although three British Airways flights have had to divert this morning including BA296 from Chicago which is going to Geneva:
Two other flights have been diverted to Stansted and Edinburgh.
Wind doesn’t just affect take-off and landing
It’s not just the actual flights that are affected by high winds. Airports also have maximum wind speeds for activities related to flights, including the use of jetbridges, and the towing and loading of aircraft.
The maximum wind speed for jet bridges at Heathrow Terminal 5 is between 41 and 54 knots – or 47 to 62 miles an hour. If the wind picks up any higher (which they are forecast to do) they can become unstable and potentially cause injury or damage.
High winds also prevent flights from being catered. Catering vehicles are pretty unstable at the best of times:
…. so it’s no wonder they can’t operate when it gets windy.
Storm Eunice is causing high levels of disruption at Heathrow and other airports in the South East, but fortunately airport operations are strictly regulated to ensure the safety of all passengers and crew.
That said, I hope airlines have stocked up on sick bags as I doubt these flights are going to be particularly enjoyable as they come into land today ….