The flight, which left Amsterdam at 7.14am, is due to land in Faro at 9.05am. The 7700 code indicates a “general emergency”. It typically means an engineering issue with the aircraft.
It is not yet known why the 7700 signal was transmitted.
Just yesterday, a Jet2 flight from Palma de Mallorca to Edinburgh issued the same signal.
And earlier this month, another flight from the same airline was forced to make an urgent landing after declaring an emergency situation on one of its flights from Alicante to Edinburgh.
A Jet2 spokesman said that a customer onboard required “medical assistance.”