A 7700 squawk alert signifies a general emergency. The flight took off from Sal International Airport, Cape Verde’s main international airport, at 23:19 (UTC) after being delayed from its original departure time of 19:55 (UTC).
The Boeing 787-8 Dreamliner was en route to Bristol Airport and was due to land at 6:36 a.m.
According to Flightradar24, the flight was diverted to Birmingham Airport (BHX).
The flight’s radar map shows the flight landed at West Midlands Airport.
It follows weeks of chaos for travelers at UK airports, with German travel giant TUI seeing hundreds of flights affected.
The tour operator previously apologized for the delays and cancellations, adding that it was doing “everything we can to limit flight delays”.
They also advised travelers against arriving at departure airports too early, as this could worsen wait times.
Thousands of passengers faced further disruption on Wednesday morning after low-cost airline EasyJet cut at least 35 flights on Tuesday.
WizzAir cut a number of scheduled departures, with British Airways cutting 124 flights from Heathrow.
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The government has blamed the aviation sector for accepting more passenger bookings than operators can handle.
Last week, Transport Secretary Grant Shapps said airlines had “severely oversold flights and holidays”, saying the government had done its part to support the sector.
But Mike Clancy of the Prospect union called the government “guilty” of withdrawing pandemic support from the sector too quickly.
He told the BBC: “Unless government and employers can come up with a long-term sustainable plan for the aviation industry that supports jobs and skills, it’s hard to see the situation improving. “