BBC Verify tracked the plane, and found that it began losing altitude off the south-west coast of Ireland. It then headed back east, having dropped to an altitude of 10,000 feet, accoring to FlightRadar24.
At this time, the plane started broadcasting a “7700 squawk code” on its transponder. These are relayed to signify a general emergency onboard, ranging from engine failure to depressurisation to a medical emergency.
In February a government plane carrying Secretary of State Marco Rubio had to turn back due to a crack in the window of the cockpit, as well.
Defence ministers had gathered in Belgium on Wednesday to discuss security in Ukraine.