The Airbus A340 belonging to national flag-carrier TAP took off at 10.34am en-route for Brazil but was forced to turn back due to mechanical problems.

It spent some 15 minutes circling over the sea off the coast of Lisbon before landing safely back at the Humberto Delgado airport.

Newspaper Correio da Manhã reported that “the crew flying the Airbus A340 had not been in the air for more than 15 minutes when they decided, in cooperation with the control tower, to discard the planned route and return to land in Lisbon to fix the problems.”

The 177 passengers on board flight TP89 were due to switch planes to continue their journey to their destination.

The causes behind the mechanical failure are being investigated.