The first incident involved a Tap flight from Helsinki, Finland, to Lisbon, on Saturday 9 May.
According to the report on aviation website Aviation Herald the flight was climbing out of Helsinki “when the crew stopped the climb (…) due to a radio failure. The crew then descended the aircraft back to 5,000 feet to burn off fuel and returned to Helsinki for a safe landing about two hours after departure.”
The aircraft was reportedly repaired and departed again after around an hour on the ground and reached Lisbon with a delay of three hours and fifteen minutes.
On Tuesday this week a second TAP flight was dogged by a technical glitch.
Newspaper Correio da Manhã reported that a Portugália plane heading for Lyon, France from Lisbon was forced to return to Portela airport due to a technical problem.
A source for national flag carrier TAP, which was operating the flight, said the problem with the Fokker 100 aircraft was detected shortly after takeoff.
Flight TP 472 circled for around one hour to burn off fuel before returning to Lisbon. The 91 passengers were transferredto another plane and departed later that afternoon.