From Deutsche Welle:
Angela Merkel's plane experiences technical defect en route to G20 summit
German Chancellor Angela Merkel's plane had to turn around and land in Cologne after only an hour in the air due to a defect. The plane has experienced several issues in the past few months. German Chancellor Angela Merkel's journey to Buenos Aires for this weekend's G20 summit was interrupted on Thursday after the government's "Konrad Adenauer" Airbus experienced technological difficulties in the air.
Issues with the government's A340 jets also caused travel problems for German President Frank-Walter Steinmeier during several of his diplomatic trips this year.
Shortly after departing from Berlin on Thursday evening, the plane circled over the Netherlands and landed at the Cologne/Bonn airport in western Germany — which is also home base for the German government's aircraft.
Merkel, who is also traveling with Finance Minister Olaf Scholz and a pool of journalists, hoped to switch into a replacement plane at the airport, but it is unclear how the travel interruption will affect the chancellor's attendance at the G20 summit — which is due to start tomorrow.
The pilot informed the chancellor and other passengers that a technical defect had caused several electronic systems on the Airbus A340-300 to fail, reported news agency DPA.
https://www.dw.com/en/angela-merkels-plane-experiences-technical-defect-en-route-to-g20-summit/a-46514663
She normally travels on A340 16+01 Konrad Adenauer.