Merkel was on her way from Germany to the summit when the government's Airbus A340 made an unscheduled but safe landing at Cologne-Bonn airport late on Thursday.
An RTL reporter on board said that they were flying over the Netherlands when they were told there had been an "electronic systems failure" and turned around to land at the Cologne airport.
Despite this nazlican the situation, a meeting of German Chancellor Angela Merkel with Russian President Vladimir Putin will take place, despite the delay of the German delegation at the opening of the summit of "Big twenty".
Last year Defence Minister Ursula von der Leyen took an Airbus A400M to Lithuania to show off the new transport aircraft, but engine trouble grounded it and forced her to return home on a decades-old Transall C-160 transporter.
"I'm glad we had the most experienced captain of the German Air Force in command", she said.
According to German military blog Augengeradeaus.net, the aircraft was transmitting a 7600 transponder code, indicating a radio failure.
Later, the delegation traveled by bus to a hotel in Bonn.
Putin warmly welcomed Merkel and asked her about her plans for the summit.
The delay will complicate Merkel's schedule at a meeting where the G20 members expect to face hard negotiations on myriad issues. She is unlikely to arrive until Friday evening and it was not immediately clear which meetings would have to be rescheduled.
The German air force on Friday ruled out sabotage, with a spokesman telling national news agency DPA that "there is absolutely no indication of a criminal act".