U.S. Secretary of State John Kerry was forced to take a commercial flight back to the U.S. from Vienna after his U.S. Air Force jet broke down -- for the fourth time this year, Agence France-Press, or AFP, reported. Kerry was in Vienna for talks on Iran’s nuclear program.

Kerry and 40 of his staff from the State Department, and accompanying journalists, were checking out of their hotel rooms when they heard the news that the Boeing 757 was in need of unspecified repairs. Kerry has so far recorded about 566,000 miles on the jet by travelling to 55 countries since he took office in February 2013.

Kerry has so far spent nearly 250 days on the road, while his predecessor, Hillary Clinton, flew a million miles, travelling to 112 countries, in the four years that she was Secretary of State, AFP reported.

The plane had last broken down in August at Hawaii’s Hickam Air Force Base due to electrical problems, the New York Times had reported at the time.

In March, there was a technical problem with the plane when Kerry was in London. The problem was hastily fixed while his team was anxiously searching for flights back home, AFP reported. In January, a transponder was flown from the U.S. to Switzerland, where Kerry was attending talks with international leaders on the Syrian conflict.