According to the THY press office, the plane took off from Istanbul's Sabiha Gokcen Airport at 10.30 a.m. local time (0830 GMT).
While on air, the pilot contacted the airport traffic control tower at Nürnberg Airport and landed out of abundance of caution, the press office said.
Security measures have been taken around the plane and the passengers led into the terminal, as the cabin and the mobile phone are being checked, Anadolu News Agency reported.