The training version of the F-13 The MiG-21U-400 is the trainer version of the MiG-21F-13. It was also called the "66-400". The Hungarian People's Army introduced 12 of them, which served between 1964 and 1987. NATO reporting name: Mongol-A. It was equipped with functions to help training The U-400 prototype first flew on October 17, 1960. Unlike the F-13, the Pitot tube was placed on the top part of the nose. The lighting of the instruments was changed: instead of UV rays, a red light was used, which is better suited to night flying. It had no weapons installed. From the rear training seat the instructor could simulate problems with the pilot’s instruments. The front cabin could be fitted with curtains for practicing night flying and technical flying. In Hungary The Hungarian People's Army received their first four MiG-21Us on October 25, 1963. Two were stationed in Pápa and two in Taszár. Of the twelve planes received and used one was destroyed, causing two deaths.