On this day in 2002, an Iranian passenger jet crashes into the side of a mountain, killing all 117 people on board.

Iran Air Tours, a subsidiary of Iran Air, scheduled the Russian-built Tupolev 154 jet to leave Tehran, Iran’s capital city, at 6:30 a.m. It was to be a short flight to Khorramabad, about 200 miles to the southwest, and there was nothing remarkable about the flight until the plane began approaching Khorramabad. Suddenly, the plane dropped off the air-traffic controllers’ radar screens. Witnesses from the village of Sarab-Doreh saw a huge explosion as the plane crashed straight into the snow-covered White Mountain.

The crash site was so difficult to access that only experienced mountain climbers could be enlisted to help with the rescue. By the time they reached the scattered pieces of the plane, they found only the remains of the 117 people on board. Among the dead were four Iranian government officials and four Spanish businessmen.

Although many Iranians are said to have blamed the use of a Russian-made jet for the disaster, the Tupolev-154 jet is, in fact, the mainstay of the Russian air fleet. Approximately 1,000 of the jets have been produced in its lifetime and only 28 have been lost to crashes. This compares favorably with the record of Boeing (the manufacturer used by Iran before the 1979 revolution), which had lost 68 of the 1,500 727s produced before 2002. Furthermore, most of the Tupolev-154 crashes were not due to technical failure. In this disaster, the cause of the crash has never been identified, although there is speculation that heavy fog may have played a role.