G-AGRH Zephyr was an Avro Super Trader IV cargo aircraft which crashed on Mount Süphan in eastern Turkey on 23 April 1959.

A special Royal Air Force mountain rescue team of six men from Nicosia, Cyprus reached the crash site at the top of the mountain some days later and demolished the plane wreckage with explosives after retrieving several important documents.

An anonymous source alleged that, some years later, some local villagers who went to the wreck were diagnosed with cancer and died due to high exposure to the radioactive substances.

[citation needed] The official investigation into the accident concluded that the aircraft, which had been flying on instruments, drifted north of its normal track because of strong winds and crashed into the mountain.

In addition to this, sub-normal temperatures would have resulted in a high indicated altimeter reading and calculations on the flight and contacts with beacons were not coordinated and controlled.