MOSCOW, September 6 (Itar-Tass) — Investigators are seizing pre-flight documentation of the supersonic fighter-interceptor MiG-31 that crashed in the Perm Territory on Tuesday. “The seizure of documents concerning the organisation of the flight is underway in the military unit,” law enforcement agencies said.

They noted that the aircraft that was on a training flight was controlled by a lieutenant colonel – the pilot, and a major was the flight navigator.

The investigators still have no information suggesting that the plane could catch fire or explode in the air. “All the circumstances of the air crash are being specified,” a law enforcement official said.

A parachute presumably belonging to one of the pilots was found on the ground.

The press service of the Main Military Investigation Department (GVSU) of the Russian Investigative Committee (SK) told Itar-Tass earlier that a criminal case has been opened over the crash under Article 351 of the RF Criminal Code – “violation of the rules of flights and preparation for them.” Investigators have been examining the crash site. Proceedings to establish all the circumstances of the incident are being conducted.

“The two-seater long-range supersonic fighter-interceptor MiG-31 took off from the Bolshoye Savino airfield outside Perm at about 09:00, local time for a training flight,” the department said. “Several minutes into the flight, the plane disappeared from radar screens. The crash occurred near the Bolgary village of the Perm Territory. Both pilots were killed. There was no destruction on the ground there, the local residents were not hurt.”

The GVSU reported that an investigative team was immediately dispatched to the air crash scene. Forensic officers of the SK Military Investigation Department for the Central Military District went to the incident cite to render practical and methodical assistance to them. The investigation is underway.

According to the RF Defence Ministry, “there were no weapons on board the crashed aircraft.”

The Defence Ministry has formed a commission to investigate the causes of the catastrophe. Flights of this type of fighters have been suspended.

An officer serving on the Sokol military airfield outside Perm told Itar-Tass that the crashed MiG underwent repairs this year.

Series production of the MiG-31 began in 1979 and about 400 were produced by 2000. Some upgrade programs have found their way in the MiG-31 fleet, like the MiG-31BM multirole version with upgraded avionics, new multimode radar, hands-on-throttle-and-stick (HOTAS) controls, liquid crystal (LCD) colour multi-function displays (MFDs), ability to carry the AA-12 ‘Adder’ missile and various Russian air-to-ground missiles (AGMs) such as the AS-17 ‘Krypton’ anti-radiation missile (ARM), a new and more powerful computer, and digital data links. A project to upgrade the Russian MiG-31 fleet to the MiG-31BM standard is nearing completion.

A new version of the MiG-31 with upgraded avionics, the MiG-31B, was introduced in 1990. Its development was the result of the Soviet discovery that Phazotron radar division engineer Adolf Tolkachev had sold information on advanced radars to the West. Tolkachev was executed, and a new version of the compromised radar was hastily developed. Many earlier MiG-31s were upgraded to the new standard, designated MiG-31BS.

Development of a more comprehensive advanced version, the MiG-31M, began in 1983 and first flew in 1986, but the dissolution of the Soviet Union prevented it from entering full production. Since 1991 and especially since 2000, most of the existing aircraft have been upgraded to the MiG-31M standard, also adding some additional features like Global Positioning System (GPS) and GLONASS receivers, and three colour CRT MFDs in the rear cockpit. In the Air Force, aircraft designations are often repeated through the years.

MiG-31M is the heaviest operational interceptor in the world, with a maximum takeoff weight on 56 tonnes. It was even heavier than the commercial Tu-134 airliner at a maximum takeoff weight of 48 tonnes. Several other variants have been developed, including a dedicated anti-satellite missile carrier, the MiG-31D; a similar satellite-launching aircraft, MiG-31A; a proposed multirole version, MiG-31F; and a downgraded export version, MiG-31E; but most have not been built in any quantity, if at all.