By Aleks Phillips – U.S. News Reporter

A plane traveling from Moscow to Khanty-Mansiysk, a city in central Russia, was forced to return to its point of origin due to a mechanical failure while carrying “radioactive cargo,” Russian sources associated with the security services have claimed.

A UTair Boeing 737 left the Russian capital’s Vnukovo International Airport shortly after midnight local time on Monday and was due to arrive at its destination around 10 a.m., but after 40 minutes in the air returned to the Moscow airport having circled south of the city several times, flight radar data shows.

SHOT, a Russian Telegram channel, said the same day that the plane was carrying 104 people and 19 kilograms of an unnamed “radioactive substance.” It attributed the aborted flight to “a landing gear malfunction” and that the “dangerous cargo onboard was not damaged.”

Another Telegram channel thought to be linked to the Russian security services, Baza, also said the flight had been carrying 19 kilograms of “radioactive cargo” and 104 passengers, but claimed the flight was heading towards Moscow when it reported the issue.

In a statement, the Ural Transport Prosecutor’s Office said the flight had “reported a comment on the wing mechanization” which had let to it returning, and that landing “was completed safely.” However, it said there were 66 passengers onboard at the time.

The Prosecutor’s Office also noted that passengers were able to board a different plane which took them to Khanty-Mansiysk shortly after 8 a.m. local time, which flight records confirm.

Newsweek approached UTair via email for comment on Tuesday.

Russian outlet 86.RU reported, citing the airline, that the plane had been carrying cargo destined for an oncology hospital, though Newsweek could not immediately verify this.

Plane malfunctions in Russia have tripled in a year as Western sanctions imposed in response to the invasion of Ukraine have led to a lack of spare parts for machinery across a range of industries, including aviation.

Data compiled by Newsweek shows that so far in 2023 there have been 180 incidents involving commercial planes making emergency landings due to technical issues, while in 2022 there were just 61.

From September to December 8 this year alone, there were 60 incidents where engine fires, malfunctions or other technical issues were cited, forcing the planes to abandon their intended routes.

In 2022, a Yale School of Management study using “unconventional” data sources argued that, at the time, as much as 40 percent of Russia’s gross domestic product was under threat due to Western economic sanctions.

It said that a multitude of companies withdrawing from the country or refusing to trade with it had led to anecdotal reports that Russians—both domestically and in the military—were having to “cannibalize” old appliances for machine and automobile parts.

“Within aerospace, flag-carrier Aeroflot and others have been cannibalizing existing aircraft parts to continue servicing the operations of its remaining fleet, even though operators such as Boeing have cut off all support and service and have issued warnings that cannibalized aircraft are not safe for operation,” it said.

“Some carriers, such as Pobeda, have even intentionally grounded up to 40 percent of their existing fleet to provide parts to service and operate the remaining fleet,” it added.