Story highlights Air France Flight 953 narrowly missed Mount Cameroon, investigators say

The Boeing 777 had turned off its planned route to avoid thunderstorms

The pilots responded appropriately when an alarm went off, the airline says

(CNN) An Air France passenger jet had a near miss with an active volcano in Africa earlier this month, according to French aviation authorities who are investigating the incident.

Air France Flight 953, a Boeing 777 with 37 people aboard, was on a short evening journey from Equatorial Guinea to Cameroon on May 2 when it steered off its planned route to avoid thunderstorms.

As the aircraft turned back toward its destination, the city of Douala in Cameroon, it got too close to Mount Cameroon, the highest mountain in the region whose volcano is still active, said the BEA, France's air accident investigation agency.

The "pull up" alarm started sounding and the pilots responded by ascending from 9,000 feet to 13,000 feet, the BEA said. The alarm stopped and the flight went on to land in Douala, it added.

In a list of open investigations, the agency described the close shave as "a serious incident" that involved "controlled flight into or toward terrain."

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