Ethiopian Airlines has suspended the flight crew after both pilots allegedly fell asleep and missed their landing opportunity in Addis Ababa.

The flight eventually successfully landed, but experts said the incident highlighted concerns about pilot exhaustion on the airline, Africa’s largest.

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According to the Aviation Herald, a news website for the aviation sector, the two pilots were flying a Boeing 737 from Sudan’s capital, Khartoum, to Addis Ababa on Monday.

“After overflying [the runway] … the autopilot disconnected, the disconnect wailer woke the crew up, who then maneuvered the aircraft for a safe landing,” the report stated.

According to Ethiopian Airlines, the crew has been “removed from operation pending further investigation. Appropriate corrective action will be taken based on the outcome of the investigation. Safety has always been and will continue to be our first priority.”

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The statement did not specify if the pilots had slept.

According to experts, the event could have been caused by the airline overworking the pilots or by other external reasons.

According to Hassan Shahidi of the Flight Safety Foundation, an independent nonprofit organisation, pilot fatigue “would certainly be investigated in terms of exactly how many hours they were flying and potentially whether fatigue or scheduling may have played a role in this, but it is, at the end of the day, the responsibility of the crew if they are fatigued or if they are tired, to report that they’re tired.”

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Airlines that fly into and out of the United States and the European Union, such as Ethiopian Airlines, are subject to safety regulations imposed by regulatory agencies in those countries. Failure to comply with these guidelines may result in airlines being barred from flying to US and EU destinations.

The European Union Aviation Safety Agency informed news website VOA through email that it was aware of the situation.

According to the agency, it considers information from multiple sources as part of its ongoing surveillance of non-EU air carriers “and takes action as appropriate to ensure operations meet our safety expectations.”

The agency stated that it does not comment on specific instances.