There were conflicting reports about whether there was any smoke aboard the plane.
The airline said it received no reports of smoke, but Romania's Health Ministry said in a statement immediately after the plane landed, “the presence of smoke was confirmed,” and that everyone on board was evacuated.
“Four people are in poor health, possibly being smoke-intoxicated, and are receiving medical assistance on site,” the ministry said, but later added that “they did not require medical care.”
British Airways said in a statement to The Associated Press that “the safety of our customers and colleagues is always our top priority and our crew made the decision to divert as a precaution due to a suspected technical issue.”
“The aircraft landed safely, customers disembarked normally, and we received no reports of smoke on board or hospitalisations,” the airline statment said. "We’re sorry to our customers for the disruption to their journeys and our teams are working to get them on their way again as quickly as possible.”
The airline's flight status page showed Flight BA603 as having been diverted, with the message: “We’re very sorry, this flight scheduled from Istanbul to London, has been diverted to Bucharest.” No further details were provided.