Aviation experts have begun an investigation after passengers were evacuated from a plane as it was about to take off from Belfast City Airport.
Aircraft was towed away for examination
Fifty four passengers left the the British Aerospace 146 jet by sliding down the emergency chutes during the full scale fire alert.
The incident happened just before 0900 BST on Friday when the pilot noticed smoke in the British Airways aircraft as it prepared for take off.
The flight had been due to go to Manchester.
A British Airways spokesman said: "All the passengers were on board and, as
it was pushing back from the stand, they noticed a slight haze of blue smoke in
"The captain decided as a precautionary measure to have a full evacuation and
emergency slides were deployed and all passengers safely evacuated down the
Four people were injured during the evacuation of the aircraft, according to the ambulance service.
Divisional officer Gordon Latimer said extra fire crews weren't needed
One woman was taken to hospital with a minor back injury after sliding down the evacuation chute.
Another woman received oxygen after suffering an asthma attack, while two other passengers also required medical attention. None of these injuries required hospital treatment.
Passengers on the plane had to wait in the British Airways lounge for a replacement aircraft.
Several airport fire tenders and 10 fire engines from local stations as well as police and ambulance personnel were called as a precautionary measure.
Divisional officer Gordon Latimer, from the fire service, said the incident was treated as a full emergency, but luckily his officers were not needed.
"Because of the potential for disaster we would send what we call a predetermined attendance," he said.
"In this case, for a full emergency, we would send 10 fire engines from around the Greater Belfast area and from north Down in the case of Belfast City airport.
"Thankfully in this case they weren't required."
The aircraft was later towed away for examination.
BA split the passengers involved in the alert onto a number of other flights.