An Air Canada flight from Toronto skidded off the runway as it landed at the Halifax Stanfield International Airport on Sunday, sending 23 people to hospital with injuries that are not considered life-threatening.Flight AC624 "took a very hard landing and skidded off the runway", Halifax Stanfield International Airport spokesman Peter Spurway said."Right now, we have some minor injuries. Nothing that is deemed to be life-threatening," CBC News reported Spurway as saying.There were 133 passengers and five crew members on board. Officials originally said only 16 people were injured in the incident. Spurway said the incident was not a crash because it is believed the plane was under control as it came in. He said there was no indication what caused the hard landing and he did not know the condition of the plane.Electricity was out at the airport at the time of the incident, and remained off for at least an hour. Passenger Randy Hall said the plane was circling the airport for at least 30 minutes waiting for a good time to land. As the plane was coming down, there was "a big flash", he said.Passenger Denis Lavoie said he saw sparks coming from the plane and that it bounced twice upon landing. The passengers left through the emergency exits after the plane came to a stop.