A World War II B-17 bomber with 13 people on board has been involved in a dramatic tragedy at Bradley International Airport in Hartford, Connecticut. The US National Transportation Safety Board has launched an investigation into the accident in which multiple fatalities have been reported. The plane belonged to the non-profit Collings Foundation which restores vintage aircraft and was offering flights that day. Watch:  Ramp worker stops runaway truck from hitting plane The foundation praised first responders and said its thoughts and prayers were with those on the flight. There were 10 passengers and three crew members on the plane when it hit the ground at the end of the runway. [embed]https://www.youtube.com/watch?v=-i81CPmaO7Q[/embed] The Hartford Courant newspaper reported seven dead and seven injured but authorities were being cautious about confirming the figure. "There were fatalities," State Police Commissioner James Rovella told reporters at a news conference, noting that victims were difficult to identify and police did not want to make a mistake. CNN said 14 people were injured including everyone on the plane and at least one person on the ground. Witness Antonio Arreguin told NBC news the plane erupted into “a big ball of orange fire’ and he could feel the heat 250 yards away. “The ball of fire was very big,’’ he said. A recording of an air traffic control conversation indicated the plane had suffered an engine problem. The pilot requested a return to the field shortly after take-off. “What is the reason for coming back?’ the air traffic controller asked. Another pilot said there was a problem with the no. 4 engine. “We’d like to return and blow it out,’’ he added. The pilot said he needed to land immediately and the tower diverted other traffic to allow the B-17 to land but it plunged into the ground at the end of the runway. Videos showed black smoke billowing from the site. The heavily armed B-17, also known as the flying fortress, played a major role in World War II in bombing runs over Nazi Germany. [embed]https://www.youtube.com/watch?v=lDeDogRu3t4[/embed]