Yorkshire air ambulance and its pilot came under attack by a gang of youths throwing stones after being called to help a critically ill patient. The group, who were aged between 12 and 14, started throwing stones at the helicopter after it landed on Woodhouse Moor in Leeds.
Air ambulance paramedic Sammy Wills said the attack could have had a "catastrophic" impact on crew safety.
She said: "We didn't want to take off in case they threw more stones."
Call for help
The attack began after the air ambulance landed to transfer its critically ill patient into a waiting road ambulance, to be transferred to Leeds General Infirmary.
Air ambulance pilot Richard Boswell was left alone with the helicopter while crew paramedics Miss Wills and Tony Wilkes accompanied their patient to hospital.
Miss Wills said: "He became aware of stones being thrown at the aircraft.
"He chased after them and phoned us up to say he was under attack, so we returned and as soon as possible, requested the police and returned to base."
A door of the helicopter was left chipped by a large stone.
Miss Wills added: "To look at it, it seems quite minor, but given the places it could have hit, the implications to the aircraft could have been catastrophic."