Lufthansa flight LH471, a Boeing 747-430 aircraft, was being de-iced on pad number five at the Central De-icing Facility in Toronto LBPIA, (CYYZ). The flight crew was cleared by ‘Iceman’ to taxi out of the de-icing bay via taxiway Tango and hold short of Mike. As the captain applied thrust to manoeuver the aircraft forward, the right wing of the B747 struck de-icing truck number thirteen tipping it over and injuring the driver, who was the sole occupant of the vehicle. The driver was taken to hospital with serious but non-life threatening injuries. Findings as to causes and contributing factors 1. By passing the de-icing strip, the zone de-icing controller (ZDC) indicated to Iceman that the de-icing procedure was complete. In fact, beta truck 13 was still in position ahead of the aircraft’s right wing. 2. On receipt of the de-icing strip, Iceman concluded that the de-icing equipment was clear and issued movement instructions to the flight crew of the aircraft while beta truck 13 was still in position ahead of the aircraft’s right wing. 3. One ZDC was monitoring four active de-icing pads instead of the usual three pads. This increased activity resulted in task saturation and frequency congestion for the ZDC. 4. Because of the increased activity and the radio congestion, the driver/operator of beta truck 13 was unable to effectively establish radio communication with the ZDC to advise that he was still in position in front of the aircraft.