At start up one of the propellers hit a ground power unit. The no. 2 prop disintegrated with debris puncturing the fuselage. A small fire is said to have erupted. CONCLUSION The cause of the accident during the engine start-up process was the displacement of the aircraft forward and toward the left due to a higher power setting in the engines of the right wing, which caused the No. 3 engine to strike the ground power unit that was positioned in front of the right wing. It was a series of events that contributed to the incident: a) The removal of chocks by ground personnel without having taken them as a precaution and safety measure first, which led to the decision to move the ground power unit that was in front of the right wing of the aircraft. b) Not using ground-to-cabin communication headsets between the cabin crew and the ground technical staff. c) Failing to provide a training course to the ground staff by PHOENIX to GIRAG on the operational procedures on the ground for their aircraft. d) Not taking immediate precautions by the crew concerning the limits that the aircraft had when it lost hydraulic pressure. e) Not ensuring that the parking brakes were set and engaged. f) Not operating the air emergency brake lever by the crew members (Captain or Co-pilot) when they noticed that the aircraft started moving forward for no apparent reason, despite having two levers, one in front of each crew member.