B767-300 and 300 ER
Maintenance Airframe; Maintenance Powerplant
Distraction; Time Pressure; Confusion; Communication Breakdown
Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Procedure; Aircraft; Human Factors
I was assigned to the 'A' check and working the Flight Deck task cards on Aircraft X. I needed to reconfigure the flight controls to complete two remaining tasks which included the Flap/Slat Electronics Unit (FSEU) Operational Check and the Cat III operational check.  Before turning on hydraulics I obtained clearance. I then noticed that the flap handle was in up position but the flaps were in actuality in the down position.I also noticed that the speed handle in the down position but the spoilers were in actuality in the up position. I decided before turning hydraulics on to reposition the flap handle to coincide with the actual position of the flaps. I also knew that even though engine No. 1 cowling and thrust reverser was still open; the leading edges were already in the up position. I therefore assumed that the leading edges would not move and once I turned on hydraulics that the flaps would retract and the leading edges would remain stationary. Unfortunately; I was wrong. The leading edges began to move instead of remaining stationary.  After consulting with other mechanics; the leading edges sensed that the flaps were down and needed to be down and therefore started to move.I then received verbal communication from the ground to stop my actions but before I could shut down hydraulics the leading edge made contact with the No. 2 engine thrust reverser. I Sincerely apologize and take full responsibility for my action.
Maintenance technician reported leading edge devices extended and contacted the open engine cowling during a routine check.