Technicians reported lack of currency and management pushing resulting in a loss of control during a towing operations utilizing a Super tug to move a B787. The wheel chocks were removed prior to positive control of the aircraft was established; allowing the aircraft and tug to move several feet.

Narrative

The 787 was parked on a sloped Gate being prepared for aircraft tow. The Super tug Operator docked to the aircraft and neglected to set the parking brake on the super tug. Later; once chocks were removed from the aircraft the super tug Operator began to raise the aircraft. The super tug and the plane rolled a few feet before the Operator realized and set the brakes before continuing to move the aircraft.The super tug used was XXXX which gets very infrequent use. It is specifically designed for wide body aircraft only. The parking brake is slightly different from the other super tug types and does NOT warn the Operator when it is not set. Additionally the Operator is very rarely assigned to move mainline aircraft; much less wide body aircraft. The scheduled work week is typically observing roles in a small tug only with assist tasks 2 days a week and occasionally APU. Meaning there are only two days a week the employee is scheduled in a super tug and they are not evening driving. There have been whole weeks where super tug operation was not assigned at all. Mainline super tug is almost never assigned nor is driving except on overtime or day trades. If the employee got more time with this super tug moving wide body aircraft off of this sloped Gate they would be more aware of the dangers and not fail to set the parking brake on the super tug.More assist roles are being created which leads to less time in super tugs. This creates the proficiency vs currency problem. Yes; we are current in super tug operation in all areas but if we rarely use the super tug then how can we maintain proficiency? Not being able to maintain proficiency with our roles in super tug operation will lead to incidents such as this one or worse.