A320
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 127; Flight Crew Total 1418; Flight Crew Type 569
Communication Breakdown; Workload; Distraction; Time Pressure
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Loss Of Aircraft Control
Flight Crew Regained Aircraft Control
Human Factors
We pushed back from ZZZ gate XXX at XA:04Z. Clearance is not required. We had a wheels up time of XA:31Z. During the push I coordinated with Ground Control where they wanted us to park the aircraft after the pushback. Ground Control stated we could keep the aircraft on the uncontrolled ramp until the time came to taxi for departure. The Captain was communicating with the pushback ground crew. The aircraft was stopped; I did not hear 'set brakes' or 'parking brake set; pressure normal' by the ground crew or captain when the aircraft moved forward and then suddenly stopped. The Captain asked the ground crew what just happened. The ground crew responded he thought the parking brake was set at the time the aircraft moved forward. The Captain stated the brakes were not set and that he never stated they were set and reminded the ground crew of the correct phraseology. The Captain also asked if everyone was okay on the ground. The ground crew stated everyone was alright on the ground. We finished the disconnect process and continued with the flight.
A320 First Officer reported a communication breakdown with the ground crew; that resulted in the aircraft rolling after the tow bar was disconnected.