A320
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 141; Flight Crew Total 2369; Flight Crew Type 2369
Communication Breakdown; Time Pressure
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Loss Of Aircraft Control
Flight Crew Regained Aircraft Control; Flight Crew Took Evasive Action
Aircraft; Procedure; Human Factors
I coordinated with the Ramp Agent for an early push off the gate; per his request; to ensure their understaffed ramp team could be ready for a subsequent arrival. During pushback; and after clearance to start engines by the Tug Operator; I advised the driver via interphone that we would be holding position on the ramp due to a controlled wheels up time. I queried to ensure there was room for the inbound aircraft to get to their gate. Shortly thereafter I felt the aircraft lurch and I instinctively applied brakes and queried the tug driver if they had a problem with the tug. The driver said no and that they were already disconnected from the aircraft. At no time after the 'Cleared to start engines' call did the push crew advise in accordance with SOP to 'Set brakes.'; nor give the standard tow bar phraseology 'Aircraft disconnected; by-pass pin removed.' After ensuring no one was in harm's way; no injury or damage occurred and clearing up the confusion with the tug driver regarding the lack of required phraseology; the 'Disconnect headset' command was given. As the tug driver backed away; one push crew member showed the tow bar disconnect pin and flag; and then the second team member gave the aircraft clear signal; but then turned and walked away towards their next arrival gate without waiting or noting the acknowledging light flash. The non-standard interphone and push procedures; possibly exacerbated by understaffing of this sub-contracted team; led to an inadvertent aircraft movement.
A320 Captain reported non standard procedures and communication caused the aircraft to roll away after towbar disconnect at push back completion.