B767-200
Flight Crew Air Transport Pilot (ATP); Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument
Communication Breakdown; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Flight Crew Regained Aircraft Control
Aircraft; Procedure
When preparing to pressurize hydraulics; I heard the sound of the ground crew frantically calling us on the intercom coming faintly from the headset. I donned the headset and heard ground crew telling 'the plane is moving! Set your parking brake!' I hastily jumped on the brakes and noticed that they were already set. The captain pressurized the hydraulics which allowed the brakes to engage and stopped the aircraft. We asked why the ground crew had removed the chocks without our permission and they said they do it all the time. It is important to note the brake pressure was indicating above the orange band before hydraulics were pressurized. The flight crew also could not tell the aircraft was moving.Do not allow ground crews to pull chocks until hydraulics have been pressurized and it had been confirmed the parking brake has been set. Residual hydraulic pressure leaks and can cause such a situation; especially when done without flight crew's knowledge.
B767-200 Captain reported ground crew pulled chocks before hydraulics were pressurized and parking brakes were set; causing aircraft to roll.