Medium Transport; Low Wing; 2 Turbojet Eng
Situational Awareness
Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Human Factors; Weather
I was the final marshaller on [gate] for arrival flight. I stopped him on the correct line and he set his brakes. I then watched the nose gear tires chocked and gave the tires chocked signal to the pilot. The pilot returned the tires chocked signal. Next thing I see is that the aircraft is rolling back and because of the icy and sandy conditions on the ramp that the chocks are not holding. [Colleague] was able to chock one of the mains on a dry spot after the aircraft had rolled back 3 feet. I was never given the brakes released signal. We towed the aircraft back to the correct parking line.
Aircraft marshaller reported an aircraft began to slide after being chocked at the gate in icy conditions.