Wiktionary
unchock
vb. (context transitive English) To remove the chocks from (a parked aircraft, trailer, etc.).
Usage examples of "unchock".
The Brigaderos crew scrambled to unchock the wheels of the battery, and it crept laboriously backward as the straining engine tugged it safely within the gates of the earth-bermed camp.
He'd been helping a crew unchock the A-6 Intruders parked forward of the island.