Cushioning Charm

From UnknowableWiki

The Cushioning Charm is a spell applied to broomsticks. It creates an invisible cushion on the handle of the broomstick, resulting in more comfortable flight. It was invented by Elliot Smethwyck in 1820 (QA9).

Apparently, the Cushioning Charm can also be cast on people, as is done by Hermione Granger on herself, Harry Potter, Ron Weasley, Griphook and Bogrod in order to avoid a hard collision against the rocky floor near Gringotts' vaults, after the cart they had been riding on flips over. The spell causes the Trio and the goblins to glide towards the ground, as though weightless (DH26).

The charm used by Hermione on this occasion could also be a type of Cushioning Charm, and not necessarily the same one that was invented by Elliot Smethwyck.