Go to Updaam in the Afternoon.
An adrenaline-seeker in Updaam wants to launch himself out of a cannon in the afternoon.
The guy in the cannon has the Cat Fall trinket, thinking he will not be harmed by the fall from the cannon.
By stopping the two NPCs from firing the cannon, and changing the full battery with the half empty battery, you can make him land in Karl's Bay on top of Hanger 1.
Once fired, you can go to Karl's Bay in the evening and find the Cat Fall Trinket on top of Hanger 1.