pf2e.fyi
From Pathfinder Adventure Path: Gatewalkers, which isn't enabled.

Falling Bridge

HAZARD 3
Stealth +13 (trained)
Description The frayed ropes on both sides of this bridge snap when enough weight is put on the bridge's center.

Disable DC 20 Survival (trained) to reinforce and secure the ropes on one side of the bridge

AC 10; Fort +1, Ref +1
HP 6 (BT 3); Immunities critical hits, precision

Collapse
Trigger A Medium or larger creature steps onto the middle of the bridge (any of the squares marked "T" on the map)

Effect The ropes on both sides of the bridge snap simultaneously, causing the bridge to collapse. Any creature on the bridge falls to the forest floor 50 feet below and takes 25 bludgeoning. A creature within 10 feet of one end of the bridge can attempt a DC 18 Reflex saving throw to Grab a Ledge along the side of either A8 or A13.

If one side of the bridge has been disabled by resecuring the ropes, a character on any section of the bridge can attempt a DC 18 Reflex save to hang onto the bridge as one side of it falls. The dangling bridge thereafter functions as a ladder connecting either area A8 or A13 (whichever was secured) to the forest floor.

Pathfinder Adventure Path: GatewalkersORC