DHC8 FLT CREW HAS #2 HYD FAILURE; DECLARES EMER; DIVERTS AND LANDS.

Narrative

WHILE ENRTE; WE JUST COMPLETED VISUAL APCH BRIEFING AND THE IN-RANGE CHKLIST WAS CALLED FOR. AFTER FLOW WAS COMPLETED BY FO; HE BEGAN READING CHKLIST. NOTED MASTER CAUTION FOR RUDDER FULL PRESSURE; #2 RUDDER HYD; AND ROLL SPOILER OUTBOARD HYD CAUTION LIGHTS ILLUMINATED. DISCOVERED #2 HYD QUANTITY SHOWING ZERO. REQUESTED TO ENTER HOLDING AT VOR AND PERFORMED CFM CHKLISTS. CONTACTED DISPATCH THROUGH OPS AND NOTIFIED OF SIT. AGREED TO RETURN TO ZZZ FOR LNDG DUE TO MANUAL GEAR EXTENSION; MOUNTAINOUS TERRAIN; AND DISPLACED RWY ENVIRONMENT. COORD THROUGH OPS; MAINT STAFF; AND DISPATCH. EMER DECLARED AND VECTORED FOR VISUAL APCH TO RWY WITH CFR STANDING BY. ALL CHKLISTS COMPLETE AND GEAR LOCKED DOWN BY ALTERNATE GEAR EXTENSION PROC. UNEVENTFUL LNDG TO FULL STOP ON RWY. ALL GEAR PINNED BY FLT CREW. MAINT STAFF ARRIVED SHORTLY THEREAFTER AND TOWED ACFT TO GATE WITH ALL PAX ON BOARD. PAX DEPLANED AND IN CARE OF GATE AGENTS AND SUPVRS. ACFT TURNED OVER TO MAINT STAFF AFTER WRITE-UPS IN AML. ACFT SWAP AND CONTINUED FLT.