What was found
AFTER TAKE OFF GEAR HANDLE WOULD NOT RAISE. TRIED HANDLE REL BUTTON PER QRH AND MX DIRECTIVE BUT GEAR HANDLE STILL WOULD NOT MOVE, AIRCRAFT EMERGENCY DECLARED WITH MEMPHIS APPROACH CONTROL. SHGN 02MAR21 01:58 MEM U PERFORMED GVI OF LANGING GEAR, WITH NO OBVIOUS DEFECTS NOTED. 4 EA GEAR PINS ACCOUNTED FOR IN THE FLIGHT DECK. FURTHER T/S REQUIRED. BLED HYD FUSE, FOUND A SIGNIFICANT AMOUNT OF AIR-ENTRAINED FLUID. BLED INTERLOCK CYLINDER. NO FLUID CAME OUT AT FIRST, FOLLOWED BY A SIGNIFICANT AMOUNT OF AIR ENTRAINED FLUID. AFTER BLEEDING, SYSTEM WORKS NORMALLY, INTERLOCK EXTENDS AND RETRACTS AS NORMAL, REF AMM 32-31-05-2 AND AMM 32-37-03-2. JACKED ACFT AND SWUNG GEAR TO VERIFY A POSITIVE FIX. GEAR SWINGS NORMALLY WITH CORRECT INDICATION MULTIPLE CYCLES. ACFT OK FOR SERVICE.