What was found
CVG - FLT 421 - AFTER TAKEOFF WHEN LANDING GEAR WAS RETRACTED, NLG WOULD NOT RETRACT. LUBRICATED NOSE GEAR, SERVICED STRUT WITH HYDRUALIC FLUID AND NITROGEN. OPERATED LANDING GEAR SEVERAL TIMES AND OPERATION AND INDICATION CHECKED NORMAL. CHECK C - 8-11-96 - STL.