What was found
NLG LANDING GEAR RETRACTION: INFLIGHT, AFTER GEAR RETRACTION RED UNLOCK LIGHT REMAINS ILLUMINATED. ALL 3 GREEN DOWN LIGHTS WERE EXTINGUISHED.//CORRECTIVE ACTION//JACKED UP AIRCRAFT. CHECKED NOSE STRUT EXTENSION AND FOUND TO BE AT THE CORRECT DIMENSION OF 9.1 INCHES. HOOKED UP THE MULE AND COMPLIED WITH SEVERAL GEAR SWINGS NO ISSUES NOTED IAW CE-560XL AMM 32-30-00. ADJUSTED SWITCH AS REQUIRED IAW CE-560XL AMM 32-61-00. SERVICED HYDRAULIC RESERVOIR IAW CE-560XL AMM 12-12-01. RETURNED AIRCRAFT TO ORIGINAL CONDITION