What was found
MIA - FLT 2157 - AFTER TAKEOFF MIA WHEN LANDING GEAR RETRACTED, NOSE LANDING GEAR DID NOT RETRACT. RECYCLED LANDING GEAR WITH SAME RESULTS. EXTENDED LANDING GEAR AND ALL INDICATIONS NORMAL. AIRCRAFT RETURNED TO MIA LANDED WITHOUT INCIDENT. ACCOMPLISHED LANDING GEAR RETRACTION AND FREE FALL CHECKS WITH NO DEFECTS FOUND. CYCLED LANDING GEAR MULTIPLE CYCLES AND OPERATION AND ALL LIGHTS INDICATE NORMAL. UNABLE TO DUPLICATE PROBLEM AND AIRCRAFT RETURNED TO SERVICE. (M)