What was found
DURING DEPARTURE, AFTER MAINTENANCE (ENGINE AND THRUST REVERSER) THE NOSE LANDING GEAR DID NOT RETRACT. THE AC RETURNED TO DEPARTURE FOR REPAIR. PROBABLE CAUSE: THE AC WAS JACKED, THE LANDING GEAR WAS FUNCTIONALLY TESTED IAW MM. THE DISCREPANCY COULD NOT BE DUPLICATED. SUSPECTED AN AIR LOCK IN THE NOSE LANDING GEAR RETRACTION SYSTEM. A CHECK FLIGHT WAS PERFORMED WITHOUT FURTHER INCIDENT. (EA09200504998) (K)