What was found
YYC - FLIGHT 2331 - AIRCREW RETURNED TO FIELD WHEN AFTER TAKEOFF THE LANDING GEAR FAILED TO RETRACT. THE CHECKLIST WAS RUN BUT THE GEAR STILL FAILED TO RETRACT. MAINTENANCE INSPECTED THE AIRCRAFT AND INTERROGATED THE PSEU. THE PSEU REPORTED -NWCENT UNREASONABLY FAR-. THE NOSE GEAR PROXIMITY SENSOR WAS FOUND TO BE IN RIG. NO OTHER DISCREPANCIES WERE NOTED. MAINTENANCE CLEANED AND LUBED THE NOSE GEAR SWITCHES AND SENSORS, PERFORMED OPERATIONAL CHECKS, AND RETURNED THE AIRCRAFT BACK TO SERVICE. NO PARTS WERE REPLACED.