What was found
(CAN) DURING TAKEOFF, THE FLIGHT CREW REPORTED THE GEAR WOULD NOT RETRACT WHEN SELECTED UP. THE APPLICABLE CHECKLIST WAS CARRIED OUT AND THE GEAR RETRACTED ON THE SECOND ATTEMPT. AFTER AN UNEVENTFUL LANDING, MAINTENANCE CARRIED OUT THE FOLLOWING ACTIONS BEFORE RETURNING THE ACFT TO SERVICE. FOUND MANUAL EXTENSION SYSTEM ACCESS DOOR SWITCH LOOSE. SWITCH SECURED AND ADJUSTED IAW AMM 32-34-00 WHICH INCLUDED MULTIPLE GEAR SWINGS FOR CONFIRMATION.