An uplock for selectively retaining a capture pin of a movable element including a hook, a locking member, and a detector. The hook is movable between a release position and a retaining position. The locking member is movable between a locked position that immobilizes the hook and an unlocked position in which the hook is free. The detector detects whether the hook is in the retaining position and the capture pin is present in the hook. The detector includes a sensor associated with a single target which is movable between two positions The sensor emits a signal which is modified when the target passes from one of the positions to the other. The target is independently in kinematic interaction with the hook and the capture pin.