runway visual range "runway visual range" means, in relation to a runway, the distance in the direction of take-off or landing over which the runway lights or surface markings may be seen from the touchdown zone as calculated by either human observation or instruments in the vicinity of the touchdown zone or, where this is not reasonably practicable, in the vicinity of the mid-point of the runway; and the distance, if any, as communicated to the commander of an aircraft by or on behalf of the person in charge of the aerodrome as being the runway visual range, shall be taken to be the runway visual range for the time being; PU(A) 139/1996 - CIVIL AVIATION REGULATIONS 1996 2. Interpretation.