If braking action is reported as nil, what should you advise pilots?

When braking action is reported as nil, it indicates that the runway surface provides no effective braking capability, which poses significant risks during landing. In such conditions, pilots may struggle to control the aircraft after touchdown, leading to potential overruns or loss of control on the runway. Advising pilots to land at another airport becomes crucial as it prioritizes safety by preventing landings in dangerously poor conditions.

When the braking action is nil, alternative options like attempting to land cautiously or landing at their own risk are less advisable because they fail to adequately address the severe implications of inadequate braking performance. The safest strategy is to divert to an airport where runway conditions and braking action are acceptable, ensuring a secure landing environment for the aircraft.