Approach Path Monitor

An Approach Path Monitor (APM) is a ground based Safety Net intended to warn the controller about increased risk of controlled flight into terrain accidents by generating, in a timely manner, an alert of aircraft proximity to terrain or obstacles during final approach. APM should be used for both precision and non-precision instrument approaches. However, APM is not expected to be used for circling approaches. This Safety Net uses surveillance data, flight plan data (specifically the destination airport) and user-defined limits of the acceptable runway approach paths to achieve its purpose