Point Merge is a unique RNAV-based procedure utilized by Air traffic controllers at a limited set of aerodromes to sequence and merge arrival flows from different directions into an approach sequence feeding a single runway.
Contrary to conventional radar patterns, Point Merge procedures consist of several pre-defined, vertically separated sequencing arcs (mostly two) equidistant from a merge point instead of linear radar pattern legs. The sequencing is achieved through instructing aircraft to proceed directly to the merge point from any position in the arc as soon as the desired spacing to the preceding aircraft in sequence has been established. This means that actually no radar vectoring is required at all, as in-trail spacing along the arcs and on the way to the merge point is mainly managed through speed control.
Therefore, every Point Merge procedure is implemented into a STAR or transition to final approach as a closed procedure as the last fix is connected with the merge point. This last fix shouldn’t be reached by aircraft under normal circumstances as this shows the controller that the procedure is overflowing and the demand exceeds the method‘s delay absorption capacity, reflected by the arc lengths. If there should not be the need of a delay for sequencing aircraft may even proceed directly from the entry fix to the merge point.
In most cases Point Merge procedures are located in such that way that they can directly be followed by a precision approach procedure (e. g. ILS), or an RNAV approach. The advantage is that it ultimately leads to more orderly traffic flows with an improved view of arrival sequences and simplifies controller tasks with reductions of communication and workload during peak times.
As Point Merge has to be built into the terminal procedures, only 28 places in the world are capable of utilizing this method. The most popular examples include Kuala Lumpur, Dublin, Paris and Oslo.
To visualize the method, an example of an application in Paris with two Point Merge procedures can be found here.