After the implementation of the airspace change which has introduced PBN, the system needs to be monitored to ensure that safety of the system is maintained and determine whether strategic objectives are achieved. If after implementation, unforeseen events do occur, the project team should put mitigation measures in place as soon as possible. In exceptional circumstances, this could require the withdrawal of RNAV or RNP operations while specific problems are addressed.
It is evident that during the development and implementation of an airspace change reviews need to take place: once before and once after implementation.
The Post implementation review is concerned with monitoring and checking the effects of the implementation in order to ensure that unforeseen consequences do not arise. If they do, the airspace design team should put in mitigation measures (or redundancy procedures) in place as soon as possible.
As can be appreciated, the proper planning of an airspace change and robust implementation planning should ensure that drastic or radical action during the implementation n ‘switch on’ is not necessary during the post implementation review phase. Nevertheless, the team should be ready for all possible eventualities
The post implementation review phase will enable the design team to critically assess the implementation scenario in the same way as it had done with the Reference Scenario in the planning phase. A Quick Reference list provided here may assist the design team; however, the development of a local Post Implementation Review checklist is highly encouraged.
The output of this review will then, eventually be fed back into the System Safety Assessment (SSA) and it will also form the basis of the review when the next airspace change needs to be made.
A System Safety Assessment should be conducted after implementation and evidence collected to ensure that the safety of the system is assured – see ICAO Safety Management Manual, Doc 9859.