Safety Nets Guide

A guide for ensuring effectiveness

Safety nets form an integral part of the ATM system, so much so that they can sometimes be taken for granted. However, their environment evolves so quickly that sustained efforts and constant commitment are needed to optimise and improve them.

The latest edition of our Safety Nets Guidelines gives useful information on using safety nets for maximum benefit.

An introduction to safety nets

Safety nets help prevent imminent or hazardous situations from developing into major incidents or even accidents. The guide’s introductory section gives an overview of the different types of safety nets available, how they interact, and what benefits they provide. It also highlights the dangers of taking safety nets for granted and explains why they should be continuously improved. Details are given on EUROCONTROL’s latest guidelines and on where to find more information.

Action areas for effectively implementing safety nets

Safety nets should not be seen as technical systems working in isolation. Without an appropriate framework to support them, they cannot operate effectively. This section details the action areas needed to set up that framework; it covers the elements that need to be in place:

  • a comprehensive policy
  • organisational clarity
  • training: safety nets evolve rapidly and staff have to be comfortable using them, so they need to be familiar with them and able to detect abnormal behaviour
  • operational and technical procedures
  • system capabilities: technical functionalities and parameter values, which have to be set correctly so as to maximise alerting performance.

All these elements contribute to the successful implementation of safety nets.

The safety net life cycle

Safety nets are only effective if defined properly, implemented correctly, optimised completely and operated effectively.

These steps form the safety net life cycle. This section gives information on how to create one, providing pointers for helpful resources along the way.

Safety net guidelines

For decades, EUROCONTROL has been producing guidelines to help air navigation service providers (ANSPs) best implement safety nets. The latest edition of the Safety Nets Guidelines is known as ‘Level 3’ documentation; it was released in January 2017. It covers these safety nets:

  • Short Term Conflict Alert (STCA)
  • Area Proximity Warning (APW)
  • Minimum Safe Altitude Warning (MSAW)
  • Approach Path Monitor (APM).


Safety Nets Guide