Airservices is Australia's air navigation service provider - we provide air traffic control, aviation rescue and fire fighting and air navigation services.

ADS-B Height-Keeping Monitoring

ADS-B Height-Keeping Monitoring System (AHMS)

The use of ADS-B as a means to estimate ASE and comply with the ICAO Annex 6 Long Term Height-keeping Monitoring Requirements has been endorsed by ICAO following extensive joint research by Australia (AAMA) and the United States (FAA). With the global implementation of long term height monitoring requirements such a system provides a significantly low cost, efficient means to undertake long-term height-keeping monitoring without any operational impact on ADS-B equipped aircraft.

Area of Implementation

Currently, use of the AAMA AHMS is restricted to aircraft observed within the Australian ADS-B network. The AAMA is planning to extend the implementation to include the Indonesian FIRs in the future.

ADS-B Monitoring Description

ADS-B monitoring is undertaken by the AAMA through the monthly processing of large data sets of ADS-B messages captured in the Australian network. The data is processed to enable the calculation of altimetry system errors for each ADS-B message obtained from a specific aircraft or group of aircraft. A final assessed ASE value is then calculated for each observed aircraft.

ADS-B messages used for Height-Keeping Monitoring must include geometric height. Operators wishing to participate in ADS-B Height-Keeping Monitoring must ensure that geometric height is included in transmitted ADS-B messages.

Monitoring Process

The monitoring process used by the AAMA is as follows:

  1. Extract and process ADS-B data from the Australian network each month. ASE calculations will be completed and reviewed to identify any airframes that may be indicating height-keeping errors close to or exceeding acceptable limits.
  2. Notify relevant State authorities of aircraft that demonstrate aberrant height-keeping capability so that those authorities may take corrective action as required by provisions of Annex 6.
  3. Publish to its web site information on the last successful monitoring date of aircraft fully RVSM approved by the State authorities of Australia, Indonesia, Nauru, Papua New Guinea, the Solomon Islands and Timor-Leste.
  4. Provide information to other Regional Monitoring Agencies (RMAs) of the last successful monitoring date of aircraft fully RVSM approved by State authorities other than for those States for which the AAMA is responsible. The relevant RMA will publish the information obtained from the AAMA in this way, on its web site.