Monitoring Service

Objective and Significance

According to the ICAO requirement, it is necessary for operators operating inRVSM airspace to participate in the RVSM HeightKeeping Performance (HKP) monitoring program for safety reasons.


Monitoring Requirement

According to ICAO, RMA must set up corresponding mechanism to conduct long-term RVSM Height Keeping Performance (HKP) monitoring program.

To provide adequate data whilst not imposing excessively onerous requirements on operators, ICAO proposed a Height Keeping Performance (HKP) monitoring program (MMR) which should be carried out by RMAs. Please check the detail information of Minimum Monitoring Requirement.

Civil Aviation Administration (CAAC) has carried out the HKP monitoring since RVSM was implemented in China. CAAC also raised clear request to aircrafts which have got RVSM approval for the original monitoring according to “Operational Requirement for RVSM” (AC-91-07).

In relation to Height Keeping Performance Monitoring (HKPM) requirements, monitoring data from any regional monitoring programme established in accordance with Annex 11,, maybe used to satisfy the requirement.

Height Keeping Performance which is representedby Total Vertical Error (TVE), Altimetry SystemError (ASE) and Assigned Attitude Deviation(AAD), is the observed performance of an aircraftwith respect to adherence to cleared flight level.As ASE have a fair chance of threating the safetyof RVSM airspace operation, it is vital to demonstratewhether ASE is compliant.

According to ‘Manual on Implementationof a 300m (1000ft) Vertical Separation MinimumBetween FL 290 and FL 410 Inclusive’ (Doc9574)and general international standards, the compliant aircraft must meet these criteria:

|TVE| < 90m(300ft)

|ASE| < 75m(245ft)

|AAD| < 90m(300ft)

According to a general international criteria, China RMArecognizes those aircraft whose measured ASE exceed 180ft is called aberrant. The operators need to immediate actions for those aircraft whose measured height-keeping deviations are non-compliant.

Monitoring Systems

There are three monitoring methods all over the word:

► On-board monitoring with GPS Monitoring Unit (GMU) and Enhanced GPS Monitoring Unit (EGMU).

► Wide Area Multilateration Monitoring System

       • Height Monitoring Unit (HMU):

       (a).The European Regional Monitoring Agency(EURRMA), operated by Eurocontrol:


       (b).TheNorth Atlantic Central Monitoring Agency (NAT CMA): contact UK NATS at

       (c).TheJapan Safety Monitoring Agency (JASMA), operated by JCAB:

        • Aircraft Geometric Height Measurement Element (AGHME):

       (a).The North American Approvals Registry and Monitoring Organization (NAARMO), operated by United States Federal Aviation Administration's William J. Hughes Technical Center (FAA-WJHTC):

     ► ADS-B Height Monitoring System

          • TheChina RMA:

          • The Australian Airspace Monitoring Agency (AAMA), operated by Airservices Australia:

          • The Monitoring Agency for Asia Region (MAAR), operated by AeronauticalRadio of Thailand,Ltd. (AEROTHAI)

        Currently, the monitoring data of ground-based monitoring systems are shared between RMAs, not directly to the operators. So the operators under the China RMA’s responsibilityare requested to contact the China RMA firstly when there is a need of the monitoring data of ground-based monitoring systems outside China. The operators could use the information above to know the locations and service status of the ground-based monitoring systems.