RVSM Height-Monitoring Process
To verify that altitude-keeping systems are compliant with RVSM requirements, ARINC uses a Global Positioning System (GPS)-based monitoring system.
For monitoring in North America, ARINC collects global positioning data in flight, using a portable GPS-based Monitoring Unit (GMU) that ARINC developed for the FAA.
The GMU weighs about 25 pounds, is portable, and fits beneath the passenger seat in the cockpit of most commercial aircraft. Installed and activated by a staff specialist on each flight, the GMU is an accepted portable electronic device that uses aircraft power when available (28 Vdc, 110 Vac, or 220 Vac).
The monitoring flight requires approximately 30 minutes of straight and level flight between flight levels 290 and 410. ARINC processes the data by applying differential corrections to the raw GPS data collected during the flight and submits it to the FAA Technical Center. The FAA Technical Center then determines the total vertical error (TVE) which is used to grant or deny airworthiness approval.
In Europe, ARINC works closely with EUROCONTROL to offer height monitoring services. Through licensed agreement, ARINC uses the EUROCONTROL GMU. The unit weighs about 5.4 kilograms and operates off of an internal 14.4 V battery.
The monitoring flight requires 30 minutes of straight and level flying at a flight level between 290 and 410. Data collected by the EUROCONTROL GMU is then sent for processing by the ARINC EMEA Division in the United Kingdom, where the TVE is calculated and the results are returned to EUROCONTROL.
Operators obtain airworthiness approval from the appropriate state authority. State authorities then notify their regional Central Monitoring Agency that the aircraft meets RVSM authority for the appropriate regional RVSM airspace.