The RM-855 radio management unit (RMU) is a fully compatible replacement of the RM-850 with enhanced reliability and capability based on a liquid crystal display unit for additional functionality.

The RM-855 RMU is the primary interface used to control the Primus II radio system in the Primus 1000 and Primus 2000 flight decks.

Key Benefits:

• High frequency tuning, NAV Radio back up tuning, 3rd Com tuning
• Switch COM radios from voice to data mode (when equipped)
• option to show a navigation radio magnetic indicator and engine backup display on the RMU
• Upgrades are easier – software only
• Required for ADS-B Out mandate

The RM-855 Radio Management Unit (RMU) is mounted in the cockpit panel and is the primary interface used to control the radio system functions. The RMU software will need to be upgraded to either the -97X or -98X versions in order to provide the control, testing, and additional failure indications of the ADS-B Out functionality (ADS-B FAIL and ADS-B DGR). The RMU software upgrade will allow for additional communication to the RCZ cluster module on the radio system bus and display of the additional RCZ configuration straps in the maintenance pages.

Required for the 2020 ADS-B Out Mandate on the following aircraft:

• Bombardier Learjet 40 / 45 & 70/75
• Embraer Legacy 600 / 650
• Gulfstream PlaneView Cockpits G350 / 450 / 500 / 550
• Textron Cessna Citation VII, X, Model 560 (Ultra, Encore, Excel and XLS)
• Textron Hawker 800/800xp