TERRAIN SERIES: 5G TOLERANT RADAR ALTIMETERS
Cutting-Edge Radar Altitude Technology for all aviation platforms
Precision Altitude Awareness Everywhere
FreeFlight Systems’ TERRAIN SERIES radar altimeters deliver precise, high-integrity altitude data across all aircraft types—from legacy fleets to next-generation platforms—ensuring confident decision-making in every flight phase.
Engineered for Resilience, Designed for Integration
Built to withstand 5G interference and harsh flight environments, TERRAIN SERIES radar altimeters provide accurate Altitude Above Ground Level (AGL) readings in low visibility, extreme weather, and RF-dense areas. With analog and digital interface options, retrofit-ready designs, and global certifications, these systems offer seamless integration and dependable performance for fixed-wing, rotorcraft, UAM/AAM, and autonomous aircraft.
Features
- Efficient: 5G C-Band resistance with advanced RF filtering and DSP
- SWaP Optimized: Small, lightweight (≤ 1.3 lb / 0.59 kg), Low power
- Versatile: Analog output for legacy aircraft (RA-5500 and RA-6500)
- High-Fidelity: High update rate (25 Hz minimum) for real-time altitude data
- Retrofit-Ready: Minimal impact to existing antennas, indicators, and cabling
- Flexible: Multi-interface support (RS-485/422, RS-232, ARINC 429, 552A)
- Display-Friendly: Single install capable with glass displays or RAD-45/RAD-40
- MOPS Compliant: Meets AD 2023-10-02 and 2023-11-07 requirements
- Globally Approved: TSO-C87a, DO-160G, and DO-178C Level B certified
Attributes
Operates reliably near cellular towers and in RF-heavy environments.
Analog output and retrofit-ready design simplify upgrades for older aircraft.
Supports multiple protocols for easy integration with diverse avionics suites.
Meets international standards for safety, reliability, and environmental performance. Dual and singal AML STCs available.
Designed for consistent performance in low visibility, extreme weather, and high-demand operations.
RA-4500 MK II
Purpose-built for rotorcraft, the RA-4500 MK II delivers precise AGL readings with proven performance in low-altitude hover and terrain transitions. Certified to DAL B and C, it replaces the legacy RA-4500 with a modernized design that enables straightforward upgrades with minimal installation impact.
Product Numbers:
84560-50: RA-4500 MKII – DAL B
84560-55: RA-4500 MK II – DAL C
RA-5500
Optimized for UAM/AAM, rotary-wing, and business aviation platforms, the RA-5500 combines high-performance radar altimetry with retrofit flexibility. It integrates easily with existing antennas, control heads, and cabling—making it ideal for upgrading legacy aircraft without compromising capability.
Product Numbers (DAL B):
87990-20: RA5500 Sensor Transceiver
87990-21: RA-5500 Sensor with Analog Display Output
RA-6500
Designed for business, regional, airline transport, and heavy rotary-wing platforms, the RA-6500 offers advanced radar altimetry with single or dual-install options. Its multi-interface architecture includes Ethernet and USB OTG, enabling seamless integration with modern avionics and mission systems.
Product Numbers (DAL B):
87990-10: RA5500 Sensor Transceiver
87990-11: RA-5500 Sensor with Analog Display Output
Radar Altimeter Displays
Both Radar altimeter displays provide the essential Above Ground Level (AGL) information and trend data, enhancing altitude awareness and situational awareness during flight.
Bright LED Read-Outs
With a bright LED read-out, each display delivers clear altitude data via a standard serial interface, allowing real-time monitoring.
RAD-45
Fully compliant with European radar altimeter display and crew alerting standards, the RAD-45 ensures top safety and performance for global aviation operations.
Product Number:
88226-00: RAD-45 Display
RAD-40
Product Number:
84939-00-0200: RAD-40 Display
Altitude Safety in a 5G World
Explore how 5G-tolerant radar altimeters are helping aircraft maintain reliable altitude awareness across commercial, rotorcraft, UAM, and military operations—despite growing RF interference risks.
Precision Altitude Awareness for Every Aircraft Type
Fixed-Wing Aircraft
Ensure safe takeoffs and landings with radar altimeters designed to withstand 5G interference. TERRAIN SERIES helps airlines maintain compliance and reduce disruptions, even on aircraft like the Boeing 787 where interference risks are highest.
Rotorcraft
Low-altitude operations demand precision. TERRAIN SERIES delivers reliable AGL data for EMS, SAR, and corporate missions—even over reflective surfaces like water or ice—where 5G signal reflections can cause malfunctions.
Urban Air Mobility (UAM)
In dense urban environments with strong 5G coverage, TERRAIN SERIES ensures precise altitude awareness for air taxis and autonomous aircraft, supporting safe integration into next-gen airspace.
Military Aviation
Mission success depends on dependable altitude data. TERRAIN SERIES supports tactical low-level flight and landings in RF-heavy zones, helping maintain operational readiness in high-threat environments.
TERRAIN SERIES Frequently Asked Questions
Why do I need a 5G-tolerant radar altimeter?
While some countries have stated that 5G networks won’t interfere with radar altimeters, pilots have reported real-world issues—including erratic altitude readings, autopilot disengagements, and false terrain warnings—even in areas without official advisories. TERRAIN SERIES radar altimeters are engineered to resist 5G C-Band interference, ensuring reliable altitude data during low-altitude operations, approaches, and landings—especially in RF-dense environments.
Are TERRAIN SERIES altimeters compliant with current regulations?
Yes. TERRAIN SERIES radar altimeters meet the latest MOPS standards, including AD 2023-10-02 and AD 2023-11-07, and are certified to TSO-C87a, DO-160G, and DO-178C Level B. This ensures compliance with FAA and international aviation authorities.
Can I retrofit TERRAIN SERIES altimeters into my existing aircraft?
Absolutely. TERRAIN SERIES models are designed for retrofit flexibility, with minimal impact to existing antennas, indicators, and cabling. The RA-4500 MK II, RA-5500, and RA-6500 support both analog and digital integration for legacy and modern platforms.
What types of aircraft are supported?
TERRAIN SERIES altimeters are compatible with a wide range of platforms, including rotorcraft, fixed-wing, business jets, commercial airliners, UAM/AAM vehicles, and military aircraft. Each model is optimized for specific operational needs and installation environments.
How do TERRAIN SERIES altimeters improve operational safety?
By delivering precise Altitude Above Ground Level (AGL) readings—even in low visibility or RF-dense environments—TERRAIN SERIES altimeters enhance situational awareness, reduce accident risk, and support safe landings and low-altitude maneuvers.
What makes TERRAIN SERIES different from other radar altimeters?
TERRAIN SERIES radar altimeters are built from the ground up with next-generation RF circuitry and Digital Signal Processing (DSP) to mitigate 5G interference—without requiring external monitoring systems for filter performance. Unlike legacy systems, they offer SWaP-optimized designs, retrofit flexibility, and multi-interface support for seamless integration across modern and legacy aircraft platforms.
Precision Altitude Starts Here—Download the Brochure.
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