Honeywell KRA-405B

The KRA-405B radar altimeter (RADALT) is a lightweight, solid-state device that provides precise altitude measurements during various flight phases. With over 10,000 units sold and four million service hours, it’s one of the most reliable radar altimeters on the market, even in challenging 5G environments. It features a frequency range of 4.2-4.4 GHz, operating up to 2,500 feet, and offers high accuracy. The KRA-405B also meets FAA regulations when paired with an external bandpass filter to mitigate 5G interference.

Lightweight, Reliable Radar Altimeter with Proven Performance

The KRA-405B radar altimeter (RADALT) is a lightweight, solid-state, airborne altimeter that provides accurate altitude measurements above terrain during various portions of flight. With more than 10,000 produced and sold to date and more than four million service hours, the KRA-405B RADALT has proven to be one of the most reliable and industry proven radar altimeters available, even in the modern 5G environment.

Key Benefits:

Frequency: 4.2 GHz to 4.4 GHz
Operating range: 0 to +2500 feet
Accuracy: ± 3 ft or ±3%, < 500ft. ±5%, >500ft.
Analog and digital outputs
Temperature range: -55°C to 70°C (operating), -55°C to 85°C (non-operating)
Size: 3”x3.5”x11”
Weight: 3 pounds
TSO C87/ETSO-2C87 (1997) airborne low-range radio altimeter
DO-160B (environmental conditions and test procedures for airborne equipment)
DO-155(minimum performance specification - airborne low-range altimeters)
DO-178B Level A (software considerations in airborne systems and equipment certification)

Performance Within 5G Cellular Environment

In collaboration with the FAA and RTCA, Honeywell has performed radio frequency testing on the KRA405B radar altimeter to assess its ability to meet its minimum operating performance specifications when subjected to radio frequency energy from 5G cellular base stations. The KRA-405B requires the installation of an external bandpass filter between the radar altimeter receive antenna and the radar altimeter receive input. The external bandpass filter reduces the unit’s susceptibility to interference from 5G base stations.

Aircraft using the KRA-405B radar altimeter with the external bandpass filter are able to obtain Alternative Means of Compliance (AMOC) to the FAA Airworthiness Directives 2021- 23-12 (fixed-wing) and 2021-23-13 (helicopters) that were introduced by FAA in December 2021. The bandpass filter is part number 68013467-001 and is available from Honeywell today. Contact us for for bandpass filter pricing and availability.