Assessment of C-Band Mobile Telecommunications Interference Impact on Low Range Radar Altimeter Operations

Using technical information supplied by the mobile wireless industry and radar altimeter manufacturers, this report provides a quantitative evaluation of radar altimeter performance regarding RF interference from expected 5G emissions in the 3.7–3.98 GHz band, as well as a detailed assessment of the risk of such interference occurring and impacting aviation safety. This process included testing of many representative radar altimeter models to empirically determine their tolerance to expected 5G interference signals; the development of interference models and assumptions to predict the received interference levels across a wide range of operational scenarios, such that they may be compared to the empirical tolerance limits; and a thorough study of multiple real-world operational scenarios for civil aircraft in which the presence of the expected 5G interference will result in a direct impact to aviation safety.

The results presented in this report reveal a major risk that 5G telecommunications systems in the 3.7–3.98 GHz band will cause harmful interference to radar altimeters on all types of civil aircraft—including commercial transport airplanes; business, regional, and general aviation airplanes; and both transport and general aviation helicopters. The results of the study performed clearly indicate that this risk is widespread and has the potential for broad impacts to aviation operations in the United States, including the possibility of catastrophic failures leading to multiple fatalities, in the absence of appropriate mitigations.