14 CFR · Part 91
14 CFR § 91.220
Radio Altimeter Systems.
After October 31, 2034, unless otherwise authorized by the Administrator, no person may operate an aircraft in the airspace of the 48 contiguous United States and the District of Columbia with a radio altimeter unless the radio altimeter system meets the performance requirements of paragraph (b) of this section.
The radio altimeter system must operate at an altitude of 0-500 feet above ground level in the interference environment defined in table 1 of this paragraph:
Table 1 to Paragraph (b)
| Frequency range (MHz) | Power flux-density, single polarization, root mean square (dBW/m²/MHz) |
|---|---|
| 3000 ≤ f < 4000 | 9.5 |
| 4000 ≤ f < 4100 | 9.5 |
| 4100 ≤ f < 4150 | 9.5 |
| 4150 ≤ f < 4160 | 6.5 |
| 4160 ≤ f < 4170 | −1 |
| 4170 ≤ f < 4180 | −7 |
| 4180 ≤ f < 4190 | −17 |
| 4190 ≤ f < 4200 | −34 |
| 4200 ≤ f ≤ 4400 | −82 |
| 4400 < f ≤ 4410 | −33 |
| 4410 < f ≤ 4430 | −21 |
| 4430 < f ≤ 4440 | −8 |
| 4440 < f ≤ 4450 | −1 |
| 4450 < f ≤ 4460 | 6.5 |
| 4460 < f ≤ 4500 | 9.5 |
| 4500 < f ≤ 4600 | 9.5 |
| 4600 < f ≤ 5600 | 9.5 |
Referenced By
Interpretations of This Section (1)
Documents that cite this section, found in their catalog metadata or text. Listed by date, not by significance.
Reflects the eCFR edition current as of September 29, 2026. Retrieved from ecfr.gov on October 16, 2026.
Primary Source