The FAA has signed a final rule mandating radio altimeter retrofits. The rule requires interference-tolerant units on aircraft flying in United States airspace. It was signed on 24 July 2026 and is scheduled for Federal Register publication on 31 July 2026 as document 2026-15585. Docket FAA-2025-5666 opened as a notice of proposed rulemaking in January.
Scheduled airlines and larger foreign carriers must comply by 30 December 2030. Part 135 charter, Part 91K fractionals, and Part 91 aircraft already fitted with a radio altimeter have until 31 October 2034. Most large-cabin and super-mid business jets rely on the units for ground-proximity warning, autothrottle and Emergency Autoland.
The FAA counts about 58,500 units on 40,700 civil aircraft in scope. Per-unit retrofit cost sits between $80,000 and $120,000. The total civil bill lands between $4.49 billion and $7.2 billion. An FCC reimbursement scheme, funded from auction proceeds, will cover some operator costs.
The rule pairs with an FCC Report and Order adopted on 22 July 2026. That order opens 160 MHz of Upper C-band spectrum between 3.98 and 4.14 GHz to terrestrial wireless use. Combined with the Lower C-band already in service, 5G operators gain 440 MHz of contiguous spectrum. Buffer spectrum, transmission power caps and tower-height limits accompany the release.
Owner action turns on individual aircraft fit. NetJets, Flexjet, VistaJet and other Part 91K fractionals fall within the 2034 window. Charter operators under Part 135 face the same date. FreeFlight Systems and Collins Aerospace already sell 5G-tolerant units with existing supplemental type certificates on select platforms.
Source: FAA final rule 2026-15585, Federal Register public inspection 29 July 2026; Aviation International News; Aviation Week Network; AeroTime.