FAA Proposes New Radio Altimeter Regulations, Costs Could Soar

The Federal Aviation Administration (FAA) has proposed new regulations that could require United States aircraft operators to upgrade up to **58,600 radio altimeters**, potentially costing more than **$4.5 billion**. This initiative is part of the government’s transition to the **5G spectrum**, aimed at minimizing interference that could compromise aviation safety.

As detailed in the Proposed Rule published in the **Federal Register**, this mandate is included in the **One Big Beautiful Bill Act**. Section 40002 of this legislation directs the Federal Communications Commission (FCC) to conduct competitive bidding for a minimum of **100 megahertz** in the **3.98-4.2 gigahertz band** (Upper C-band). The FAA’s proposed regulations, detailed on **January 7**, stipulate that all aircraft radio altimeters must meet new performance criteria to withstand interference from adjacent wireless signals.

The performance requirements would apply primarily to aircraft operating under Parts 121 and 129, as well as those carrying **30 or more passengers** or with a payload exceeding **7,500 pounds** (approximately **3,400 kg**). These aircraft must comply with the new standards by a deadline set between **2029 and 2039**, depending on equipment availability and retrofitting capabilities. All other aircraft will be required to meet these performance standards within two years of the rule’s finalization.

Public comments on the proposed regulations will be accepted until **March 9, 2024**. In response to the announcement, **Airlines for America** stated: “We have been working collaboratively with the telecommunications industry, the FAA, and the FCC to identify solutions that ensure our nation’s airspace remains safe while allowing the spectrum to be used.” The organization indicated it would evaluate the proposal closely before submitting formal comments.

Safety and Technological Challenges

A primary goal of the new regulations is to limit interference in wireless signals. Radio altimeters rely on accurate data received from ground systems to function effectively. The FAA has indicated that various users may experience faint reflections from the ground, which can result in erroneous readings or nuisance alerts. Such interferences could lead to dangerous situations where pilots cannot accurately assess their surroundings, endangering passengers and crew.

The enhanced altimeter systems are expected to improve capabilities for enhanced vision operations, terrain awareness, wind-shear detection, and traffic collision avoidance. The urgency for these upgrades stems from previous decisions made during the Trump administration, which opened additional spectrum for bidding as a means to generate revenue from licensing fees.

The FAA estimates that retrofitting aircraft with interference-tolerant altimeters may cost upwards of **$4.5 billion**, which translates to around **$424 million** annually when calculated at a **7%** discount rate over a **20-year** period. Given the critical role altimeters play in navigation, these enhancements are seen as essential for maintaining flight safety in a rapidly evolving technological landscape.

Background and Previous Findings

Concerns about 5G technology and potential radio interference are not new. In **2021**, European aviation regulators investigated similar issues and concluded that interference was not a significant risk. Meanwhile, the FAA is set to replace existing radio altimeter systems by **2024**. By **September 2023**, it was determined that the risk of **5G interference** to the U.S. airline fleet had been effectively mitigated.

In an analysis published by **AeroTime**, it was reported that out of **625 incidents** reviewed, **118 events** indicated potential interference with C-band radio, which included display errors and nuisance alerts tied to radio altimeter inputs. As the FAA moves forward with these proposed regulations, the aviation industry faces substantial financial implications alongside the imperative of ensuring safe and reliable air travel.