The US aviation industry is urging the Federal Aviation Administration (FAA) to push to mid-2032 a deadline for updating thousands of radio altimeters to withstand interference from 5G cellular signals.
The industry faces a massive and costly problem: spending billions of dollars to update altimeters in the next several years, before cellular companies begin using new radio bandwidth.
The US Federal Communications Commission in 2027 plans to finish auctioning spectrum in the 3.98-4.2GHz range, the “Upper C-band”, to cellular providers. But those transmissions can interfere with 58,600 radio altimeters fitted to some 41,000 aircraft.
In response, the FAA in January proposed requiring operators to update altimeters to be interference “tolerant”. It proposed a deadline between 2029 and 2032 for Part 121 operators – airlines – and two years later for other aircraft.
But an aviation coalition insists the sector needs more time – at least until mid-2032 for airlines and until 2034 for others.
In a 9 March comment to the FAA, the “Joint Aviation Community” notes the agency has yet to even finalise new altimeter technical standards.
Upgrades must then be developed, certificated, manufactured and finally installed on aircraft, says the group, whose members include Airlines for America (A4A), Allied Pilots Association, Aircraft Owners and Pilots Association, Boeing, Garmin, Gulfstream, the General Aviation Manufacturers Association, the National Business Aviation Association, the Regional Airline Association, RTX and Thales.
Many altimeters can be upgraded to comply with new standards – that work can likely be completed overnight. But other aircraft will need wholly new altimeters.
A 2029 deadline does “not adequately reflect realistic production and installation rates”, Lockheed Martin tells the FAA. It doubts altimeter manufacturers can meet production requirements, citing “supply chain constraints, including semiconductor availability and rare-earth element inventory”.
Parties note they had much more time – a decade – to meet a requirement for installing ADS-B (Automatic Dependent Surveillance-Broadcast) Out systems.
But powerful cellular trade group CTIA is urging the FAA not to extend its timeline, insisting the deadline should be 2029, which it calls “readily achievable”. The FAA should make the timeline “firm”, CTIA adds.
It is also how much flexibility the FAA actually has. President’ Donald Trump’s One Big Beautiful Bill Act requires the FCC auction the bandwidth by July 2027, and the Trump administration has made expanding 5G a leading priority.
Aviation stakeholders are warning that upgrading altimeters will cost more than the FAA’s $80,000-per-unit, or $4.5 billion total, estimate.
Indeed the Joint Aviation Community says updating each altimeter could actually cost $120,000. It also wants aircraft operators to receive reimbursements – an idea the FCC also floated.
“With the confidence that reasonable costs will be reimbursed, Part 121 operators can begin the financially daunting and logistically intensive process,” A4A tells the FAA.
This is the second recent instance of aircraft operators facing major 5G headaches. In 2023, the FAA set new altimeter standards and operating restrictions in response to cellular companies starting to use the 3.7-3.98GHz bandwidth.
Those requirements do prevent interference from the 3.98-4.2GHz range now set to be used.
