5G Deadline Looms, FAA Urges Action


In two weeks, AT&T and Verizon will turn up the power on 5G signals around some of the country’s biggest airports and the FAA is imploring airlines to harden vulnerable aircraft against interference with their radar altimeters. The telecoms agreed to soften the introduction of 5G in January at some airports in the face of claims by airlines that it would seriously disrupt air traffic. That deal expires on July 5 and the companies appear to be going ahead with the full rollout. The 5G signals operate on the C-Band and the frequencies are close to those used by radar altimeters to measure aircraft height in the final stages of instrument approaches. Reuters got a look at a letter from FAA Acting Administrator Billy Nolen and he seems worried about potential disruptions.

The FAA has told operators of vulnerable aircraft to retrofit them to prevent interference but apparently some have not. Nolen told the airlines the telecoms are working with the FAA to minimize impact but the FCC, which governs the airwaves, has a part to play, too. “Without additional action by the FCC to cap transmissions at currently attainable power levels, the prospect of additional disruption remains and we are not in any position to offer assurances,” Nolen wrote. Replacing and modifying radar altimeters is happening but won’t be done until the end of this year at the earliest. 

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

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  1. What a lot of crap. I don’t understand the so called problem with 5G? Australia has as Far as I know no problem and I don’t see any where else in the world where this problem exists. Is this by miss adventure because of there being no real problem. Typical FAA miss the point of any possible advance being, it Tech but who really knows, and why is it taking so long to agree there is no fix because there is no problem. Costs to who??

    • Everywhere else in the world (that I know of) caps power at the large airports, and even has directional antennas keeping the signals low to the ground. The US has (or soon will have) none of that.

    • See Brian’s answer below. Other country’s have a different frequency for 5G that is not as close as ours for the radar alts

  2. This is an FCC created problem. The FCC was told this was an issue an ignored it in auctioning off the licenses for the spectrum.

    Do not blame this on the FAA. The FCC went through this same situation about 10 years ago when they auctioned off GPS guard band spectrum and were about to authorize it for high powered terrestrial cell phone use. That was dis-railed by a combined effort of the military, civilian, ag, and maritime alphabet groups then, but the ashes of that mess have arisen and they are attempting to get approval for the same failed plan. If they are successful and with this administration, which is even more friendly to corruption than the 2012 administration, we can kiss GPS goodbye.

    All of us must remain vigilent particularly where RF (FCC) and aviation (FAA) are concerned and interact.

    • Thankyou for some facts.

      (Though ‘corruption’ is glib, doesn’t happen today – contributions to favourite charity may occur. Mostly what happens is someone signing a song of harm if don’t do what lobbiest wants – in this case Internet access may be a pitch.
      Besides just irresponsible ignorance – spelled ‘bureaucrat’ and ‘politician’.)

  3. This really is a technical problem. A properly designed receiver will reject out-of-band signals and a properly designed transmitter will limit its emissions to the assigned band/channel. The real problem is that older RADAR technology used excessively-broad receivers because the transmitters were not well controlled. (Magnetrons, Klystrons, and Gunn diode oscillators are not known for their frequency accuracy.) So long as there were no other signals around, this worked fine. Anyone who has worked on older RADAR altimeters knows just how broad those designs were. Some of those designs are pushing 50 years old. (I first flew CAT-3 autoland depending on RADAR altimeter in the DC-10 back in 1976 and I bet some of those RADAR altimeters are still flying and controlling autoland.) They didn’t design them with the idea that there would be any other emitters in the whole band so they opted for designs that took advantage of that to provide a high level of accuracy, repeatability, and reliability with the technology then available. Unfortunately those old designs are just not up to the needs of the current environment.

    Today we can build a LOT better. We can have the accuracy, reliability, and repeatability while including the ability to reject undesired signals in the same band. 5G legitimately uses spectrum and does not transmit into the channels that are assigned for RADAR altimeters but those older RADAR altimeters which were designed with broad receivers because their transmitters were not that accurate, are susceptible to the close-in signals from 5G. It really is time to pull those old boxes from the avionics bay and slide in something newer and better. Really.

    • $. Chances are those older units will not be replaced due to whether the cost and training for cat ll and cat lll for that aircraft are worth it. Don’t need a radar altimeter for cat l ILS minimums. Even FedEx has phased out their DC10s.

      • Auto-land is used by some carriers for lower CAT I approaches. This includes many airports that don’t have CAT II or III minimums. The old radar altimeters should be replaced.

  4. Brian’s comments are spot on about the core technical problem. However, given the regulatory environment for development and certification of avionics, the costs of upgrading, and the fact that we have a significant fleet of aircraft still flying with the older equipment, operated by firms trying to function in an often-low-margin industry, I do have a problem with FCC just ignoring FAA’s repeatedly stated concerned. It feels like industry capture of FCC at the expense of flight safety. There will end up being some operators and flights that simply can’t fly routes with very low conditions, and that will result in travelers sleeping on the floor of airports. When the agencies squabble, we need a decision at the presidential level.

  5. You build your house in a rural agricultural area and relesh the unobstructed view out the front windows, only to find a 360-unit development going up across the road only a few years later.

    You try to stop it, using the theory that even though it isn’t your land, you have the right to prohibit construction on it because it was an open field when you built there. Incredible though it may seem, your protest fails.

    • Irrelevant analogy.

      ‘You’ are trying to use control someone else’s property at no cost to yourself.

      The question in this thread is shared air.

  6. The FAA says that carriers should upgrade their equipment, but when the carriers ask what equipment is approved or even acceptable in this new 5G environment, the FAA goes silent.

    Strange that no upgrades have been accomplished.

    Ready, Fire, AIM!

    • Uh, equipment has been tested – read the RTCA report!

      Airplane use of radalt information has been evaluated by aircraft manufacturers in at least many cases, and results published.

      Both aspects must be integrated, as different aircraft use radalt information differently.

  7. According to another publication, it looks like the FAA and the 5G companies have agreed to an extension to the lower power at certain airports