Telecoms Reject Another 5G Delay, Offer To Modify Airport Deployment (Updated)


Verizon and AT&T say they’ll turn down the power of 5G broadband signals near major airports of their choosing for six months but otherwise the rollout of the much-anticipated system will go ahead as planned on Jan. 5. In a scathing letter to Transportation Secretary Pete Buttigieg and FAA Administrator Steve Dickson released by The Wall Street Journal on Sunday, AT&T CEO John Stankey and Verizon’s Hans Vestberg chided the government officials for what they characterized as an eleventh-hour request to prevent widespread flight restrictions when they’ve had at least a year to prepare for 5G.

The FAA has concerns that 5G signals that operate in a frequency range as close as 220 MHz to the band used by radar altimeters will disrupt the function of some altimeters. The devices accurately measure the final 200 feet of altitude in aircraft conducting instrument approaches and using autoland. It has prepared NOTAMs banning the use of radar altimeter-dependent avionics and procedures that will be issued anywhere it believes the 5G signals could make radar altimeters unreliable.

In a letter to AT&T CEO John Stankey and Verizon’s Hans Vestberg on Dec. 31, Dickson and Buttigieg implored the executives to give them another couple of weeks to pull together a plan they hoped would blunt the worst potential effects of unleashing 5G. T-Mobile also offers 5G service but doesn’t use frequencies near the radar altimeter band.

But the telecom executives responded they they’ve already accommodated the aviation community’s concerns with a costly one-month delay of the rollout and they’re not prepared to delay it any longer. They did, however, offer to modify the rollout to implement modifications similar to those imposed by the French government on 5G providers surrounding major airports there.

“That approach—which is one of the most conservative in the world—would include extensive exclusion zones around the runways at certain airports,” Stankey and Vestberg said. “The effect would be to further reduce C-band signal levels by at least 10 times on the runway or during the last mile of final approach and the first mile after takeoff.” The modifications would be left in place until July.

Dickson and Buttigieg wanted the two weeks to draft regulations to support phased-in implementation of 5G near so-called “priority airports” across the country. After the two weeks are up, the 5G rollouts could go ahead everywhere except in “buffer zones” around those priority airports. The goal was to prevent a massive domino effect of delays and cancellations if weather requires the use of radar altimeter-reliant equipment and procedures at those key facilities and they are not available. The agency also wants to expedite Alternative Means of Compliance (AMOC) that will allow at least some aircraft with interference-resistant radar altimeters to operate where 5G is present. 

“From the beginning of our discussions, our overarching goal has been to protect flight safety, while ensuring that 5G deployment and aviation operations can co-exist,” the letter says. “We believe this proposal advances this goal and avoids substantial disruptions to aviation operations—and to the flying public—in the short term.” The letter does not touch on what the long-term solution(s) to 5G interference might be but pundits speculate it revolves around who will pay to retrofit older aircraft with more modern altimeters that are shielded against the interference.

Stankey and Vestberg responded that they were not about to turn over control of the pace and structure of the rollout to the FAA when they already have the full blessing of the Federal Communications Commission (FCC), the agency responsible for assigning radio spectrum. The telecoms have always claimed the interference fear is overblown and noted that U.S. aircraft routinely fly to France with FAA approval despite the existence of 5G there and in 40 other countries.

The FCC has also maintained that there is no evidence the interference is an issue. That’s in direct disagreement with the findings of a study by the Radio Technical Committee for Aeronautics (RTCA), which first flagged the issue more than a year ago. It said there are tens of thousands of older radar altimeters at risk of interference from 5G.

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  1. The average American has no idea why this is an issue. All they care about is getting the faster speeds and service on their phones. Until flights are actually cancelled or diverted due to this issue (or better yet some Congressperson not being able to land at DCA) nothing will change. Most of the planes affected by this are pt121 airliners. Very few pt135 charters do cat II or even cat III and RNP approaches due to the additional cost of equipment and training involved for the actual few times weather is bad enough to require these approaches. Remember the airlines got a 5 year extension on ADS-B equipment deadline due to there are some older planes that do not have GPS. The airlines wanted more time to phase them out since equipment costs were not worth it to them. Can’t comment on helicopter use as I am not a helo pilot.

      • TAWS does not use radar altimeter, it is GPS based. GPWS on the other hand could be an issue at non- towered, non radar approaches. But for a Cat I ILS with a 200ft 1/2 mile-1800rvr minimum, radar altimeters are not part of determining the missed approach altitude (decision height). And doing those approaches at a towered field you have the tower monitoring that approach.

          • My mistake, RA is part of class A TAWS only. The only part of a CAT I ILS the GPWS is part of is a warning if more than one dot low on glide slope. Otherwise radar altimeter is not part of a CAT I ILS, determining decision height, in fact on my airplane it is a MEL-able item not effecting CAT I ILS minimums since it is not used for DH. Another publication has reported that the FCC/FAA dispute may go to court soon.

  2. Real World ramblings – As I spent part of the weekend fitting notch filters to the household Digital Over the Air antennas in the house to mitigate the effects of the new 5G mini tower on the pole in the street that is impinging on the signals. Sure – strictly we are on different frequencies – but someone is blasting into the TV signal space with a “leaky” cell tower. If the cell tower that is a quarter of a mile away is a problem – then I suspect the radio altimeter issue is real.

    I note the Canadians simply banned 5G towers around any of their 26 affected airports (though based on US data / research).

    A little digging around – the self-driving car folks have issues with the same sort of thing – needing cars to be able to signal each other with utter reliability in order to deconflict from each other – but running into other nearby frequencies interfering with the signaling.

    At issue (apart from the Benjamins that the cell companies paid to use frequencies) is emergent and “nimble” new technologies running into “last-gen” certification standards and equipment which if not set in actual stone – are set in sub-zero molasses. You can’t “just fit” some notch filters to the radio altimeters and hope for the best.

    How long did we get to introduce a new standard like ADSB?

    How long did/are the part 121 operators get to re-equip to avoid 5G cell towers? Does the equipment even exist?

  3. up till now the responsibility is with those with the transmitter. If my HAM radio, CB, WIFI etc. interferes with your radio, TV, etc. it’s MY responsibility or the manufacturer of the transmitting device to solve the interference problem. Look at the labels or owner’s manuals of your two way radios, cell phones, wireless mics, possibly even your microwave and see what it says.

    • Well, no, not exactly. There is a big difference in whether the interference stems from a licensed or unlicensed emission. To use licensed Ham radio as an example, if you as a Ham interfere with another service, such as TV reception, you have the responsibility to insure the interference is not due to a fault in your equipment. Assuming your signal is “clean”, although you are encouraged to work with the TV owner to resolve the issue, it’s the ultimate responsibility of the TV owner to fix the problem. This is not to say politics will not trump legal if you are a ham in an apartment building who is pi$#ing off 30 close neighbors. 🙂

      The rules for unlicensed devices are different. These are the ones which come with warnings that say something like “may not interfere” and/or “must accept interference”.

  4. “Stankey and Vestberg responded that they were not about to turn over control of the pace and structure of the rollout to the FAA when they already have the full blessing of the Federal Communications Commission”

    When Stankey and Vestberg’s G5 is delayed getting them to their ski vacation, they may change their tune.

  5. We were vigilant and aggressive in defending the incursion of cellular terrestrial service on the GPS bands several years ago (Lightsquared), but we also had the Pentagon, the Ag Department, the Transportation Department (with real leadership), the farm lobby, and the aviation lobby, on our side. It took this powerful coalition to stop the FCC, a major contributor to Obama/Biden administration from disrupting GPS nationwide. How did the FCC come to authorize that abusive spectrum assignment?
    Same way. The auctioned off ultra-low power designated GPS guardband frequencies to a private individual at a very low spectrum auction price. VZV and ATT did not bid because they knew! that spectrum could not be used for terrestrial purposes without destroying nationwide GPS coverage. Lightsquared argued that they wouldn’t interfere or aircraft, tractors, cars, etc could be refitted with tanks to strip out their sideband interference, claiming “unlicensed GPS receivers” were defective. Although Harbin/Lightsquared failed and the FCC/Obama/Biden were stopped, it showed VZV/ATT the way. And here we are.

    So, what to do about it? STOP auctioning spectrum and return the allocation to the RF engineers and physicists who understand the technical issues.
    Return the FCC to a technical agency and eliminate the political/revenue generation functions. (Fat chance).

    To solve the present issues: No Cat II/III approaches and GPWS does use Radio altimeters, so reset the MEAs to account for its low, eliminate RNP from the FAA’s vocabulary with all that it implies. The cost of air transit and diversions will go up orders of magnitude so my daughter can plan videos on her 5G phone. So be it.

    Next, the AD will turn into an EAD and require retrofitting of RA to re-enable the above. The power output of RA is generally low (40 mW) but the “new” RA can go as high as 5 W or even 500 W in some areas. Do it. And fingerprint the transmitted signal with tones/modulation to permit clear identification of the received signal. That will disrupt ground based 5G in the vicinity of glideslopes and approach paths and preserve aviation signal safety. Go back to requiring all 5G equipment on board the aircraft be turned completely off from TO/LDG-Taxi, or maybe leave it on and a 5 W (or 100-500W) signal may completely overload their cheap front ends and make them useless on board. The RA antenna is a non-directional emitter.

    Perhaps then VZV/ATT and the FCC will get the idea it is better to cooperate and coordinate that go to war. Unfortunately there will always be Harbin-like venture capitalists to “disrupt” everyone to make a cheap buck. That we will have to live with until we return to sanity. (unlikely).

  6. If 5G rollout is such a bad thing for aviation I’m sure none of you will ever upgrade your phone to 5G service just on principle, right? Didn’t think so.

    The vast majority of users affected will be 121/135 operators. They’re just going to pass the cost of upgrading avionics and cancelled/diverted flights along to the consumer. AOPA isn’t losing their mind because quite frankly it doesn’t have much impact on GA. Do any of you know anyone who has an RA in their GA aircraft that is susceptible to 5G interference? I sure don’t.

    The radio spectrum is only going to get more crowded in the future and I think you’ll see more of these issues pop up over time. The Aviation sector will be more affected than most because the technology in some of our airplanes is 30+ years old and wasn’t designed to work with such a crowded bandwidth. The FAA is going to have to lean forward with new technology.

  7. My pop corn is ready to watch the law suits that will fly if any crashes remotely could have been prevented by a radar altimeter… and the phone companies have disabled an aircraft safety devise…
    Glad to see the phone companies clambering to be sued.