5G airline clusterf***

From William Gallagher's "Carriers agree to another 5G delay around US airports" posted Wednesday on AppleInsider:

AT&T and Verizon are to postpone rolling out 5G near certain airports in the US, following further complaints from airline CEOs.

As the CEOs of Delta, United, and other airlines claim that 5G expansion would ground planes and cause a "catastrophic" economic crisis, both AT&T and Verizon are to limit their planned rollout of the service.

According to BBC News, AT&T says it is "temporarily" halting the rollout at a "limited number of [cell] towers around certain airport runways."

FOB Bartley Yee's take:

Clusterf***.  I do not understand how and why the aircraft manufacturers, airlines, and the FCC/telecoms have not simply and strictly tested the radio altimeter systems in the specific 5G band rich environment in tests or in real situations to determine if there really are any issues.  As the telecoms have said, there’s been two years to evaluate this issue and determine what needed to be checked, verified and/or modified.  The threats of airline disruptions are bullying tactics underlining the failure of the FAA and aircraft/instrumentation and airline companies to do their due diligence in determining if there is any validity to their vague claim that aircraft would be truly affected.

Meanwhile, the telecom claims that 5G is used already in other countries doesn’t quite ring true unless they're using the exact or similar frequency spectrum bands that concern domestic flight systems.

My take: For many years, I've been turning off my iPhone's airplane mode long before landing. Haven't crashed a plane yet.


  1. Jerry Doyle said:
    This is a major embarrassment to the administration and a slap in-the-face to a president who publicly had to thank the carriers from proceeding forth with their roll-out of 5G until he can get his Executive Branch Office to reconcile the disagreement between two federal agencies. These agencies had two years to settle their differences and did not do so while knowing what the stakes were if they failed to do so. Heads should role in these two federal agencies and the buck stops with the president who had to be cognizant of the slow train wreck occurring over at the FAA and FCC. Where was the head of the Transportation Department throughout this process? Secretary Pete Buttigieg had to be aware of the developing problem and did not intercede. The carriers’ CEOs have a right to be hoppin’ mad.

    January 19, 2022
    • Bart Yee said:
      @Jerry While I agree the current administration is stuck dealing with trying to get this issue resolved between two competing major agencies and industries, my notes from below suggest the issues have been considered since at least 10 years ago, so three administrations prior were involved well. The last administration had well documented issues of deregulation efforts and weakening of both the FCC (deregulation to allow telecoms faster / easier 5G rollout, auctioning of 5G bandwidth, and the controversial attempt at reducing or eliminating section 530 liability protections of social media companies accused of discriminating against conservatives) and FAA (multiple issues including the Boeing 737 Max certification problems, airline deregulation and passenger rights, air traffic control, etc.)

      Both prior admin appointed agency heads were industry veterans (FCC – Verizon and Justice Department, FAA – at first floated The President’s personal pilot, then appointed Delta Airlines Safety executive) but of course heavily beholden to the administration’s agenda and IMO somewhat chaotic style of loyalty first and interagency conflicts.

      So yes, IMO, the current administration is having to sort this all out between agencies and industries while having to combat a domestic and worldwide pandemic amid an explosive inflationary rebound recovery and international tensions from two other major superpowers. And of course difficulty in getting legislation through a divided Senate.

      As some would say for the new administration “you knew the job was dangerous when you took it”. IMO, I would have had little to no confidence on resolving the above issues if the alternative administration were still in place. And that’s about as far as I should go.

      January 19, 2022
    • Alan Birnbaum said:
      My former mayor, ” Mayor Pete” ( South Bend) only significant ‘achievement’ was his smart streets. It was years behind and over budget. It essentially just slowed traffic and improved bike lanes. In conclusion, it was a failure in its goal to improve downtown business. I’m not surprised at the his lack of interest in 5G project. He is very pleasant in person, though.

      January 19, 2022
  2. Bart Yee said:
    This comment in a similar 9to5Mac article’s comment section seems to shed some light, author quoting from a 2011 study. As usual, it’s all about the money:

    “Eric Swinson -16 hours ago edited
    Also in Europe and Asia they use a fraction of the output wattage that Carriers in the states do. They are geared to denser deployments using more towers and base stations. Whereas in the states a tower has to cover more area so it outputs more power. There are legitimate reasons for the FAA/airlines to be concerned, but the FCC is more than capable of assessing this and I would defer to their expertise before going “Chicken Little” on potential threats to safety as the airlines are doing now. The FCC overseas all aviation radio services including the radar altimeters in the US so it is certainly in their wheelhouse.

    What this probably boils down to is the $80K a piece (in 2011 dollars) it will cost to replace the altimeters. There was a briefing about this is 2011 that estimated in the US it would cost 2.2 Billion to replace them in all 27,350 commercial planes. It seems that while the altimeters work at a center frequency of 4300 Mhz, they can drift up to ~200 MHz either way depending on temperature and calibration. Which would put them in the 4200-4220 or 4380-4400 MHz range the FCC wants to use for 5G. The FCC looked at that data, did their own testing and determined the minimal interference was an extreme edge case and less likely to occur than other more common onboard sources of interference and still not enough to cause errant readings. The FAA disagreed and cited crash and near crash investigations that noted bad altimeter readings, yet in 10 years did nothing to rectify what they believed would be a future conflict nor have they addressed the elephant in the room that radar altimeters may simply have a design flaw and their integration with autopilot systems may be risky in general.

    From the 2011 report:

    “All altimeters supplied by Honeywell are placed essentially in the middle of the 4.2 – 4.4 GHz band and use small bandwidths at the edges of the band to provide room for frequency drift. The majority of the several thousand altimeters sold by Honeywell alone over the last two decades do not use closed loop frequency control or crystal oscillator based precision stability reference oscillators. The NTIA should therefore expect that it is entirely possible to expect altimeters from Honeywell and other suppliers to routinely occupy the band edges being considered for re-use as communications applications.”

    So it’s not that the 5G networks tread on the altimeter’s frequencies, it’s that the altimeters could tread on the 5G networks’ frequencies. I would like to add that prior to 5G other countries have deployed WiMAX at the 4200 MHz spectrum at much higher power outputs than current 5G deployments with no known aviation safety issues.”

    January 19, 2022
  3. Fred Stein said:
    2 years? They’ve had much more time. 5G has been long in the making.

    January 19, 2022
    • Bart Yee said:
      Agree, see my extracted comment from commenter to 9to5Mac article above.

      January 19, 2022
  4. Bart Yee said:
    Now 27,000+ altimeters in commercial aircraft is one thing, about $2.2B in costs and even more in time to fix or replace.

    But what about another class of aircraft (not sure if included in above numbers), rotor craft or helicopters? They fly at much lower altitudes,, traverse urban areas way beyond the boundaries and corridors suggested for airports while carrying out important functions like law enforcement use, vehicular traffic reporting, medical rescue and evacuation transport, major fire suppression, and of course military helicopter operations. I came across two articles in a quick search regarding anticipated problems and details from helicopter industry tech experts from Sikorsky (div of Lockheed Martin), and Honeywell, the manufacturer of most of the radio altimeters in use by Boeing, Airbus, Sikorsky and other aircraft. While discussing the problem, they blame 5G and telecoms for being too close to radio altimeter frequencies while not always acknowledging the vagaries or drift, and / or the inadequate frequency lock / filtering or discrimination of their own instrumentation designs:

    “Seth Frick, a radar systems engineer with Honeywell, said altimeters altered by 5G signals could produce a disparity of several feet to thousands of feet from a helicopter’s actual altitude, depending on the distance from a tower.

    “You could have things bumping around plus or minus 50 feet, 100 feet, to complete loss of function … to sustained erroneous output that is not indicated as erroneous, which could be hundreds of feet, or thousands of feet away from the true altitude,” Frick said during the HAI webinar. Certain altimeters could see relatively little or no interference from 5G, while others could be rendered completely useless, he added.

    “I don’t know if there’s any cases where we can say there is absolutely no interference,” Frick said. “There certainly are altimeter models that we think we have data that shows they perform very well and are very robust. Any errors, either undetected, erroneous altitude output or loss of function for those particular models is going to be extremely unlikely. But there’s a whole lot of other cases where there is a likelihood of interference, but it kind of depends on how the aircraft is being operated, where you are relative to the 5G towers, and so on. So, it’s not really a binary thing of this altimeter model is susceptible, this other model is not.”

    January 19, 2022
  5. Bart Yee said:
    Another helicopter article with details and my emphasis:

    During a webinar held Jan. 13, HAI’s Director of Government Affairs, John Shea; Seth Frick, radar systems engineer, Honeywell Aerospace; and Nick Kefalas, a Lockheed Martin technology fellow at Sikorsky Aircraft Corp., addressed the potential disruptions of 5G’s rollout.

    Frick stated that Honeywell has been conducting “substantial testing” on all of the altimeters models they produce to discover what 5G’s impact will be.

    “The behaviors we observe in the laboratory setting do vary by model to model. But generally, we’ve observed everything you can imagine,” Frick said.

    Some of the behaviors recorded have been altimeters “becoming noisy,” putting out altitude misreadings of plus or minus 50 to 100 feet. Other disruptions have been more severe, with altimeters giving no reading at all or giving erroneous readings of hundreds and thousands of feet off true altitude. Compounding the issues, sometimes the altimeters do not recognize that the information they are displaying is wrong and provide no warning to pilots.

    Frick noted that in real-world scenarios, they expect things to be more dynamic than can be represented in the laboratory.

    “There’s going to be a range of different impacts,” he continued. “Our conclusion has been, based on our testing, that there’s not really any kind of failure mode that we could safely rule out. You could have detected faults, loss of function. You could have undetected erroneous output, which could constitute hazardously misleading information depending on how that altitude output data is used onboard the aircraft.”

    There are two primary modes of interference that are of concern. Frick said they are referred to as front door and back door coupling. As he explains, 5G networks put out high-powered signals in their own frequency band, separate from the altimeter band. However, the altimeters don’t have perfect filtering for these bands built into them, meaning they pick up some of the 5G network’s signals regardless.

    Frick continued that 5G networks will also leak out much lower levels of interference directly into the altimeter band. He said that the former, the high-powered signals, appear right now to be what causes the most altimeter disruptions.

    One solution to the problem is to increase an altimeter’s filtering. Though it is not a quick fix. Retrofitting altimeters to filter the 5G signals is a process that can take anywhere from six months to a year. And not all altimeter models will be able to be retrofitted and will need to be replaced altogether.

    It does not help, Frick added, that altimeter standards have not been updated since the 1980s – well before the introduction of cellular communications. Efforts are currently underway to update standards for the modern age, though.

    January 19, 2022
    • Bart Yee said:
      “ In the meantime, the FAA is offering the same guidance to rotorcraft operators as they are to those of their fixed-wing brethren – guidance based on protection zones around 5G towers and airports. These zones are two nautical miles out from an airport’s runway threshold. If a 5G tower’s signal crosses into these protection zones, a pilot will need an alternative method of compliance (AMOC) to land.

      Yet, this guidance is of little help to heliport operators, which do not yet have similar guidelines, or rescue operations that may be flying and landing in unconventional areas to complete their missions.

      “The NOTAMs that were released today cover both airspace procedure and aerodromes. If you are, say, in the New York Metropolitan Area where you have JFK on the south of the island and LaGuardia on the north, there may be zones within that area that you may have to drop below certain altitude, or there will be an altitude of a ‘no-go’ zone,” said Kefalas. “We have seen information that shows that the lower you get, the better your performance is. So, all that will have to be weighted in the way operations are conducted going forward.”

      January 19, 2022
  6. “…altimeter standards have not been updated since the 1980s – well before the introduction of cellular communications. Efforts are currently underway to update standards for the modern age…” (AviationPros.com 1/14/22)
    Apple offers updates to most hardware & software several times a year, every year. Changes to standards like Wi-FI and Bluetooth are debated and implemented regularly. Updates to standards for commercial transport aircraft navigation devices haven’t occurred in ~40 years?
    Why don’t we cut to the chase? Stick a 5G iPhone running a regularly updated, secure altimeter app on top of the radar altimeter. Problem solved.

    January 21, 2022

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