5G vs. Radar Altimeters

Ventucky Red

Ventucky Red

Pattern Altitude
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Jon
So what is all the "broo-ha' about AT&T and Verizon not playing nicie-nice with the FAA.. Aren't these analog integuments being obsoleted?
 
Ventucky Red said:
So what is all the "broo-ha' about AT&T and Verizon not playing nicie-nice with the FAA.. Aren't these analog integuments being obsoleted?
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They are not often used in GA airplanes but they are in transports.

Our ground proximity warning systems (GPWS) relies on radar altitude for several of its warning modes.

CAT II and CAT III approaches and autolands require radar altitude inputs.

Radar altitude inputs are used in numerous other systems and functions such as flaps and gear warnings and autothrottle logic.

The crash of Turkish Airlines 1951, a 737-800 in 2009, resulted when the autothrottles reduced power to idle at about 2,000' due to a faulty radio altimeter and the crew failed to recover prior to the aircraft stalling.

The crash was caused primarily by the aircraft's automated reaction, which was triggered by a faulty radio altimeter. This caused the autothrottle to decrease the engine power to idle during approach. The crew noticed this too late to take appropriate action to increase the thrust and recover the aircraft before it stalled and crashed. Boeing has since issued a bulletin to remind pilots of all 737 series and BBJ aircraft of the importance of monitoring airspeed and altitude, advising against the use of autopilot or autothrottle while landing in cases of radio altimeter discrepancies.

https://en.wikipedia.org/wiki/Turkish_Airlines_Flight_1951​
 
It is a bit of a puzzle. 5G for cell phones didn't happen overnight, and everyone knew what it was and when it was going to launch. It appears to me the FAA is changing their minds on what the potential danger could be if a 5G cell signal or radar altimeter system strayed too far from their assigned spectrums. From what I've read nothing has changed, no new evidence / data has come to light. So it sounds like the FAA is second guessing themselves, after initially being on board. That versus there being a real, newly discovered danger. Anyone know of new data showing something different?
 
WDD said:
It is a bit of a puzzle. 5G for cell phones didn't happen overnight, and everyone knew what it was and when it was going to launch. It appears to me the FAA is changing their minds on what the potential danger could be if a 5G cell signal or radar altimeter system strayed too far from their assigned spectrums. From what I've read nothing has changed, no new evidence / data has come to light. So it sounds like the FAA is second guessing themselves, after initially being on board. That versus there being a real, newly discovered danger. Anyone know of new data showing something different?
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I believe it's a new frequency/band that is being added for 5G. So yes, 5g is already deployed, but not on this band and it's very close to the radar altimeter frequency, hence the concern.
 
Not just transport, a lot of aircraft use them and in some cases aren’t allowed to fly with an inop RADALT.

E6291966-E27E-4E5F-B440-75C0B414B356.jpeg
 
I’m gonna guess Ma Bell owns more Legislators than the Airlines and those almost WOXOF lines of minimums may be going bye bye
 
WDD said:
That versus there being a real, newly discovered danger. Anyone know of new data showing something different?
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None of this is new. It's been a discussion topic for a few years. However, it took the US 5G companies to finally push things forward to make it front page. Personally I think the 5G companies thought they had better lobbyists. And while the EU appears to have a lesser issue with they're 5G rollout it is much different than the US version as they use lower power, no towers near airports, etc. But here is some of the latest info below. While the ADs, etc. affect the larger aircraft as noted above, it basically drops the hammer on all commercial helicopter ops as they tend to fly outside of normal airplane routes/locations. It will be interesting.
https://www.federalregister.gov/doc.../airworthiness-directives-various-helicopters
https://www.federalregister.gov/doc...ves-transport-and-commuter-category-airplanes
https://www.icao.int/safety/FSMP/Me...nel and IATA IFALPA 5G problem statement.pdf
https://www.rtca.org/wp-content/uploads/2020/12/Slides-5G-Interference-Risk-to-Radar-Altimeters.pdf
https://www.faa.gov/other_visit/avi...afety/safo/all_safos/media/2021/SAFO21007.pdf
https://rgl.faa.gov/Regulatory_and_...d16db10862587b4005b26fc/$FILE/AIR-21-18R1.pdf
 
Bell206 said:
None of this is new. It's been a discussion topic for a few years. However, it took the US 5G companies to finally push things forward to make it front page. Personally I think the 5G companies thought they had better lobbyists. And while the EU appears to have a lesser issue with they're 5G rollout it is much different than the US version as they use lower power, no towers near airports, etc. But here is some of the latest info below. While the ADs, etc. affect the larger aircraft as noted above, it basically drops the hammer on all commercial helicopter ops as they tend to fly outside of normal airplane routes/locations. It will be interesting.
https://www.federalregister.gov/doc.../airworthiness-directives-various-helicopters
https://www.federalregister.gov/doc...ves-transport-and-commuter-category-airplanes
https://www.icao.int/safety/FSMP/MeetingDocs/FSMP WG11/IP/FSMP-WG11-IP08_ICAO Flight Operations Panel and IATA IFALPA 5G problem statement.pdf
https://www.rtca.org/wp-content/uploads/2020/12/Slides-5G-Interference-Risk-to-Radar-Altimeters.pdf
https://www.faa.gov/other_visit/avi...afety/safo/all_safos/media/2021/SAFO21007.pdf
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgSAIB.nsf/dc7bd4f27e5f107486257221005f069d/379cfb187d16db10862587b4005b26fc/$FILE/AIR-21-18R1.pdf
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Hmm. Ma Bell and Bell Helo into the Thunderdome:devil:
 
Love the info you can pick up in this place
 
SkyDog58 said:
Well, I do believe that autoland depends on a Rad Alt to operate so... yes.
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I can't post a link as I'm new here. But I did find an article from Skies Magazine on Garmin Autoland from March of 2021 which stated "Carr also confirmed that the minimum requirement for [Garmin style] Autoland to designate an airport runway as good to go is that it have a GPS approach with a vertical component...". I found a Stack Exchange (Aviation) post that seemed to come to the same conclusion.
 
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