{"id":16320,"date":"2021-12-09T06:28:31","date_gmt":"2021-12-09T11:28:31","guid":{"rendered":"https:\/\/ops.group\/blog\/?p=16320"},"modified":"2021-12-15T10:05:22","modified_gmt":"2021-12-15T15:05:22","slug":"us-5g-rollout","status":"publish","type":"post","link":"https:\/\/ops.group\/blog\/us-5g-rollout\/","title":{"rendered":"Is the 5G rollout a new threat to aircraft safety?"},"content":{"rendered":"

The FAA issued a statement on Dec 7 regarding the expansion of 5G networks across the US, and its impact on aviation. It doesn\u2019t sound good – which is something folk have been saying for a while now\u2026<\/p>\n

What’s the background?<\/h4>\n

5G is being rolled out across the US in the form of massive antennas. No issue so far. The problem comes in when they turn them on because they use frequencies which are part of the \u2018slice\u2019 of radio spectrum usually reserved for GPS signals.<\/strong> Which means they will probably interfere with those signals, and disrupt the equipment in the aircraft utilising those frequencies.<\/p>\n

That equipment concerned are\u00a0Radio Altimeters<\/strong> which, as we all know, are fairly critical to certain operations. Some big accidents have been attributed to malfunctioning Rad Alts like Turkish Airlines Flight 1951<\/a>.<\/p>\n

Radio Altimeters transmit on frequencies between 4.2GHz and 4.4GHz,<\/strong> while the 5G network will use a C-Band range of\u00a03.7GHz to 3.98GHz.<\/strong><\/p>\n

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A larger telecommunications base station.<\/p><\/div>\n

Why the concern?<\/h4>\n

The big problem in all of this is the lack of information on how much interference\u00a0<\/strong>will actually occur.<\/p>\n

It\u00a0is not clear which airports will be impacted or to what degree equipment might be disrupted because it depends on the location and the strength of signals. While the RTCA (Radio Technical Commission for Aeronautics)<\/a> has conducted measurements and found that high levels of inaccuracy and outright failure<\/strong> of Radio Altimeters can be expected when operated near base stations – many of which are located near major airports –\u00a0until they are turned on it is hard to know…\u00a0<\/strong><\/p>\n

The FAA also suggested that while issues with RAs are the primary problem, it is unknown what else may be impacted<\/strong> so crew are going to have to be extra vigilant of their instruments, and of passengers potentially connecting to 5G networks while airborne because the impacts are just not known.<\/p>\n

What has the FAA done?<\/h4>\n

The FAA has issued two airworthiness directives<\/strong>, one for aircraft and one for helicopters, in an attempt to enable \u2018the expansion of 5G and aviation\u2019 <\/em>to \u2018safely co-exist\u2019.<\/em><\/p>\n

This is in addition to an earlier Special Airworthiness Information Bulletin<\/a> issued in November 2021 highlighting the Risk of Potential Adverse Effects on Radio Altimeters.<\/strong><\/p>\n

Let\u2019s take a look at the new directive.<\/h4>\n

The FAA determined that – \u201cat this time, no information has been presented that shows radio altimeters are not susceptible<\/strong> to interference caused by C-Band emissions\u201d<\/em>\u00a0and because they don’t know, they have to mitigate against the possibility that they will be.<\/p>\n

So, AD 2021-23-12<\/b><\/a>\u00a0requires\u00a0the \u201crevising of the limitations section of the exiting airplane\/aircraft flight manual (AFM) to incorporate limitations prohibiting certain operations requiring radio altimeter data when in presence of 5G C-Band interference as identified by NOTAMs.\u201d<\/em><\/p>\n

In other words, you’re going to need to amend your AFM<\/strong> so it takes into account the possible impact of 5G.<\/p>\n

The AFM revision will look something like this –<\/p>\n

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The AFM revision showing RA restrictions<\/p><\/div>\n

What’s the impact?<\/h4>\n

In short – possibly a lot, possibly nothing, and the only way to tell is to check NOTAMs.<\/strong>\u00a0Start checking them now, because operations using the new spectrum started December 5.<\/strong><\/p>\n

The key word in the revision is\u00a0‘interference’\u00a0<\/em><\/strong>because again, that won’t be entirely known until base stations are switched on and reports received. Which puts operators in a tough spot because those approaches that are prohibited (because of interference) are effectively all your precision approaches and means of landing in reduced weather conditions:<\/strong><\/p>\n