5-G Interference and “ELA”

How to keep the Cessna 170 flying and airworthy.

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GAHorn
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5-G Interference and “ELA”

Post by GAHorn »

One of the Aviation Periodicals I receive monthly is “Avionics News”. It’s primarily directed at Avionics Shops and most articles address issues too “high tech” for most Cessna 170 owners …. EXCEPT those who also fly more sophisticated aircraft professionally…. as it’s directed mostly at turbine operators and some smaller commercial operations.

Anyway… the June 2021 issue has two articles which, in summary, might be of interest to our group.

If you are excited about 5G connectivity you might be interested to know that it is being discovered to interfere with some legacy avionics when operating near high-RF-output 5G transmitters. It can be especially troublesome to radar altimeters, (admittedly not particularly common to C-170 aircraft) and also to some audio-amplifiers.
So…. if you’re experiencing interference with your legacy audio amps and/or nav/com radios…. you might research to see if those episodes of interference occur at predictable locations… and report it to the FCC and FAA…. so that the problem can be addressed. Although I doubt many 170s are operating Cat II or Cat III approaches…. it might display itself with some communication system issues.

In another June 2021 article the mag reminds shops and operators of the requirement to re-address Electrical Load Analysis (ELA) of their aircraft anytime equipment is installed or removed or replaced. Advisory Circular AC 25-10 provides guidance for the installation of miscellaneous, non-required electrical equipment that calls for an ELA to confirm that the continuous electrical load does not exceed 80% of the generated electrical capacity. FARs require an accurate accounting of electrical loads versus generating capacity and anytime equipment is removed or installed the ELA should be revisited.

I recently replaced some older Incandescent lamps with L.E.D. equivalents and so it was tempting to simply think to myself….”Well…it’s LESS than BEFORE, so there’s no need to re-Analyze the Electrical Load. But while that may be “safe”….that is a “lazy” way to do things and it does not comply with the rule. It also does not re-identify the “base line” of my aircraft and if I add additional equipment in the future then I’ll not have an accurate starting-point to determine the ELA of my aircraft.

Hint: I replaced the incandescent GE4509 Land/Taxi lights on my airplane with L.E.D. equivalents. While that reduced their electrical load by 20 Amps…. they are NOT part of the “continuous” electrical load. Land/Taxi lamps are “intermittent” electrical loads and are NOT included in the “continuous” ELA. So…. although they give me a warm and fuzzy feeling…. and although they reduce the demands upon my generated load compared to the incandescents they replaced… they do not benefit or improve my ELA numbers.

When did you last perform an ELA on yours?

Just FYI. :wink:
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons. ;)
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