Static Discharge Wicks

Radar Contact

Radar Contact

Pattern Altitude
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Kevin
For a while now I have noticed at times my radio's get a bit of static in them when receiving ATC. Many times when I'm further from the transmitter but not so far this should be happening. Also at times when I'm close to the transmitter depending on the direction I'm traveling. Additionally, I've had receiving issues with localizer and glide slopes during ILS'es. I took it to an avionics shop many months ago and they said they found a corroded connector, cleaned and tested and all is well. Considering I prefer GPS approaches to ILS a lot of time went by before I checked it but I was still having reception issues.

I noticed several of my static wicks were in bad shape and started researching about it. While the majority of the static issues that effect nav/com's seem to happen while flying through visible moisture, I came across an article explaining that it can also cause these issues in aircraft that cruise above 150 kts in clear air.

So before spending more money at an avionics shop chasing this issue I had my A&P replace the wicks during my annual that just finished yesterday. To my surprise, it completely fixed my bit of static and I was able to receive the localizer and glide-slope normally. I've only had the chance to test it after flying around for 2 days but so far so good.

Just thought I would share my experience in the event anyone else may be having a similar issue.
 
And then one day you'll be flying along all happy....static slowly creeps into reception, some clouds around but high bases and not particularly dark...it's getting tough to talk to ATC because of the static....then it happens, a flash of lightning and the static goes away for awhile...time to be somewhere else...
 
At work, on older 121 commercial jets, we've seen a lot of p-static issues with composite panels that weren't properly painted or grounded. In the case of painting, some were supposed to have a conductive metallic layer of paint to conduct the charge to structure. It was missing because the repair vendor saved a few bucks. Other times it was bonding strips and jumpers. It's usually panels that stick out in the air stream, leading edges, radomes etc. We brought in a guru to show us how to use our Dayton Granger Static Tester, I had seen used before, but didn't recognize what they were doing. If charge builds up and is not conducted away, eventually the potential builds until is arcs, making noise all across the VHF band. I've seen videos of the electric arc jumping from panel to panel found during a sweep with the tester. I don't know enough about static discharge wicks, but in correspondence with the OEMs they do make a difference. Somehow their design lowers the resistance to charge dissapation.
 
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I often wonder how really affective they are on small aircraft. Often they are installed over painted surfaces and then never inspected later in service with proper equipment, flight control bonding cables missing etc, how good could they be?

Jets --They are on an inspection cycle, regularly checked for proper electrical bonding. Wicks themselves are tested to see if they are good. There are specific maintenance procedure for R&R of the bases and specify paint-free properly prepared, use conductive adhesive part # _________ etc. All the flight controls are bonded to the main aircraft.
 
bnt83 said:
I often wonder how really affective they are on small aircraft. Often they are installed over painted surfaces and then never inspected later in service with proper equipment, flight control bonding cables missing etc, how good could they be?

Jets --They are on an inspection cycle, regularly checked for proper electrical bonding. Wicks themselves are tested to see if they are good. There are specific maintenance procedure for R&R of the bases and specify paint-free properly prepared, use conductive adhesive part # _________ etc. All the flight controls are bonded to the main aircraft.
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From my own experience and research:

They probably aren't very useful unless your small aircraft cruises above 150kts in clear air. In snow/rain they may be useful at slower speeds.

In order for them to be useful they do need to be in good shape, they can't be installed over painted surfaces and the flight control bonding cables must be in place and properly bonded. There is an instrument to test them (not sure if my A&P did) but my testing came in the fact that after proper replacement (new correct wicks re-installed on paint free surfaces) of them all my radio static and loc/gs problems that were always present are now gone.

Maybe different air-frames and configuration (i.e. de-ice boots installed) can be more prone to static issues? Maybe different avionics installations as well? I for sure don't know enough about all that, just happy to correct my issue relatively cheaply. :)
 
It seems the tool for checking the attach bonding is called a Meggar
 
Gary Austin said:
It seems the tool for checking the attach bonding is called a Meggar
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We typically use meggers to find wiring that may have marginal insulation. Most bonding checks I've seen are done with a meter capable of reading very low resistances. Years ago, I remember checking the bonding of fuel valves with a Wheatstone bridge, because an old Simpson meter didn't read resistances under 1 OHM very good.
 
Clark1961 said:
And then one day you'll be flying along all happy....static slowly creeps into reception, some clouds around but high bases and not particularly dark...it's getting tough to talk to ATC because of the static....then it happens, a flash of lightning and the static goes away for awhile...time to be somewhere else...
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Ha. And nowadays a lesser known benefit of ADF. You’d know you were headed for some seriously00 crappy weather 100 miles away when the ADF ident started sounding like a fireworks display and the needle started wandering around.

I’ve definitely been in aircraft that didn’t do 150 that the static socks and associated hardware were shot and listened to hours of static buildups on the airframe and the little zap when it finally found a way to equalize.

Have an acquaintance who swears the equalization was happening through his old David Clarks one time in someone else’s aircraft and after about two hours of it he was really really mad. LOL.
 
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