Aircraft Static Wicks - Static wicks are available with and without FAA and PMA approval and with various methods of construction. Dayton-Granger has PMA approval for a variety of discharge wicks for use on piston and jet aircraft. It also provides dischargers to OEMs.
Dayton-Granger's Javier Pacheco told us the company continues to advance its wick design, offering the Null Field discharger product, the Mircopoint discharger, the Carbonpoint discharger and a line of composite dischargers. The company also has a history of making high-quality aircraft antennas, plus lightning diversion strips.
Aircraft Static Wicks
As Avidyne put it: “Static buildup is a very real issue that cannot be mitigated at the equipment level. If the aircraft OEM intended static wicks to be installed, it had a reason for it, and if it didn't, it's still probably a good idea."
Are New Avionics More Immune?
As we flew along, p-static began to build in the headphones. I had that happen a time or two before, and it always cleared itself within a few minutes. This time it didn't. It got so intense that I could not hear the controller or anyone on the frequency.
In addition, the needles for both VORs began to oscillate randomly. A quick check resulted in hearing only static, no identifiers, on both radios. Most of the aircraft skin is bonded (connected) to the static discharge wicks with the exception of the windshields.
When we fly through high altitude ice crystals (cirrus clouds), heavy rain, or snow, the static discharge wicks don't dissipate the precipitation static that builds up on the windshields. The precipitation static eventually discharges on its own, providing a fascinating web-like display a few inches in front of us.
Anytime an aircraft flies, the friction of the air over the aircraft's skin causes the aircraft to build up static electricity. Discharge of the electricity can generate radio frequency interference (RFI) or static noise level. RFI can become serious enough to interfere with comm and nav radios to the point that reception becomes impossible.
What Would Happen Without Static Wicks?
Any particulate matter in the air, be it rain, snow, dust, sand or even volcanic ash, will cause more RFI to be generated as the material sticks to the aircraft and any protrusions, especially antennas, which is why they have an anti-
static coating. On your next flight, while you sit back, relax and enjoy reading SkyMall, there is a good chance your flight crew is enjoying their own, shocking light show. Pilots see static discharges dancing on our windshields fairly often.
As a passenger, you might be surprised or even concerned at the display. It can be very impressive, but it's completely harmless. Take a closer look at one of the coolest light shows that pilots experience on the flight deck...
Yes and no. We asked Garmin engineers about the effects of RFI on its retrofit and OEM avionics, including its most modern integrated suites for jets. One said that some modern systems are impervious to the effect (including GPS receivers) because GPS operates at such a high frequency.
What Happens If A Static Wick Falls Off?
However, navs, comms and audio systems operate at lower frequencies and are much more susceptible to static interference if the aircraft has worn or missing static wicks. As one engineer put it, "The importance of static wicks is about the same for a 50-year-old airplane with old avionics as it is for a brand-new one with an ultra modern glass cockpit."
Friction generated as an aircraft moves through the air can cause a buildup of static electricity. The wick, which resembles a wire, transfers that electricity back into the atmosphere to prevent it from interfering with navigation and communication radios.
In the unlikely event your trainer should get struck by lightning in flight, the static wick would work to dissipate the energy from that strike. There are normally around 15-20 static wicks on all commercial aircraft.
This is a significantly higher number than required, ensuring that in the case of damage, there is always a sufficient number to perform their task correctly. If it looked similar to the windshield static discharge pictures, than it was likely static discharge off the wings.
Keep Your Eyes Open For St Elmo’s Fire
Since you mention you were near thunderstorms, it might have been actual St. Elmo's Fire. I'd love to see a photo if you took one! In addition to radio static, you may experience a corona discharge when flying in precipitation.
Corona discharge involves a static charge so great that excess electrons start to ionize air molecules and form a visible corona around sharp objects on the airplane—the end of the prop, antennas or wing tips, for example.
The effect is known as St. Elmo's fire. A corona discharge, taken to its extreme, occurs when a spacecraft enters the atmosphere and ionizes the surrounding air, turning it into plasma and wiping out communications until the spacecraft slows down.
Yesterday as we were beginning our descent into Atlanta on a stormy night we saw what was depicted on Star Trek Next Gen when they are going at low warp speed. It was amazing. This was out the passenger window first row of seats on a 737. Anyone know what that is called?
Why Does A Plane Need Spikes On The Wings?
We were flying through Wisconsin from Minneapolis to Fort Wayne International back in September on a stormy summer evening through a very energetic thunderstorm with lots of lightning. I saw blue discharges like your pictures in the cockpit but they were smaller and were dancing back and forth on the wing.
Can you tell me what I might have witnessed? You've seen or heard static discharges around your house. In the winter, when you take a blanket out of the dryer, you can hear the static electricity snap and crackle.
If you turn off the lights and give the blanket a shake, harmless sparks can be seen as the excess static discharges. This is the same stuff we see on our windshields. Without static wicks — sometimes referred to as static discharges — the aircraft would gradually attain an increasing static electric charge as it passes through the air.
When flying through air with precipitation, such as ice or rain particles, this static charge can increase even more rapidly through a process known as triboelectric charging. Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician.
Wick It Away
Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.
Toll Free: 877-477-7823 Customer Service: 800-861-3192 Fax: 800-329-3020 As an aircraft flies through the sky, air and precipitation rub against the aircraft's skin causing a buildup of static electricity. The same thing happens when you rub a balloon on your hair.
When this electrical charge is strong enough, it can cause static on aircraft radios, interfering with communications. In typical conditions, the charge is continuously dissipated by small, pointed static discharge wicks mounted to the trailing edges of the wings and tail.
No matter the manufacturer, prices can range from $40 to as high as $85 or more for a wick suitable for a single or twin, and far more for jets. In general, most wicks for singles and light twins measure roughly 7 inches long and weigh .50 ounces each.
P-Stat Lesson Worse In Snow
Still, all of this effort has little effect on in-band noise sources, particularly in VHF. As Avidyne explained, as static charges build, move and collapse on the airframe, very wide-band RF energy is released; some amount of this energy will fall in-band for the VHF and other RF receivers.
The in-band component of the static noise is picked up by the antenna and amplified in the receiver as if it were the intended signal. Look at a static wick and you'll see a cord-like structure riveted directly to the skin of the trailing edge to make metal contact.
It may be wider where it connects to the airplane than at the end. Static wicks are bonded to the metal structure of the airframe. Because they are constantly transmitting electrons into the atmosphere, they eventually wear out—or at least the tips do.
Once that happens, RFI can develop on the airplane. If a static wick falls off, it's not a huge deal. As they are deliberately slender, and attached to the extremities of the aircraft, it's actually fairly common for them to become loose and fall off during flight.
Progress At Cirrus
Unfortunately, as a passenger, you probably won't see static discharges. I've never seen or heard of them happening on side windows. If you are flying on a stormy night, however, you might catch a glimpse of St.
Elmo's Fire on a wingtip similar to the photo above. If you see it, be sure to take a photo. It's a rare phenomenon and I'd love to see another picture of it! This charge cannot build up forever, and once the charge is large enough — based on a range of factors — it will look to discharge itself back to the surrounding atmosphere.
The charge will look for the easiest route. This is usually the thinnest part of the aircraft, such as the wingtips and tailplane. The resulting discharge of energy can result in a loud bang, heating, and even visible sparks.
They are unobtrusive for the most part, and sometimes they are overlooked on a preflight inspection. But static wicks—the small wires protruding from the trailing edge of an airplane's wing or empennage—serve an important function in the air.
Rarely, this can mean that the aircraft might even begin a flight without all the static wicks. Commercial aircraft can fly with some static dischargers missing for a set number of flights before they are required to be replaced.
Although I'm an avid fan of Star Trek – Next Generation, I don't know what you are describing. If you can provide a picture of the actual occurrence or a picture of what "Low warp speed" looks like, I might be able to figure out what you were seeing.
On the plane, St. Elmo's Fire appears as a bluish glow or flame emanating from an aircraft wingtip or nose. The phenomenon is rare on aircraft; most pilots have probably not seen true St. Elmo's Fire.
St. Elmo's can appear in heavily charged air in the vicinity of a thunderstorm and is harmless to aircraft. Turning on the landing light revealed that we were flying in moderate to heavy snow. I knew snow was worse than rain for generating p-static, but I'd never encountered anything like this.
I knew it was snowing in Grand Rapids and forecast to continue, so I started considering turning back to Cadillac where it should just be decent VFR with a high overcast. At that point I recalled something I'd learned when encountering St.
Elmo's fire and a remark made by an old freight dog. If you ride long enough through snow, fog and desert dust, you'll likely hear the audio signatures of static built up on the airframe. It can be severe enough to shut down a comm and nav receiver.
The troubleshooting chase can be as frustrating for the techs as it is for pilots because everything will likely work perfectly on the ground. Static discharge wicks should be the first accessories to consider, especially when committing to a new avionics installation.
But antennas could be the culprit, too. They are designed to be more attractive to static energy, than any of the other aircraft extremities such as antenna, wingtips, or flight controls. As the plane moves through the air, the wicks help to discharge any static electricity that has built up from the friction of the plane moving through the air.
Owners may struggle with getting the correct replacement, especially when sourcing them through mail-order supply houses. Aero-Mach's Jon Snider told us choosing the correct replacement wick should be easy because it's usually governed by the original type certificate of the aircraft, and replacement options are prescribed by the aircraft repair manuals.
St. Elmo's fire is a form of plasma that can occasionally be seen emanating from roof peaks, towers, spires, and other pointed objects in the vicinity of thunderstorms. The phenomenon is often seen prior to a lightning strike.
If you see it, get indoors! So, there you have it — the mystery of the static wicks solved! Now you know just what those metal rods are and why they're on plane wings. Next time you fly, take a look out the window and see if you can spot them attached to the back (trailing edge) of the wing!
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