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Is it possible for navigational instruments to get affected by static electricity or electrical discharges like lightning? If so, how does this happen?

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  • $\begingroup$ What kind of instruments are you talking about? Complex computers like the ones of an Airbus? Or rather basic instruments like the ones in a GA aircraft? $\endgroup$ Jun 23 '15 at 14:38
  • $\begingroup$ @Madhav welcome back after a long long break... $\endgroup$
    – anshabhi
    Jun 23 '15 at 14:45
  • $\begingroup$ As a historical note, ADFs receiving NDB signals are typically no longer used for enroute navigation, but when they are, lightning makes it difficult since the ADF needle swings toward a lightning strike rather than staying pointed at the NDB station. $\endgroup$
    – Terry
    Jun 24 '15 at 3:00
  • $\begingroup$ What do you mean "rather basic"? Our GPS/NAV/COM units are pretty complex too. Mine is actually marketed as a Flight Management System, and can do everything the big boys can do. $\endgroup$
    – CrossRoads
    Oct 22 '19 at 15:40
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This will depend on the system, but the over all answer would be Yes at least to some extent. When talking about VOR/VORTAC/DME/NDB/GPS or any other nav system that relies on both a device in the plane as well as a device elsewhere we must consider how these devices talk. In this case we are talking about radio waves (em propagation), and lighting does produce an EM field so it has the capability to interfere.

That being said "interference" has both a technical term and a reality IMO. On paper, yes this may interfere with the signal but in reality lightning is fast and isolated so its momentary interference may not interfere with the operation of the device over a usable amount of time or may cause a momentary drop out.

Local INS (Inertial Navigation Systems) if you have it would remain generally unaffected.

There is another issue that presents itself if the lighting is very very close to the aircraft and will be more of an issue with composite aircraft. For what it's worth, if the whole skin of an airplane is conductive (as with metal skinned aircraft) it will act as a pretty solid Faraday cage. This will vary from plane to plane but is generally true. Thus if the lightning generates a strong enough EM pulse the interior of the plane will be protected from it. On a composite based plane you potentially expose yourself to flux related power surging. It should be noted that the critical electronics are protected from this kind of damage.

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ADF receivers just point to the strongest RF signal at the frequency that they are set to. I've seen them swing and point to a thunderstorm. I've even read of intentionally setting to a non-used frequency and then using the ADF receiver as a "poor-mans" Stormscope. Just don't follow that needle into a storm!

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Before , I answer this question, I would like to elaborate that navigation instruments can broadly be classified into three 1. Radio Instruments 2. Pressure Instruments 3. Gyro- Instruments Radio Instrument are only instruments effected by the static electricity. Radio instruments work on radio signals , which are electromagnetic in nature. Static electricity interacts with the electric components of the signals , hence static interference is there. However, VHF and above frequencies are not effected by the static electricity. Wick discharges , hanging at trailing edge of the wings , are being used to get rid of static electricity

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