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EMI and ESD on helicopters

  1. Jul 11, 2007 #1

    What kind of problems ESD can cause to a helicopter? Blades are usually made from a carbonfibre and they can cause electrostatic charge into a helicopter structure. Is there any method to prevent that to happen?
    If that charging occurs, what happens when heli is landing, will it discharge itself in to a ground with a spark, or is it prevented somehow?

    What about charging differencies between different parts in a structure, lets say potential differencies. Helicopter blades are charghing themselves by static charge or some other parts in a helicopter, and its bodyshell is not, or charged less than other parts causing a potential differency between two parts. Is there a discharge happening time after time, or is this prevented by connecting different parts with a galvanic connection, wire or something like that?

    How this charge/discharge can affect into a onboard equipments? radio interferency, radar etc.
    Same sort of things might happen in a fixed wing plane too?

  2. jcsd
  3. Jul 12, 2007 #2


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    In aircraft you generally take great care to ensure that all the surface panels are electrically connected together forming a conducting cage.
    This prevents arcing between panels but also reduces the effects on any electical systems inside the aircraft.
    The atmospheric static built up on helicopters is a big problem, the ussually ground with either a metal strip on the undercarrigae or just rely on condution through the landing gear.

    It is a major danger in rescue helicopters where you have to be very careful to let a grounding strap touch the deck first before grabbing hold of the basket/stretcher.
  4. Jul 12, 2007 #3


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    I have never seen a helicopter discharge to the ground when landing or taking off. For aircraft like a Chinook, we had the benefits of a landing gear with tires so you were well insulated. There are small trailing wires (wicks) to alleviate build up in surfaces:
  5. Jul 12, 2007 #4

    i have seen some pictures where a helicopter has a discharging "wire" hanging from a bottom of its shell. Those pictures were taken in a helicopter landing area on a floating oil pumping station somewhere. Those discharging wires or plates are best solution as you can control the discharge with a series of resistors and it would prevent charges to discharge rapidly with a spark.

    I wonder why chinook helis dont discharge, or charge itself ?!?! If the heli charges itself it would probably be tens of thousands of volts, and it will discharge it even that there are rubber tires. If there is a potential differency, electricity will try to balance it no matter what ways, pilots steppin out from a heli, air discharge, langing gears, antennas, rubber tires and so on..
  6. Jul 13, 2007 #5


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    An oil platform is very different than solid ground.

    Chinooks DEFINITELY charge their rotors. However, like I mentioned, they do have some trailing wicks on the landing gear tucked in between the tires. If they do discharge on landing, it definitely is not large enough to see with the naked eye. I have seen, plenty of times, what happens when someone trying to hook up an external load on the ground and does not follow proper grounding procedures (http://www.globalsecurity.org/military/library/policy/army/fm/3-21-38/image470.jpg and http://www.globalsecurity.org/military/library/policy/army/fm/3-21-38/image471.jpg). The static discharge is enough to knock you on your butt. It hurts...a lot.

    We also had a hand held device called a shepherd's hook inside the aircraft. If we had to hook up an external load ourselves, we would use the shepherd's hook to grab the clevis to the sling through the hell hole. The hook was grounded to the structure of the aircraft. I assume that the entire fuselage acts like a large Faraday cage.
    Last edited: Jul 13, 2007
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