Okay... my guess looks bad. This is metal-on-quartz sparking or static discharge? If the latter, is it continuous or does it pulse (a bad question, I guess, since, itf it pulses at a high enough freq, it'll look continuous anyway).
But will it do it with a composite rotor as on AH-1W?
And how do you account for it happening in high-humidity conditions? That would look to favor static discharge as opposed to sparking...
