is there any relations between STATIC DISCHARGE & LIGHTNING STRIKE?
 

few days ago in a class, an senior instructor told me there is no relation between STATIC DISCHARGE & LIGHTNING STRIKE, and static discharge(st. elmo's fire) is harmless. is this true? 'cause as far as i can understand, static discharge begins because aircraft can not let electric charges out, when electric charges in aircraft accumulate to a certain level, there will be a lightning strike. am i wrong?

Your instructor is correct.
Let me quote some advice from the Australian Bureau of Meteorology: "St. Elmo's Fire - as visible evidence of electrical discharge at a tolerably slow rate, this is not a problem, does not cause any form of damage, and in fact serves in a positive sense as a warning that the enviroment is electrified, and lightning may possibly occur."
If you do experience St. Elmo's Fire inflight, you should have the aircraft prepared for both lightning and turbulence. Cockpit lighting turned up, crew and passengers with seat belts fastened, ignition on, engine anti-icing on etc.

To a certain extent I agree with Erebus. I am not sure whether I read his reply as he intended it, so I would hesitate before disagreeing with him on any detail.

So perhaps I may paraphrase (or rephrase, or give my own paraphrasis :uhoh: )

St. Elmo's Fire is in itself totally harmless. It can be spectacular to watch. It is a sign of slow static discharge by the aircraft to atmosphere and therefore that the static wicks are working (fairly hard). The aicraft is accumulating static at a rate close to the rate at which it can shed it. This will not cause lightning strike.

It is, however, a portent of other problems. Provided the WXR is on, you should be able to see any storm cells in the vicinity and therefore avoid them. What is more difficult to see on radar, though, is volcanic ash or sandstorms, both of which can be accompanied by St. Elmo's Fire.

A good article in Sci-Am this month; goes into the nitty gritty somewhat.

What I didn't know was the extent to which cosmic forces play a part in the cascading electron build up. A good read, but focused on a particular aspect of the physics.

However, if you're flying tonight and there is some thermal instability in the offing, skip this and read Playboy. :oh:

... I noticed a pink glow, at first barely discernible, enveloping the windscreens.
"I think we are going to be struck by lightning!" I announced to the other two.
Glancing across at the two to whom I was speaking, it became patently obvious from their look in their eyes that their reaction was: 'Our Captain is cracking up'.
That old familiar pink glow was getting brighter and beginning to turn yellow. It would come any split second now.
"We are going to be struck!" I exclaimed in a voice rising several notes higher, and instinctively ducking my head. The other two pilots were now looking at me in unabashed amazement when an ear splitting crash rent the air.
Head down and still looking across at them, I now had a broad smile on my face. They were sitting bolt upright with nostrils twitching at the scorched smell still lingering on the air. There was absolutely no need to say, 'I told you' - their expressions said it all.


Behind the cockpit door, by Arthur Whitlock

I had exactly the same experience as that quoted by LEM. Watching the St Elmo's getting brighter and bigger, I called "Stand by for lightning strike!". A satisfactory 30 sec later there was a bang as we were hit. For some time afterwards I was treated with considerable suspicion as someone who could see into the future!

So, to answer the Eagle's original question, there is a relationship, but it is indirect.