St Elmo's Fire
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Not exactly rare. And while it does occur sometimes when near storms, really all you need is some particles in the air rubbing up against each other creating electric fields. The times I have seen it were in clouds, not necessarily associated with turbulence and also not necessarily followed by a lightning strike.
Have just finished some study on lightning strikes and found some interesting stuff. Didn't know most strikes on airplanes are negative strikes but some (less than 5%) are positive strikes. The positive ones are the ones that can and often do real damage. Negative strikes leave pits and tiny holes. Positive ones can knock stuff off airplanes.
The thing that most associate with lightning is ignition of the fuel tanks and from what I could find, that is an extremely rare occurrence, especially in jets with the very high flash point of jet fuel. With avgas there is a slightly higher risk.
With St. Elmo's you can take your finger and walk some of the charge around on the outside of the window and yes, it does screw up your comm/nav sometimes.
Have just finished some study on lightning strikes and found some interesting stuff. Didn't know most strikes on airplanes are negative strikes but some (less than 5%) are positive strikes. The positive ones are the ones that can and often do real damage. Negative strikes leave pits and tiny holes. Positive ones can knock stuff off airplanes.
The thing that most associate with lightning is ignition of the fuel tanks and from what I could find, that is an extremely rare occurrence, especially in jets with the very high flash point of jet fuel. With avgas there is a slightly higher risk.
With St. Elmo's you can take your finger and walk some of the charge around on the outside of the window and yes, it does screw up your comm/nav sometimes.
From False Capture
Whilst you're investigating St. Elmo's Fire why don't you also have a look at 'plasma balls' which are seen following a lightning strike on an aircraft. They are usually about 12" in diameter and travel down the cabin from nose to tail at about waist height. Just like St. Elmo's Fire they are the result of a gas being turned into a plasma (ie. an ionized gas) by a high voltage.
I experienced this phenomena once during the early eighties in a 737-200 while climbing out of Malpensa with a load of Italian schoolchildren in the back. There were thunderstorms in the area when the lightening strike entered the cockpit near the F/O's windscreen wiper. The fireball passed through the flight deck door, travelled down the aisle, frightening the passengers and cabin crew far**less before exiting through the rear galley. We later found a static wick missing from the starboard elevator. Two things remain in my mind. The loudness of the bang, the brightness of the fireball and 130 normally unruly passengers who stayed strapped in their seats for the rest of the flight to Gatwick.
Whilst you're investigating St. Elmo's Fire why don't you also have a look at 'plasma balls' which are seen following a lightning strike on an aircraft. They are usually about 12" in diameter and travel down the cabin from nose to tail at about waist height. Just like St. Elmo's Fire they are the result of a gas being turned into a plasma (ie. an ionized gas) by a high voltage.
I experienced this phenomena once during the early eighties in a 737-200 while climbing out of Malpensa with a load of Italian schoolchildren in the back. There were thunderstorms in the area when the lightening strike entered the cockpit near the F/O's windscreen wiper. The fireball passed through the flight deck door, travelled down the aisle, frightening the passengers and cabin crew far**less before exiting through the rear galley. We later found a static wick missing from the starboard elevator. Two things remain in my mind. The loudness of the bang, the brightness of the fireball and 130 normally unruly passengers who stayed strapped in their seats for the rest of the flight to Gatwick.
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Plasma balls
We would love to investigate plasma balls as well. I hadn't realised that they were a 'frequent' appearance after a lightning strike (by 'frequent' I mean more than one person has encountered it!), but I've probably heard about 4 or 5 reports of the same phenomenon now. I guess it requires the same conditions as St Elmo's, but we should be ready with cameras to capture a potential plasma ball going down the aisle as well! Anyone have any description of how fast the plasma ball might move?
Thanks again to everyone who's responded so far. I have been following up all the leads you have given me, though not yet pinned down exactly where is the best location - or found myself someone mad enough to take us up there in a storm...
Thanks again to everyone who's responded so far. I have been following up all the leads you have given me, though not yet pinned down exactly where is the best location - or found myself someone mad enough to take us up there in a storm...
Alex
My example moved relatively slowly. After the initial bang of the lightning strike, it was possible to see it move the relatively short distance to the F/D door. If I remember correctly, the cabin crew said it was not "over in a flash", if took a couple of seconds to travel the length of the cabin. It also left behind that acrid smell of electricity. You will need an amazing amount of luck to film a plasma fireball. I only experienced it once (with around twenty lightning strikes) during a flying career of forty years.
BTW, the most spectacular St Elmos fire I have seen was flickering around the spinner and prop blades of the Bristol Britannia east of Bahrain.
My example moved relatively slowly. After the initial bang of the lightning strike, it was possible to see it move the relatively short distance to the F/D door. If I remember correctly, the cabin crew said it was not "over in a flash", if took a couple of seconds to travel the length of the cabin. It also left behind that acrid smell of electricity. You will need an amazing amount of luck to film a plasma fireball. I only experienced it once (with around twenty lightning strikes) during a flying career of forty years.
BTW, the most spectacular St Elmos fire I have seen was flickering around the spinner and prop blades of the Bristol Britannia east of Bahrain.
Last edited by brakedwell; 23rd Feb 2007 at 06:42.
St Elmos
We used to get St Elmos fire on the twin ADF Ae on the nose of the Hastings. That and the ADF unlocking and trying to find the nearest cu nim were usually the only signs that we were anywhere near trouble. No 'cloud and clonk ' in that venerable frame. Also had several strikes in the Herc. Worst was en route Kiev to Lyneham, big bang, flash and a slowish ball of lightning rolling down the cargo compt. Followed by a loud banging on the fuselage roof a la Tony Hancock. One of the Hf Ae had come adrift and frightened us to death. We diverted to Brno where the G/E removed it and we carried on to Lyneham. I believe the exit hole for the strike was up in the 'ducksbill but it seems a long time ago now so I could be wrong. And no the E290 had not given any indication of trouble.
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AlexF - here you go...
http://www.liveleak.com/view?i=24461f251c
http://www.liveleak.com/view?i=24461f251c
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I've seen St Elmo's numerous times on numerous types. Most visible at night (obviously).
IMHO, if you're struck by lightning as I have been a few times, you will have seen St Elmo's immediately beforehand. However, just because you see St Elmo's, you won't necessarily be struck.
IMHO, if you're struck by lightning as I have been a few times, you will have seen St Elmo's immediately beforehand. However, just because you see St Elmo's, you won't necessarily be struck.
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Alex
I've seen it many times whilst flying in one of HM pointy jets and have seen it most recently in an A321 on climbout from Birmingham. We were both trying to recognize star constellations when the St Elmo's fire started. We instinctively 'leapt' backwards and I quickly got out my digital camera. Unfortunately, although it was the most spectacular occurrence I'd ever seen, by the time I got the camera running, all I caught were the last couple of flashes. If you PM me with your email address I could send you the file if you're interested.
By the way, we weren't in cloud at the time and there were no storms nearby.
Better yet, I've just a quick search with Google and there's a very good image of St Elmo's Fire as it appears on aircraft windshields at:
http://en.wikipedia.org/wiki/St_Elmos_Fire
I've seen it many times whilst flying in one of HM pointy jets and have seen it most recently in an A321 on climbout from Birmingham. We were both trying to recognize star constellations when the St Elmo's fire started. We instinctively 'leapt' backwards and I quickly got out my digital camera. Unfortunately, although it was the most spectacular occurrence I'd ever seen, by the time I got the camera running, all I caught were the last couple of flashes. If you PM me with your email address I could send you the file if you're interested.
By the way, we weren't in cloud at the time and there were no storms nearby.
Better yet, I've just a quick search with Google and there's a very good image of St Elmo's Fire as it appears on aircraft windshields at:
http://en.wikipedia.org/wiki/St_Elmos_Fire
Last edited by meadowbank; 1st Mar 2007 at 13:07. Reason: Edited to insert link
