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Old 4th Apr 2006, 14:40   #1 (permalink)
 
Join Date: Jul 2005
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Lightning strikes

Poor weather in Toronto yesterday and quite afew aircraft were getting struck by lightning. Poor BA and Air France got multiples!

I have never been on an airline when it has been struck. I know that all modern airliners are equipped to deal with it but from a cockpit perspective I would be interested to know what happens when you are struck?. Lights flashing, instruments flicker etc etc.

How accurate is the weather radar in cockpits nowadays?

Just curious
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Old 4th Apr 2006, 15:37   #2 (permalink)
 
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....in my limited experience of (3) lightning strikes, all you really notice is a VERY LOUD BANG !!!!

Cheers
mcdhu
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Old 4th Apr 2006, 16:51   #3 (permalink)
 
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Lightning Strikes

Was in the second spin in the OCK hold at FL090 one morning last October. The conditions werenít the best, as we were holding in towering CU with heavy rain and continuous moderate turbulence. It wasnít very comfortable. As we started the turn back to OCK from the south end of the hold the F/O read my mind and stated, quite prophetically, that the conditions were about right for a lightning strike.

No sooner were the words out of his mouth when there was a bright flash on the left side and the immediate clap of very loud thunder, which drew my immediate attention to the screens & instruments. Not even a flicker! Everything continued normally.

It didnít surprise us too much as we were both expecting it. I think it would have been quite spectacular had it been at night.

Inspection on the ground revealed a bit of scorching at the strike point on the left engine intake cowl, with the exit point at the aft end of the engine. Otherwise, no damage and no adverse instrument effect.

As far as the radar goes, it is very accurate for rain. But in a small space, like in a hold and the immediate approach area, you tend to use the short ranges which are going to show the rain to be everywhere, so it isn't going to tell you what you don't already know. Also, at the short ranges, like 20 miles and less, the radar tends to be overly sensitive and in a lot of cases makes things look worse than they really are. It's best used on the medium to longer ranges for weather avoidance.
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Old 4th Apr 2006, 16:52   #4 (permalink)
Couldonlyaffordafiver
 
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I got struck out of YUL at night a few months ago. Huge bang and all the screens went to full brightness. Otherwise ok, until we got to the Atlantic and found none of the HF radios worked!! CPDLC and Satcom got us across and we found a large scorch mark just below the flight deck on arrival.
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Old 4th Apr 2006, 17:23   #5 (permalink)
 
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All the above is correct. The problem is that lightning also can happen outside of a thunderstorm cloud or propagate from inside to the outside.

The results of a lightning strike can be manifold, from nothing happening to holes in the structure to instrument and other components failure. The complete instrument failure can happen, but it is rare, and according to my observation rather happened on the last generation electro-mechanical generation than on the latest gadgedery.

I had one a multiple lightning strike on a turboprop and after the flight it showed that the lightning entered the cell, exited and reentered again, thus producing three holes in the upper left front fuselage. Those holes can be from tiny to one or two centimeters in diameter (that's up to an inch). But surprisingly the cabin pressure isn't really an issue, because the bleed system can provide more pressure than air is leaking.

Interesting lightning strike had been observed when lightning entered the cockpit and/or cabin and generated some light shows.

Dani
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Old 4th Apr 2006, 18:26   #6 (permalink)
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I was in a Canadair CL44 turbo-prop freighter enroute from Lagos to Kano in the 1970's when we were struck one night.

St Elmo's fire turned the windscreen laminate into a mass of purple veins,
like a leaf, and the tips of the propellers looked like Catherine Wheels!

When we arrived at Kano and did a walk round there was a small hole
in the skin near the base of the fin. Apart from that the aircraft was
fully serviceable, and it did not affect the integrity of the pressure hull.

The turbulence was interesting though!!
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Old 4th Apr 2006, 18:50   #7 (permalink)
 
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Don't look now, but the ERJ that I fly is very susceptible to lightning strikes. The company for which I work has had numerous lightning strikes.
On the ERJ, instruments are often affected, holes are left in the nose,tail and sometimes the wing.
Several of our aircraft, after being struck by lightning, had constant static in the radios. On further inspection, it was found that the static wicks were burned to a veritable crisp.
The worst scenario, however, is one in which the elevator cables weld to the frame of the aircraft. We have had two aircraft do just that.
Rumor has it, however, that each of our aircraft, just prior to being struck, were in the following configuration:
1. Down low and slowed down for turbulence.
2. Radios began to "crackle" and "hiss" (all ERJ pilots know what I am talking about).
3. The smell of ozone came, then the "big bang."
The loud bang was so loud in one aircraft that the flight attendant, who was sitting in her jumpseat at the time, had an ear drum rupture.
So much for lightning strikes being benign.
Somebody help me get on with CX....
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Old 4th Apr 2006, 19:10   #8 (permalink)
Couldonlyaffordafiver
 
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Forgot to say, we lost about half a dozen static wicks...
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Old 4th Apr 2006, 19:49   #9 (permalink)
 
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Man thats hurts

Last year going into BKK on a dark night with to much traffic to go around the red wall of death so through we went, we had vertical lighting all around then one big flash (luv the smell of ozone) a big flicker and my symbol gen fell over then suddenly it wasnt fun any more, got through and landed ok and on looking found we had being hit in the engine cowl put a nice big hole in scary stuff, I think a common place for 737's
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Old 4th Apr 2006, 21:55   #10 (permalink)
 
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Been hit a few times - no big deal, just a bright flash and a bang (one was pretty loud, but had a couple that were just a dull 'thud'.

That said, I once saw the wreckage of a glider that was hit - it peeled open like a banana and the alloy aileron pushrods were just lumps that had been completely melted ! (luckily the 2 crew had parachutes and escaped with minor injuries and brown underpants !!!).

Last edited by Greenfinch; 4th Apr 2006 at 22:13.
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Old 5th Apr 2006, 07:33   #11 (permalink)
 
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http://www.pprune.org/forums/showthr...ight=Lightning
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Old 5th Apr 2006, 09:01   #12 (permalink)
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From a passenger perspective, I was in cattle class on a KLM 747 combi which got hit about 10 minutes before landing at AMS. There was an intense purple light in the cabin, a slight bang, the lights flickered and it was over (for us) although for some reason which I cannot explain, I got the feeling of being near a lot of energy. The Captain announced that there had been a lightning strike and not to worry

(I love the video above btw)
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Old 5th Apr 2006, 09:09   #13 (permalink)
 
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I once got struck in a Fiat car at 8,000 feet over the Central Massif!

Well actually, I was sitting in the car that was in the back of a Hastings when that took the strike. I went back up on the flight deck to find one chap who had his helmet off sitting there with his hair standing on end, a smell of sulphur and the compasses spinning round.

Fortunately the trailing aerial had been wound in so there was not too much damage to the signallers kit (or the siggy) and we had one VHF set still working. Paris and London gave us compass less guidance and we continued to a landing at Lyneham.

The aircraft was bonded but not as well as they are today.

One more amusing fact. In those days the ops manual stated that when freighting it was a good idea to fly into the odd Cu-nim to give the pilots practice at turbulence flying!
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Old 5th Apr 2006, 09:52   #14 (permalink)
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At 17000', 747 descending into BDA in heavy cloud, a stream of not brilliant lighning appeared coming through the cloud dead ahead streaming straight to the aeroplane. It must have lasted about 6 seconds or more. We had that funny atmosphere you get- our hair was standing on end because we were really scared- it looked at if it was heading straight between each of our knees. Ended with a very big flash and bang. I simultaneously felt something like a flick on my watch, which was new and rather expensive, but undamaged. That was one of the unusual strikes. Lots of flashes and bangs and holes made, but the scary stories are the ones about ball lightning appearing in the cabin and wandering about for many seconds. Still nobody knows anything about them. A prize for the first guy with the guts to stick a finger in one!
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Old 5th Apr 2006, 09:54   #15 (permalink)
 
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Watched a great doco on Discovery channel about sprite lightning. Google it or check this out. http://www.newscientist.com/channel/earth/dn8733.html.

They think designers will have to rethink how much energy will have to be dissipated through bonding...

They are attributing it to a number of previously unexplained hull losses. One of them a Pan Am B707!

Interesting stuff!

Anyone seen ball lightning cruise down the cabin? Or is that the aviation yeti equvalent?

(Holding inside towering CU? Seriously? )
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Old 5th Apr 2006, 13:37   #16 (permalink)
 
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I remember a 747 taking off from Heathrow that got struck. The crew saw some fluctuations in the engines and a bang. Everything seemed normal. Landing in Toronto the lead noticed something and advised the captian.

There was a 2 foot dent in the nose from where they were struck.

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Old 5th Apr 2006, 13:39   #17 (permalink)
 
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Exclamation

Lightning & ball lightning are very complex phenomena see link for some interesting information.

http://www.amasci.com/weird/unusual/bl.html

Regards
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Old 5th Apr 2006, 15:29   #18 (permalink)
 
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Metal a/c seem to do well with lightning. But what about composites? AAIB report into a Super Puma ditching -- lightning strike caused a composite tail-rotor blade to fail -- suggested that lightning protection standards were set way too low because the failure occurred at an unexpectedly high charge, four or five times higher than the max envisaged in the standard. Then and now, there haven't been enough lightning encounters with planes with a high proportion of composites to see this work out in real life. The current standards may be good enough for metal, but possibly not for composites. Interesting question for A380 and B787.
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Old 5th Apr 2006, 16:05   #19 (permalink)
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Elroy, I knew a steward who swore to me this story was true. He and a stewardess were sitting in the rear vestibule seats of a VC10. They're by the door right back between the engine intakes, so very noisy. Night, seat belt signs on, turbulence, facing rear, trying to hold a conversation. Around the bend next to his shoulder a ball of lightning had come down the cabin, gently around the bend and floated gently past them at shoulder height, heading towards door, moving very slowly. It then passed through the door and disappeared. Very funny atmosphere, hair on end (it would be!), stewardess hysterical, unable to swallow. Several other similar incidents known over the years in BA.
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Old 5th Apr 2006, 16:15   #20 (permalink)
 
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I heard a similar story on the BA285 B747-200 going LHR-LAX back in late 90s.
I watched it take off and saw it get struck by lightening somewhere Slough direction. Pax in question said the flash entered the cabin forward and exited rear. I didnt see that bit.
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