Lightning Strikes
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June 8, 1999: NASA Science News
Learning how to diagnose bad flying weather-
Scientists discuss what they know about lightning's effects on Spacecraft and Aircraft.
Full story: http://science.nasa.gov/newhome/head...ssd08Jun99_htm
Learning how to diagnose bad flying weather-
Scientists discuss what they know about lightning's effects on Spacecraft and Aircraft.
Full story: http://science.nasa.gov/newhome/head...ssd08Jun99_htm
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Took a strike one night (C402C, solo, single pilot IFR S.E. Aust) thru the Stbd engine prop boss, engine stopped never to run again. It went out the top of the vertical stabiliser blew the placcy fairing off as I discovered later. Total elctrical failure did get most of the systems back. In and out of cloud, no moon, no TS activity apparent on the radar or forecast.
Major damage to pilots seat cushion with several large washer sized holes discovered later.
Fair thought I had died and gone to hell.
Major Flash instantaneous Boom followed by darkness and chaos whilst trying to work out what had happened and if in fact I was still alive. So much for Joe Cool pilot.
Took a whole bottle of Scotlands finest to stop the shakes, mind you that's what causes them nowadays
Hey Redders aren't the NW TS awesome we used to sit out the back with a slab on days off just watching them build 50 to 60K was not uncommon. On the ground by lunch or you were lunch for the TS.
Major damage to pilots seat cushion with several large washer sized holes discovered later.
Fair thought I had died and gone to hell.
Major Flash instantaneous Boom followed by darkness and chaos whilst trying to work out what had happened and if in fact I was still alive. So much for Joe Cool pilot.
Took a whole bottle of Scotlands finest to stop the shakes, mind you that's what causes them nowadays
Hey Redders aren't the NW TS awesome we used to sit out the back with a slab on days off just watching them build 50 to 60K was not uncommon. On the ground by lunch or you were lunch for the TS.
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Statistically, commercial aircraft average two lightning strikes per year per aircraft.
I count myself lucky, in that I have only been in two aircraft struck by lightning.
The first was a C-124 Globemaster, at 8000 ft. over the South American jungle, at night. I have no idea as to when we were hit, however there were lightning flashes and thunder close by for over an hour. On the lightning inspection at Recife, several holes were found in the top of the verical stabilizer and rudder. These were thought to be exit burns. No other damage was discovered.
The second time was on a DC-9. After departure, we were vectored around several cells. We saw lightning flashes and heard thunder close by. We didn't think we had been hit. However, at the gate one of the rampers came to the cockpit and informed us that the taxi lights were broken -- both of them. Closer inspection showed that lightning had burned a hole in the nose gear door, arced to the landing gear through the taxi light assembly. One light bulb was completely gone, the other had only the base and filiments dangling by the wires. That cost us a two hour delay waiting for parts and a mech. to install them.
Not very exciting, but that's the way I like it.
[This message has been edited by WINDY7C (edited 23 July 1999).]
I count myself lucky, in that I have only been in two aircraft struck by lightning.
The first was a C-124 Globemaster, at 8000 ft. over the South American jungle, at night. I have no idea as to when we were hit, however there were lightning flashes and thunder close by for over an hour. On the lightning inspection at Recife, several holes were found in the top of the verical stabilizer and rudder. These were thought to be exit burns. No other damage was discovered.
The second time was on a DC-9. After departure, we were vectored around several cells. We saw lightning flashes and heard thunder close by. We didn't think we had been hit. However, at the gate one of the rampers came to the cockpit and informed us that the taxi lights were broken -- both of them. Closer inspection showed that lightning had burned a hole in the nose gear door, arced to the landing gear through the taxi light assembly. One light bulb was completely gone, the other had only the base and filiments dangling by the wires. That cost us a two hour delay waiting for parts and a mech. to install them.
Not very exciting, but that's the way I like it.
[This message has been edited by WINDY7C (edited 23 July 1999).]
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Slasher: True the 737 seems to always get hit just below the sliding window .. BUT that's just the tip of the (damage) ice-berg.. for all those that think just because they have weather radar Airliners don't get hit by lightning often.. we had a 737-400 getting hit 2 times in a week grounding the a/C for more than a day each (well that was really bad luck).. both times the first look just showed burn marks below the sliding window but a closer look revealed several burned through holes in the lower fuselage just aft of the forward cargo door farme going further back towards the tail fin .. the lighning finaly went out of the airplane taking the tail fin static discharger aswell as a 2 x 2 inch big pice of the tail fin end cap. But that's just the easy to see things .. if you have a look at an airplanes upper fuselage section (crown area) during C or D checks you'll notice a lot of strike hits that just go unseen ...
Phil (DW6)
Phil (DW6)
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There are two distinct types of strike, namely, a full-blown lighting strike and, more commonly, a static discharge. Fortunately, most of us usually experience the latter, powerful as they may seem. Wise use of WX radar, and MK1 eyeball, avoids most of the former. To save space, I'll refer to them as LS and SD (sorry!).
Aircraft flying through charged cloud (St Elmo's etc) often trigger a SD even though the cloud itself is not producing a lightning storm. The damage is usually restricted to small holes or burn marks on some part of the airframe. This is akin to Slasher's "buggerall amps".
A real LS is millions of volts AND 30,000-200,000 amps and can register its mark on your beloved airplane in a significant way. Checkboard's examples of known lightning fatalities are not alone, as there are many more where, in flying into a fully-developed CB, the question remained as to whether the lightning or the turbulence broke the airframe first. That is why the WX radar has major significance in most company MELs.
Without wishing to tempt fate, I have not suffered a LS in the past 30 years, but I have had many SDs whilst making my best efforts to avoid either. I did, however, watch a Continental 747 take a direct hit, a few years ago, from my perch on the Surrey Downs, overlooking LGW.
There was an active TS/Cb lurking NE of the field and, looking out of my lounge window, I saw the 747 brushing the base of it. A bright bolt came out of the cloud and struck the nose. The aircraft was simultaneously "haloed" in light and a series of forks came off the wingtips and tail, continuing to ground. The aircraft landed back at LGW with serious damage to its nose and was on the ground there for days afterwards. Anyone out there remember this one?
It's the amps that do the damage and, I suspect, most of us only experience Slasher's amperage, thank heavens! There is an old book called "The Flight of Thunderbolts", by BFJ Schonland, FRS., (1950, OUP), which makes fascinating reading for those who are interested (No ISBN, I'm afraid). Although recent storm-chasers and meteorologists have made great inroads into why, when and where storms occur, the physics of lightning in this book remain valid.
There is even an interesting section concerning aviation in Ch3 which mentions tests carried out by NACA (pre-NASA), little if any of which seems dated.
(If anyone knows of an ISBN website, by the way, could you post it here? Thanks!)
Aircraft flying through charged cloud (St Elmo's etc) often trigger a SD even though the cloud itself is not producing a lightning storm. The damage is usually restricted to small holes or burn marks on some part of the airframe. This is akin to Slasher's "buggerall amps".
A real LS is millions of volts AND 30,000-200,000 amps and can register its mark on your beloved airplane in a significant way. Checkboard's examples of known lightning fatalities are not alone, as there are many more where, in flying into a fully-developed CB, the question remained as to whether the lightning or the turbulence broke the airframe first. That is why the WX radar has major significance in most company MELs.
Without wishing to tempt fate, I have not suffered a LS in the past 30 years, but I have had many SDs whilst making my best efforts to avoid either. I did, however, watch a Continental 747 take a direct hit, a few years ago, from my perch on the Surrey Downs, overlooking LGW.
There was an active TS/Cb lurking NE of the field and, looking out of my lounge window, I saw the 747 brushing the base of it. A bright bolt came out of the cloud and struck the nose. The aircraft was simultaneously "haloed" in light and a series of forks came off the wingtips and tail, continuing to ground. The aircraft landed back at LGW with serious damage to its nose and was on the ground there for days afterwards. Anyone out there remember this one?
It's the amps that do the damage and, I suspect, most of us only experience Slasher's amperage, thank heavens! There is an old book called "The Flight of Thunderbolts", by BFJ Schonland, FRS., (1950, OUP), which makes fascinating reading for those who are interested (No ISBN, I'm afraid). Although recent storm-chasers and meteorologists have made great inroads into why, when and where storms occur, the physics of lightning in this book remain valid.
There is even an interesting section concerning aviation in Ch3 which mentions tests carried out by NACA (pre-NASA), little if any of which seems dated.
(If anyone knows of an ISBN website, by the way, could you post it here? Thanks!)
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About 4 years ago,a Bristow 332 Super Puma helicopter got struck while cruising over the North Sea. The charge exited the helicopter at the tail rotor blade and caused one of the tip weights to detatch itself. The tail rotor vibration pulled the tail gearbox off of its mounting and the aircraft ditched successfully in quite heavy seas. Everybody got out ok. Eurocopter, the UK CAA and the company have done a lot of work on lightening strikes since to try to reduce the risk of another ditching.
I had a strike once on the North Sea in the same type of helicopter. Didn't know anything about it until the engineers discovered a hole the size of my fist in a main rotor blade. The main blades are composite with a metal leading edge. Just thought you'd like to know...
I had a strike once on the North Sea in the same type of helicopter. Didn't know anything about it until the engineers discovered a hole the size of my fist in a main rotor blade. The main blades are composite with a metal leading edge. Just thought you'd like to know...
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About 1 year ago, in an a300, I was flying out of Beruit heading to Larnaca. I was the PF, my wife was also sitting in the cockpit during the T/O. CBs were scattered around the Airfield. On passing 3000' we got hit by lighting, it struck us right underneath my sliding window with a loud bang. The first thing we did was to check engine parameters and the Magnetic compass, both were ok. The rest of the flight was uneventfull (My wife thinks otherwise!)
About 2 months later, the exact same thing happened except this time it was at 4000'. What struck me as odd (pardon the pun) was that the lighting struck at the excact same place, just under my sliding window?
Any insight to this phenomenon?
About 2 months later, the exact same thing happened except this time it was at 4000'. What struck me as odd (pardon the pun) was that the lighting struck at the excact same place, just under my sliding window?
Any insight to this phenomenon?
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My only lightning strike in 15 years of flying also hit us just beneath the sliding window. It left 5 burnt spots about 2cm in diameter along the paintwork. See photo at: http://www.chris.brady.ukgateway.net/lightning.htm
S & L
S & L
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Long ago, I was taught that the route of lightning was normally wingtip to wingtip or nose to tail. My first three strikes mystified me when I could find the entry point but not the exit. Turned out that it went nose to wingtip on all three (2 on Cessna 400 series and third on Bac1-11).
Have had many flying around the tropics in 747s of all types without major damage - a few welded rivets, holes in GRP panels etc.
Grounding is now so good that there is often little to tell. Certainly in the modern glass jets, a compass check is a bit superfluous since, with the excption of the standby compass, all magnetic displays are generated by computer from the true track data from the IRS.
Biggest gotcha can be if the radar stops working - could have blown your radome off. Happened to a VC10 out of east coast USA many years ago and he barely made Shannondue extra fuel burn. Check those fuel flows!
Have had many flying around the tropics in 747s of all types without major damage - a few welded rivets, holes in GRP panels etc.
Grounding is now so good that there is often little to tell. Certainly in the modern glass jets, a compass check is a bit superfluous since, with the excption of the standby compass, all magnetic displays are generated by computer from the true track data from the IRS.
Biggest gotcha can be if the radar stops working - could have blown your radome off. Happened to a VC10 out of east coast USA many years ago and he barely made Shannondue extra fuel burn. Check those fuel flows!
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Some pilots above seem to think that they have only been hit once in a career. Actually those are only the times that they knew about. It also says somewhere above that the average strike rate is once every 3000 flight hours. I don't know where this figure comes from but it is clearly incorrect. In several years experience of routine inspections at "A" check intervals (usually about 500 to 600 hours) I can vouch that you NEVER find an aircraft without lightning strike evidence. Typically there is at least one static discharger blown off with evidence of flash/heat on the remains of the base plate. Pointy bits of the aircraft especially the fin cap and the tips of antennae have melted bits which we blend out and touch up. Most radomes have pin prick holes in them that need sealing and touch up. Then there are the "stich marks" along the fuselage sides that no-one but engineers notice. This is a long series of pin point strike marks in a long line. Of course, only us "sparkies" go peering really close at the aircraft looking for this evidence but next time you do a walkround, try looking more closely at what look like pin prick black marks. Go on -- frighten yourselves 
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Info noted. Plse report further.
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Info noted. Plse report further.
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Sorry to go off at a tangent but the following concerns severe wx:
Years ago in my 737-200 days we were within 100 miles of TOD when our single wx radar failed. It was daylight, the forecast & actual for our destination were not indicating any adverse wx, the vis was good and there was a solid layer of cloud below us stretching across the horizon with a smooth top at approx. 10.000'.
We contacted the radar controller at our destination and also spoke to aircraft that had just got airborne climbing towards us and enquired if there was any wx painting on anyone's radar. All responses were negative so we continued cautiously to our planned destination.
During the descent we entered the cloud layer at approx. 10.000' and due to the requirement for engine anti ice and 55%N1 (so long ago, is that the correct figure?) speedbrake was required to maintain an appropriate rate of descent. Shortly after entering the cloud we hit what we later discovered to be a rapidly developing Cb that had been totally obscured by the surrounding cloud. With full speebrake extended and an IAS of 280 kts our ROD became a ROC of 1500ft/min and the noise of the hail hitting the ac was so intense that we could not hear one another across the flight deck. I kept thinking that the eyebrow windows would give in and even though the encounter only lasted approx. 30 secs it was one of the most frightening experiences of my flying career.
Upon reaching the stand the engineer's jaw dropped in amazement. Inspection of the a/c revealed that 2/3 of the nosecone had been punctured, the top and bottom anti-collision light structures were missing, the wing root landing light housings were destroyed, all the leading edges were dimpled and the spoilers looked as though someone had taken a hammer to them.
Having reported the encounter to ATC, within minutes of landing we were informed that the met office had earlier issued a hail warning and dispatched an airman (doing his national service, it was a joint civil/military airfield) with the information to pass on to ATC, but he was distracted en-route and never passed it on!!
Years ago in my 737-200 days we were within 100 miles of TOD when our single wx radar failed. It was daylight, the forecast & actual for our destination were not indicating any adverse wx, the vis was good and there was a solid layer of cloud below us stretching across the horizon with a smooth top at approx. 10.000'.
We contacted the radar controller at our destination and also spoke to aircraft that had just got airborne climbing towards us and enquired if there was any wx painting on anyone's radar. All responses were negative so we continued cautiously to our planned destination.
During the descent we entered the cloud layer at approx. 10.000' and due to the requirement for engine anti ice and 55%N1 (so long ago, is that the correct figure?) speedbrake was required to maintain an appropriate rate of descent. Shortly after entering the cloud we hit what we later discovered to be a rapidly developing Cb that had been totally obscured by the surrounding cloud. With full speebrake extended and an IAS of 280 kts our ROD became a ROC of 1500ft/min and the noise of the hail hitting the ac was so intense that we could not hear one another across the flight deck. I kept thinking that the eyebrow windows would give in and even though the encounter only lasted approx. 30 secs it was one of the most frightening experiences of my flying career.
Upon reaching the stand the engineer's jaw dropped in amazement. Inspection of the a/c revealed that 2/3 of the nosecone had been punctured, the top and bottom anti-collision light structures were missing, the wing root landing light housings were destroyed, all the leading edges were dimpled and the spoilers looked as though someone had taken a hammer to them.
Having reported the encounter to ATC, within minutes of landing we were informed that the met office had earlier issued a hail warning and dispatched an airman (doing his national service, it was a joint civil/military airfield) with the information to pass on to ATC, but he was distracted en-route and never passed it on!!
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Dr Syn, Must have been quite a sight, the Conti getting in the way of a cloud/ground strike.
Must take issue about the two types of strike however, as a lightning strike is nothing other than a large static discharge between opposingly charged objects.
As perceived by the public these would be clouds and Earth or whatever were attached to/standing on it. An aircraft may gain a relative charge quicker than the wicks can discharge it under certain circumstances.
I have had four full blown strikes over 35yrs in Europe, depite taking pains to avoid obvious cells. The bang and the flash were probably the worst thing about them. Two were preceded by the most intense Elmo's I have ever seen with a huge cone of "fire" extending from the aircraft nose.
In the RAF, a compass "swing" used to be mandatory after such an encounter, as they reckoned the magnetism of the structure would be changed.
Must take issue about the two types of strike however, as a lightning strike is nothing other than a large static discharge between opposingly charged objects.
As perceived by the public these would be clouds and Earth or whatever were attached to/standing on it. An aircraft may gain a relative charge quicker than the wicks can discharge it under certain circumstances.
I have had four full blown strikes over 35yrs in Europe, depite taking pains to avoid obvious cells. The bang and the flash were probably the worst thing about them. Two were preceded by the most intense Elmo's I have ever seen with a huge cone of "fire" extending from the aircraft nose.
In the RAF, a compass "swing" used to be mandatory after such an encounter, as they reckoned the magnetism of the structure would be changed.
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billovitch,
RAF Compass swings were much more accurately done than civilian swings. Military aircraft must be able to get about without reference to ground based aids. In a war situation your enemy is not likely to leave the VORs operating or provide ATC to help you find your way
Before INS most RAF aircraft carried a navigator and used doppler updated Ground Position Indicator Systems to track the aircraft's position. The Doppler needed really accurate compass data and it was not unusual to spend a whole day swinging the compasses to get them accurate within a quarter of a degree. So, a lightning strike would be quite capable of putting the compasses out of calibration. When I got rid of my Blue Serge Suit, I was a bit taken aback by the casual civilian approach to compass swings, but IRS has sent the things to the museum now. Standby compasses are mostly only accurate to the nearest 3 or 4 degrees these days.
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RAF Compass swings were much more accurately done than civilian swings. Military aircraft must be able to get about without reference to ground based aids. In a war situation your enemy is not likely to leave the VORs operating or provide ATC to help you find your way
Before INS most RAF aircraft carried a navigator and used doppler updated Ground Position Indicator Systems to track the aircraft's position. The Doppler needed really accurate compass data and it was not unusual to spend a whole day swinging the compasses to get them accurate within a quarter of a degree. So, a lightning strike would be quite capable of putting the compasses out of calibration. When I got rid of my Blue Serge Suit, I was a bit taken aback by the casual civilian approach to compass swings, but IRS has sent the things to the museum now. Standby compasses are mostly only accurate to the nearest 3 or 4 degrees these days.
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Through difficulties to the cinema
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I had a ride on the jumpseat on a flight last year and we were struck by lightning about 10nm from touchdown. About 2 weeks later I tried to use a digitally truned portable vhf receiver which had been in my hand baggage. It had been working earlier in the day of the lightning strike, but I was unable to tune any station afterwards. Would that be attributable to the lightning strike or just coincidence?
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Yet another Tech Log thread that has suddenly been revived from the past. Someone must have been trawling!
The point I think I was trying to make, billovitch, was that there is a difference in intensity between a full-blown 30-200ka "bolt" that is self-initiating, and a static discharge that is simply triggered by the presence of one's aircraft. The former has been known to blow radomes or panels off planes, while the latter leaves small scorches or pin-holes.
I am not sure if any scientists have ever actually defined the boundary between the two, and would be the first to admit that it is probably the last thing on one's mind when there is a blinding flash and a deafening bang! However, I seem to remember that, in general, where there is otherwise no electric storm in progress it would normally be considered a static discharge.
Meanwhile, if you can obtain it, Schonland's book is a fascinating read.
The point I think I was trying to make, billovitch, was that there is a difference in intensity between a full-blown 30-200ka "bolt" that is self-initiating, and a static discharge that is simply triggered by the presence of one's aircraft. The former has been known to blow radomes or panels off planes, while the latter leaves small scorches or pin-holes.
I am not sure if any scientists have ever actually defined the boundary between the two, and would be the first to admit that it is probably the last thing on one's mind when there is a blinding flash and a deafening bang! However, I seem to remember that, in general, where there is otherwise no electric storm in progress it would normally be considered a static discharge.
Meanwhile, if you can obtain it, Schonland's book is a fascinating read.
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Spotter--
It's quite possible that the lightning strike broke your radio even without any direct contact, and it's more likely if you had the antenna plugged in at the time. Do the digital bits still work -- can you still enter frequencies and move around the band? If so, the problem's most likely to be in the circuitry that's directly connected to the antenna, and that might not be so expensive to fix. If nothing seems to be working, it may not be worth getting it repaired. Some of the modern scanning radios are nightmares to work on...
R
It's quite possible that the lightning strike broke your radio even without any direct contact, and it's more likely if you had the antenna plugged in at the time. Do the digital bits still work -- can you still enter frequencies and move around the band? If so, the problem's most likely to be in the circuitry that's directly connected to the antenna, and that might not be so expensive to fix. If nothing seems to be working, it may not be worth getting it repaired. Some of the modern scanning radios are nightmares to work on...
R
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Self Loading Freight - Yes the antenna was connected at the time. The digital stuff does still work, just can't get anything other than static no matter what frequency it's tuned to. (not even any different pattern of static no matter what freq. which i thought was strange.)
Anyway I'm not too bothered as it was getting on a bit & I've bought a replacement now. I was just curious really as it stopped working so abruptly. It took me about 6 months actually before I connected the two events.
Anyway I'm not too bothered as it was getting on a bit & I've bought a replacement now. I was just curious really as it stopped working so abruptly. It took me about 6 months actually before I connected the two events.
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Blacksheep mentioned pin-prick holes in the radome. Interesting follow on to this observation. We had an on-going problem with a B737-200 which regularly flew in the West and Central Pacific area. Lots of moisture. As anyone knows who flies in that area, Cb and lightning abound. We had Bendix RDR-1E radar - if I remember correctly. Problem was that we could only get returns within 80 miles during cruise. Guam, a island around 60 miles long, could easily be picked up at 180 miles on our other 737's - but not this particular 737.
Cruising in cloud, Cb returns would loom up at 80 miles, first as tiny returns, then full blown serious stuff as we got within 30 miles. Made long range assessment of typhoon clouds a bit late. Below around 8000 ft on descent or climb, returns were normal.
Despite snagging the radar numerous times, techs in Hong Kong (our servicing base)could not fault the radar.
In desperation, I took a series of photos of the radar picture of Guam from 180 miles in the 737 with normal radar returns, and again with the 737 with the dodgy radar (ie 80 miles if we were lucky). I sent these to Bendix in USA with a request for ideas.
They said that in all probability, the radome was letting in water through pin-point holes in the radome. The water would eventually freeze inside the honeycomb and form an ice barrier. The radar beam then becomes attenuated and very little energy gets through. Hence poor range at high altitudes. In warmer temperatures, the ice melts and the radar works normally. Hence, ground checked - serviceable at Hong Kong.
Bendix said bake the radome to dry out the trapped moisture, then repair the radome.
No problem after that.
Cruising in cloud, Cb returns would loom up at 80 miles, first as tiny returns, then full blown serious stuff as we got within 30 miles. Made long range assessment of typhoon clouds a bit late. Below around 8000 ft on descent or climb, returns were normal.
Despite snagging the radar numerous times, techs in Hong Kong (our servicing base)could not fault the radar.
In desperation, I took a series of photos of the radar picture of Guam from 180 miles in the 737 with normal radar returns, and again with the 737 with the dodgy radar (ie 80 miles if we were lucky). I sent these to Bendix in USA with a request for ideas.
They said that in all probability, the radome was letting in water through pin-point holes in the radome. The water would eventually freeze inside the honeycomb and form an ice barrier. The radar beam then becomes attenuated and very little energy gets through. Hence poor range at high altitudes. In warmer temperatures, the ice melts and the radar works normally. Hence, ground checked - serviceable at Hong Kong.
Bendix said bake the radome to dry out the trapped moisture, then repair the radome.
No problem after that.