Lightning strike. What happens?

[VMC-on-top]

If you are unfortunate enough (or stupid enough) to be caught in severe weather and are struck by lightning, what happens? Presumably you avionics / radio all fry? Do you stand a risk of death if touching the metal part on the internal side of the door? Would the aircraft still fly?

Not that I plan to test it of course, just out of interest!

[PompeyPaul]

I'm not an expert, but I did my degree in electronics. I believe the aircraft would act as a Faraday cage because it isn't earthed. That being the case no current would flow as you would have equal potential around the aircraft. Even if you touched the metal part of the aircraft the "current" would route around the metal airframe and down to earth. That is where the greatest resistance would be, where the voltage was dropped and where the power would be dissipated, hence you'd see the white hot heating of the air molecules and the classic "lightning" strike.

That said, as my physics A level teacher told me "really, nobody totally understands lightning yet, we've got some ideas but it's not all completely known" so I am more than ready to be corrected.

[tom775257]

http://www.caa.co.uk/docs/33/AIL0014.PDF

The above link contains some background information. I seem to remember reading a report about a glider that was destroyed by a strike, however the glider was non-conductive. I know a chap who was hit in a 172 I think which destroyed the wing tip but nothing else. Larger aircraft seem to show little damage after a strike, perhaps the odd rivet burnt or an aerial or cover blown off, often I fly aircraft with small amounts of lightning damage awaiting rectification.

[Whopity]

A big bang and a flash, a temperature change, a strange smell and some kit may not work and crew members wondering what the hell was that.

[IO540]

A certified all-metal plane should keep going OK.

There is a mandatory engine shock load inspection because the current often travels via the prop and can fry some bearings/gears etc.

Composite planes can vary in what happens. The IFR certified ones are supposed to contain grounding mesh within the composite, which is all bonded together.

[ross_M]

Do you feel it in the plane when it hits you? Especially in the big planes. And for the commercial pilots out there; how often do you get a hit anecdotally?

Is a lightning hit something you'd report to the ATC (like chop)?

[UAV689]

I believe there was a glider about ten years ago, composite that got zapped by one of gods volts and the thing vapourised. IIRC if was because of water vapour in the airframe that boiled, expanding and causing airframe to explode.

The pax on that flight had his first glider flight at parachute jump that day

[mad_jock]

in my limited experence of 3 strikes a whole heap of swearing.

All three were different one we thought we were hit by an RPG, one we hardly noticed it. And the other all the avionics went tits up and we had a magnitised something or other which meant all the nav kit apart from the GPS was tits up. That one something welded in the wing as well which we "broke" to get things working properly again. It took 5 months inthe hanger to get that airframe legal again.

[thing]

I was in a 767 that was struck by lightning shortly after take off from Gatwick. Big bang and flash . We dumped fuel and landed, not sure if that's an SOP or whether it was something that had gone tits up on that particular a/c. They put me in a very nice hotel for the night (I was flying non cattle for once so really got my money's worth) .

We took off in the same a/c the next day, which caused a few worried frowns and at about the point when we should have been halfway across the pond I was looking out of the window at the green fields of Ireland. I knew we had some kind of problem but was keeping my own counsel when the pilot came on with the most classic PA announcement I've ever heard:-

'Ladies and gentlemen I have the worst possible news.......' and before he got the rest of the sentence out a great unified scream came from the back of the plane before he continued with 'we have to return again as our radio system has malfunctioned'. Cue relieved moan from back of a/c.

I had another night in a splendid hotel, Manchester this time as for some reason he diverted there and if I remember correctly I had some if not all of the fare refunded.

Lightning strikes are fine by me.

[Pace]

i have posted this before. I had a lightning strike in a Seneca five about 8 years ago.

FL120 passing close to Dublin and trying to get through a line of hefty CBs.
There was a blinding flash and I saw the lightning bolt hit the wing some 2 to 3 feet from where I was sitting in the left seat of the Seneca.

The Bolt hit between the engine and fusealage on the wing leading edge.
All that was noticeable was the radios going into a mass of crackle.

I asked for vectors onto the ILS at Dublin and all the way down the glideslope the aircraft appeared to be setting off lightning flashes.

The storm was so bad that all the aircraft were lined up on the taxiways waiting for the storm to move and Dublin had stopped all refueling.

Brilliant for teeth whitening and hair volumising but not much else.
Worst was the windshear which knocked the autopilot out and dropped us several hundred feet :)

Some couple of hours later when the storm had passed we took off again for shannon with the aircraft no worse for wear,

Pace

[cats_five]

There was indeed a glider zapped by lightning:

http://www.aaib.gov.uk/cms_resources.cfm?file=/dft_avsafety_pdf_500699.pdf

The AAIB went to town on the investigation and refered to other investigations that involved lighting. The report has a huge amount of information about lighting in it, it's worth a read.

All the metal linkages to control the ailerons were severely damaged, though AFAIK the fus was pretty much intact until impact.

The AAIB state (paraphrased) that the strike was probably 8-9 times stronger than the current certification level for protected aircraft. There was a resulting safety recomendation:


Recommendation No 99-49 It is recommended that the CAA should request serious consideration, during its participation in the current international review of aircraft lightning certification standards, of the fact that energy levels from positive polarity discharges have been shown to greatly exceed those specified in Advisory Circular AC 20-53A, with the associated implications for the certificated lightning protection assurance of existing and future aircraft designs, particularly those which utilise significant amounts of composite material in their primary and control structures.


Unfortunately this PDF doesn't have the images in - I have found them before, they are out there somewhere on the Internet.

Clearly this has implications for all the composite microlights out there - and unlike the K21, the occupants AFAIK don't normally wear parachutes.

[jamie2004]

Had this on a Global Express on way into Biggin, Horrible wx about all over the south east, was struck as intercepting on the ILS, knocked the radios out for a few seconds along with a small hole on the nosecone and one at the back of the aircraft, apart from that, not much of an event!

[cats_five]

I found a web page by the P2:

TinyURL.com - shorten that long URL into a tiny URL (http://preview.tinyurl.com/63ln85v)

This is the unadulterated URL - it would need joining into one to be useable:
http://2540561622994096994-a-1802744773732722657-s-sites.googlegroups.com/site/thebig40reachfortheskiesagain/Home/999gli
dingpdf1.pdf?attachauth=ANoY7crOdZSYOMt0kMSf2wVRLg0PbKPdoXk5
I2_6iPhvXEXjQp1RxmBQ_BspvnBp1Z3U_lBYfNnUZbsSMT_hLSFbsFPjeJW9
tj8fOWGurCCzjrGSlvbCAaAgZNbJO9SNyxoCLO_0zFQOaNjjHnN8NIYAqg08
UTijlxDID9dDnF5hYYXfklG-qo4kM6EwN0n5JAZlckEMyHoVNh-8xY67I0H4
CB6K_sqn2vXSlEaPcpfP7k_BecNXbwo%3D&attredirects=0

The page has not only the AAIB photos taken when the remains of the glider were laid it out at Farnborough, but a number of photos of the wreckage at the impact location, and of the P2 returning 10 years later to fly at the same site with the same instructor in another K21. He took the fleece he was wearing in the fated flight and there is a photo showing the singing on that as well.

[ShyTorque]

As far as the possible effects of a lightning strike to the individual: always think of this:

BZwuTo7zKM8

[peter36]

The glider that was hit by lighting was from Dunstable. I remember going to a presentation of what happened by a guy from the the AAIB. Thinks that stick in my mind are

The current went down and around the control rods in the wings and fuselage and was estimated at 500000 amps and considerably more powerful than most strikes and a rare event.

It vaporised the ball linkages and the explosion from the sudden expansion of air inside the wings and fuselage blew the glider to bits leaving the cockpit (minus canopy), tail section and the wing tips. Everything else disappeared.

Both pilots got out although the instructor was concussed and survived. He still flies at Dunstable.

The remaining tubular control rods were crushed into C sections and twisted by the huge magnetic forces.

There was no warning and despite the large cloud there was no evidence of any electrical activity. The AAIB guy thought that if it had hit a passenger plane then it may have been powerful enough to bring it down.

[Graeme Cooper]

That was me, I was the passenger in the glider that was destroyed by lightning. Read my story and see the BBC TV of the reconstruction:- The BIG 40 reach for the skies again (http://sites.google.com/site/thebig40reachfortheskiesagain/)

[chrisN]

Graeme, thanks so much for that. What a superb record of the events and aftermath, and well done with the charity fundraising.

Chris N.

[cwatters]

Thanks for the great write up Graeme.

With all that damage to metalwork of the glider its a wonder you had any fillings left in your teeth :-)

[Pilot DAR]

Amazing, Graeme....