Lightning strike to a plane at the gate.

[Phillbo]

From a buddy in ATC:


You'll need to watch it several times ; it's only about 11 seconds.

Watch closely at the tail of the plane. (looking for a lightning strike) Then replay it and watch the front landing gear.
Then wonder why we don't refuel airplanes if there is lightning in the area.

Three key things/areas to watch
1. first watch the tail of the aircraft as the bolt hits the vertical stab, do not blink, it happens that fast.
2. Next, watch the nose of the aircraft where ground crew is walking up to, and under, the nose of the plane.
3. Then, look just to your left of the nose gear. That brown square on the ground is a metal plate imbedded in the concrete, with a small manhole cover. The strike exits onto the metal plate, and sends the manhole cover flying through the air toward the tug on the far left.



http://www.youtube.com/watch?v=ilK6n64ypes

[Truckman]

All I can say is, "Dayum!"......Ben

[SBA]

As I recall , military aircraft refueling stations in Vietnam had 'lightening rods' sticking up in the air higher than the top tail of any aircraft. These were usually just fabricated out of 're-bar' steel rods with the end buried about 6-ft in the ground.

[chew 'n' spit]

What Ben said............

[Truckman]

The memory of 40 years ago is a tad hazy, but I think I recall using ground straps from the airframe to a ground rod in the pad anytime one of our fighters was parked on the flightline...

The scariest part of every ordnance upload was having to test continuity of the release cartridges used to open the hooks holding the bombs in place...This meant running low-voltage electricity with an ohmeter through the live explosive cartridges to insure continuity...Ever once in a while we'd hear about an oversensitive cartridge going off and opening the hooks on live ordnance...Not very often, but it did happen......Ben

[SBA]

I've experienced two inflight lightning strikes, both in a C-47/DC-3 aircraft. Just a big 'flash' ... the magnetic compass whirled round and round ... radio buzzed ... and that was it. Noticed a little burn spot discoloration on the wing tip later. Of course, the Vietnamese co-pilot had to change his skivies later.

http://www.scientificamerican.com/ar...s-when-lightni

[Mike]

Getting back to the original post, I wonder what it did to the avionics and the other electrical systems on the aircraft? It would be interesting to know.

[Phillbo]

Probably nothing ...

[Mike]

Really?

At work, lightning hit a Pine tree that was about six feet away from an overhead power line that fed parking lot lights. Apparently, the lightning jumped from the Pine tree to the power line and fried the hell out of everything attached. The county's electricians spent about three days fixing all the lights.

[chew 'n' spit]

In my limited, very limited understanding of aircraft they have discharge capacitors located all over the aircraft to divert lightening strikes from essential electronic devices.

[SBA]

I've heard numerous tales of aircraft encountering 'fire balls' inflight in thunderstorms. This guy had one roll down the aircraft aisle ...

R. C. JennisonJennison, of the Electronics Laboratory at the University of Kent, described his own observation of ball lightning:

I was seated near the front of the passenger cabin of an all-metal airliner (Eastern Airlines Flight EA 539) on a late night flight from New York to Washington. The aircraft encountered an electrical storm during which it was enveloped in a sudden bright and loud electrical discharge (0005 h EST, March 19, 1963). Some seconds after this a glowing sphere a little more than 20 cm in diameter emerged from the pilot's cabin and passed down the aisle of the aircraft approximately 50 cm from me, maintaining the same height and course for the whole distance over which it could be observed. [18]

[SBA]

In my limited, very limited understanding of aircraft they have discharge capacitors located all over the aircraft to divert lightening strikes from essential electronic devices.

Yep ... you see these ''dissipators" on most commercial and military aircraft ... I had one on each wingtip fuel tank and on both surfaces of the V-tail of my Beech Bonanza; however, I viewed them mostly as 'static electricity' dissipators - anytime you move about any conductive object through the air, you generate electricity , same as when you walk on the carpet and get a spark when you touch the metal door knob.

Question

"How is a plane protected from Lightning strikes?

Answer

Since the outer skin of most airplanes is primarily aluminum, which is a very good conductor of electricity; the secret to safe lightning hits is to allow the current to flow through the skin from the point of impact to some other point without interruption or diversion to the interior of the aircraft.
Estimates show that each commercial airliner averages one lighting hit per year but the last crash that was attributed to lightning was in 1967 when the fuel tank exploded, causing the plane to crash. Generally, the first contact with lightning is at an extremity...the nose or a wingtip. As the plane continues to fly through the areas of opposite charges, the lightning transits through the aircraft skin and exits through another extremity point, frequently the tail (as shown by Gauss's Law).

Another related problem with lightning is the effect it can have on computers and flight instruments. Shielding and surge suppressors insure that electrical transients do not threaten the on board avionics and the miles of electrical wiring found in modern aircraft. All components that are vital to the safe operation of commercial aircraft must be certified to meet the stringent regulations of the FAA for planes flying into the United States.

Answered by: Rich Uranis, B.S., University of Michigan, Ann Arbor


Aircraft, and by that I mean the body of the aircraft and not the occupants inside, are protected from lightning strikes by two things. The first and most important of these is the brains of the pilot and the weathermen who predict where violent storms are likely to be. The second is through a small unsung device called the "static wick".

Most aircraft do not fly into lightning storms, or fly through storms or areas where lightning is likely to be present. What we see as lightning is really a massive flood of electrons seeking equilibrium, either from cloud-cloud or from cloud-ground. In both cases, huge amounts of electric charge build up at the edges of the cloud. The electricity finds it's way from one place to the other via what's called a "step leader".

The sheer power of the cloud will start to attract electrons from the ground. These electrons will gather on anything that gathers charge (like a fence) or sticks up in the air (like a person), or that does both (like a telephone pole). That electric charge will start to work it's way through the air, ionizing it, until the leader working it's way down, and the leader trying to get up finally meet. When they do - there's lightning. An aircraft flying between the highly charged portions of a cloud will act as a conduit for step leaders, being able to produce one in each direction. If either of them meets a leader coming the other way... ZAP.

The way an aircraft tries to dissipate these step leaders is through the use of something called a "static wick". A static wick is a piece of metal connected electrically to the frame of the aircraft, with one or two spikes or needles on the end. It is housed in a fiberglass rod to insulate it from the airplane. Because the spikes concentrate the electric charge around them, and they are connected to the airframe, they allow the airplane to dissipate any static electricity it may build up out into the air. Also - if lightning DOES strike the plane, the chances are that the electricity will go through the dissipator and not through the airplane. You can see pictures of these dissipators on the 737 webpage below.

So, when discussing how an airplane is protected from a lightning strike, the best safety feature is the pilot who checks the weather before he flies and makes smart decisions about where to fly. If the plane is forced to fly through a storm, the static wicks on the wing's trailing edges should help keep the plane safe.

Answered by: Frank DiBonaventuro, B.S., Air Force Officer, Physics grad, The Citadel

[Phillbo]

elmo

http://www.youtube.com/watch?v=ufKMRSkFrds

[chew 'n' spit]

elmo

http://www.youtube.com/watch?v=ufKMRSkFrds

Holy shirts...........