Why your bags are delayed in a thunder storm

[ktcanuck]

Lightning Strike - Ground Ops

An AeroRepublica Embraer 190 hit by lightning in Medellin, Colombia at the gate. You'll need to watch it several times to see all of the action; It’s only about 10 seconds duration. Three key things/areas to watch. First watch the tail of the aircraft as the lightning bolt hits the vertical stabilizer, do not blink, it happens that fast. Next, watch the nose of the aircraft where ground crew walk up to and under the nose of the airplane, then quickly retreat. 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 an access cover in it. The lightning strike exits the airplane onto the metal plate, which sends the access cover flying through the air toward the tug on the far left.

[Beefitarian]

The lightning strike exits the airplane onto the metal plate, which sends the access cover flying through the air toward the tug on the far left.

That's crazy scary. Just before it happened, the guy that runs furthest away was right where the arc exited the plane to the ground.

[MIQ]

I remember when I was working the ramp for Lufthansa in Germany. When there were thunderstorms around and above the airport we were not allowed to continue ground handling. Had to disconnect all the equipment and especially were not allowed to use the headsets at all for ground-to-cockpit/cockpit-to-ground communication. Even when the thunderstorm was further away from the aerodrome we were supposed to perform the engine start up by hand signals only. Now I know why. The ground crew got really lucky there that no one was in contact with the aircraft and no equipment was connected.

Now I wonder, what would happen if the ground power unit was connected to the aircraft? Is there any kind of protection circuit breaker installed to prevent any damage or so? As far as I know these GPUs are not 'grounded'.

[Oor Wullie]

I'm not sure if this is the case for all airports, but, I believe there is a blue light called "Thor" that tower lights up when TS are in a certain range of airport. Ground crews vacate apron and seek shelter.

I guess these lucky lads didn't have that.

[ettw]

What is that thing that goes flying, landing near the bag tug to the left of the nose?

ETTW

[oldtimer]

I think the loading bridges must be protected in some way. I was on a Westjet flight that landed in Calgary just before a TS. We were informed by the flight crew that they were not allowed to park because the groundcrew took shelter, as required. But the crew also mentioned that the airplane at the next gate got there before the alert was sounded so they were able to disembark passengers because there was no outside ground crew required. Once informed, everyone just sat back and relaxed except for one idiot who wanted a smoke.

[Tommyr]

I'm not sure if this is the case for all airports, but, I believe there is a blue light called "Thor" that tower lights up when TS are in a certain range of airport. Ground crews vacate apron and seek shelter.

I guess these lucky lads didn't have that.

YVR has that system, blue lights all around the airport come on and every one is supposed to stop what they are doing and head inside.

[FlyGy]

What is that thing that goes flying, landing near the bag tug to the left of the nose?

ETTW

The access cover for the metal panel on the ground.

[Rudy]

So ground crew can move quickly.

[albertdesalvo]

That's a great video. I was sitting dockside in my boat during a storm a couple of years ago, and a sailboat about fifty feet away was struck. It looked *exactly* the same as this video. I was told later that all the electronics on the boat were toasted. People think you will see a brilliant white sheet of light or something, but really all you see is a spark and it's over. Just like in this video.

Would be interesting to know how the electronics in the plane made out. Sailboats have a plate built into the hull that's supposed to transmit the pulse into the water, and in spite of that everything in my neighbour's boat was fried. But a plane is a Faraday cage, and we saw the exit of the charge, so who knows?

Anyway, I have seen a lightning strike from fifty feet, and this video is dead accurate.

[Nark]

I had a good look through the manual for the E190. The only thing I can think of are numerous blown CB's, both thermal and electronic. It doesn't state ground protections in the case of lightning strikes.

It looks like the discharge came from where the RAT is located.

Here is the schematic of the AC system under GPU power. Someone who knows how to read greek care to answer MIQ's question?

[HeadingAltitudeSpeed]

I'm not sure if this is the case for all airports, but, I believe there is a blue light called "Thor" that tower lights up when TS are in a certain range of airport. Ground crews vacate apron and seek shelter.

I guess these lucky lads didn't have that.

The major Canadian fields have it. Thorguard works on a predicability of a lightning strike within a specific distance of the field. It has a few different levels of alert. When the Red alert is active (sounds like the blue lights) no ground crew activity on the apron is permitted. I have seen it active for a 5 hour stretch. Arrival can land but not get to the gate. Creates major traffic jams on the airport manoeuvring areas.

I have heard that some ground crews elect to ignore the warning but I am not sure of specific company protocols at each airport.

[co-joe]

That's a great video. ...People think you will see a brilliant white sheet of light or something, but really all you see is a spark and it's over. Just like in this video....

I think it may depend on the amount of current in the strike. When I was a kid, my parents and I were watching the stanley cup finals on tv in the living room when lightening struck the poplar tree directly across the street from our house. I can tell you with certainty that there was an enormous flash of white light that literally blinded us all for a second. When we could see again, the tree was split down the middle like a banana that had been peeled in all different directions. The noise and shock wave were so powerful the the whole house shook, and anything plugged in including our TV was fried.

[mdscientist61]

When lightning strikes a tree, the electrical current flows down the trunk. All the moisture inside the tree trunk and under the bark starts to boil with the heat, and when it turns to steam then the tree trunk bursts open and the bark gets jettisoned. One loose analogy would be a package of micro-wavable popcorn heating up.

In the video, the lightning struck the tail which was the pointiest part of the airplane closest to the cloud (even though the cloud might have been 1000 feet up).

Not totally clear fom the video, but it looks like the electrical current exited down through the nose landing gear strut, possibly out the metal hub of the wheel, which looks like the part of the airplane that has any metal closest to the metal-covered manhole in the ground.

If that manhole in the ground was lined with metal, or had a metal ladder leading down, then that would have been the path of least resistance for the flow of electrical current. As the electicity flowed down the manhole, it would have heated any water sitting in there, which turned to steam so quickly that it blew off the manhole cover like a steam-powered potato gun.

When lightning strikes a power pole, it can make a significant surge in the voltage of the power line. Then all your appliances get an over-voltage stress. Sort of like plugging your 120V television into a 220V socket. Even if the lightning strikes the ground or a tree a short distance from your house, without striking a power line, it can still cause electrical over-stress by creating a local surge in the potential of the ground near the strike. In this case the over-voltage stress would be between the ground connection of your equipment and the two connections to the AC lines.

[albertdesalvo]

Interesting! If you were watching hockey on TV, it would have been nighttime, which may account for the flash. When I saw the sailboat struck, it was about noon, so who knows how it would have looked at night. I happened to be looking directly at the boat when it was hit, and I saw a big spark come off the top of the mast and some chunks of stuff come fluttering down, pretty much the same as seen in the posted video. I remember thinking, "Holy shit, that's only one dock away!" but we were a power boat surrounded by masts so we weren't worried about taking a strike ourselves.

I guess having your TV fried while watching the Stanley Cup was mildly annoying.

[Topspin]

I'm not sure if this is the case for all airports, but, I believe there is a blue light called "Thor" that tower lights up when TS are in a certain range of airport. Ground crews vacate apron and seek shelter.

I guess these lucky lads didn't have that.

YVR has that system, blue lights all around the airport come on and every one is supposed to stop what they are doing and head inside.

I have never, ever seen those lights at YVR. Toronto all the time, but YVR all I see is Ops crash alarms and automated emails that start at BlackBerrys and work their way down through ground handling vendors. Usually by the time it reaches the ramp guys the Thor alarm is over.