PIA 777-200 got hit by the lightning

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sayem
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PIA 777-200 got hit by the lightning

Post by sayem »

A PIA 777-200 got hit by the lightning when returning back from MAN to KHI, at about 30k feet. My dad just told me news few hours ago. Every thiong is ok apart from the 37 electronic components that were re-programmed after the landing.

Thats all I have, if you can add more feel free to do so.
Mujhay Fakhar ha Apni Parwaz par.


piafan
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Post by piafan »

What happens if 777 is hit by lightning up in the air at 35K feet?

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iqbal
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Post by iqbal »

i doubt anything happens structurally to the airframe - maybe it interfers electronically - as stated by sayem......anyone with any info on this one ?

Adnaan786
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Post by Adnaan786 »

Flying at 35000ft, you would think the designers would have thought about the possibility of lightning strikes... and of course they have! If you look carefully, all along an aircrafts airframe you can see antenna/aerial like things - these are called static discharge wicks. When hit by lightning these dispel the electricity back into the atmosphere. So being hit by lightning is nothing out of the 'norm'.

You might get a little interference on the radio, that's all.

(Here's an interesting fact: Most people think lightning travels from the sky downwards. In fact it starts from the ground and shoots upwards)

piafan
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Re: PIA 777-200 got hit by the lightning ....

Post by piafan »

sayem wrote:A PIA 777-200 got hit by the lightning when returning back from MAN to KHI, at about 30k feet. My dad just told me news few hours ago. Every thiong is ok apart from the 37 electronic components that were re-programmed after the landing.

Thats all I have, if you can add more feel free to do so.

If nothing is suppose to happen to aircraft from lightining. Why did 37 components required re-programming?....thats pretty dangerous if lightening impacts avionics.

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Falcon598
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Post by Falcon598 »

Adnaan786 wrote:
(Here's an interesting fact: Most people think lightning travels from the sky downwards. In fact it starts from the ground and shoots upwards)
Where did this come from. I have never head about this. I learned that there lightning is attracted to positive chareged molecules that lead to the ground or in the air, in case of spider lightning, and hits the ground since it is attracted to those molecules. In that case it would start from the ground at least the process since the molecules are here so then it would make sense, but otherwise it doesn't.

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Falcon598
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Post by Falcon598 »

Here is a link to the Wikipedia enclyopedia, which has an article on lightning:

http://en.wikipedia.org/wiki/Lightning#Lightning_facts

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PK773ER
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Post by PK773ER »

As far as i have heard and seen the static dischargers are on th wings. One single static charge can distroy your whole electronic system if system is not proper grounded or earth properly. When u r working in avionics workshop u cant repair any avionic system until u r connected to static discharger.

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Charliedelta11
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Post by Charliedelta11 »

see..the static discharge wicks to dispel most of the electricity back into the atmosphere , but a small portion of the electricity does effect the aircrafts navigation systems...a few years ago while landing in hkg , our plane ( A310 ) was hit by lightning which lead to a complete electrical failure , which resulted in a c9mplete blackout in the cockpit and in the cabin , the result was that landing had to be done on secondary backup instruments....but the 777 is a new state of the art aircraft..u need a heckj lot more to damage it in anyway...

Adnaan786
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Post by Adnaan786 »

Here are a few answers... :)

1.
If nothing is suppose to happen to aircraft from lightining. Why did 37 components required re-programming?....thats pretty dangerous if lightening impacts avionics
If an aircraft is struck by lightning some of its components may become magnetized, resulting in inaccuracies in the compass and certain electrical systems may fail.

However if the aircraft is well bonded (electrical potential along the airframe is made the same) and the discharge wicks are working properly, then this sort of problem is pretty rare.

2.
As far as i have heard and seen the static dischargers are on th wings.
Yes, your right. Their usually along the trailing edges of the aircraft - wings, tailplane, rudder, rear section of the fuselage.

3.
Where did this come from. I have never head about this. I learned that there lightning is attracted to positive chareged molecules that lead to the ground or in the air


What we see as lightning happens in a two-step process. Static electricity builds up between the earth and the cloud (something to do with the splitting of water molecules :)) and a spark in the form of an invisible lightning bolt comes down from the cloud.

Just before this bolt reaches the ground, it is met with an upward moving, positively charged spark. When the two collide, an explosion occurs as the return stroke travels up the bolt-the result: a visible flash called lightning.

SOURCE:
http://www.reachoutmichigan.org/funexpe ... tning.html

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Adnan Anwar
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Post by Adnan Anwar »

Falcon598 wrote:
Adnaan786 wrote:
(Here's an interesting fact: Most people think lightning travels from the sky downwards. In fact it starts from the ground and shoots upwards)
Where did this come from. I have never head about this. I learned that there lightning is attracted to positive chareged molecules that lead to the ground or in the air, in case of spider lightning, and hits the ground since it is attracted to those molecules. In that case it would start from the ground at least the process since the molecules are here so then it would make sense, but otherwise it doesn't.

Adnaan786 is right, lightining travel from ground to the sky. Airplane does not act as good conduit for electricity but can get hit by lightining as lightining travel at its path (lightning does not follow a designated path, it just travel once it starts where ever molecule provide a hospitable condition).

If plane gets hit lightinig the wicks just provide the path for it travel out of the plane (no better way to explain).

This can happen to Singapore Airline plane, Cathay Pacific plane or to a PIA plane. This is fairly normal to happen. Aircraft industry knows more how to handle lightning condition than people on this forum.
Adnan Anwar

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Falcon598
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Post by Falcon598 »

Adnaan786 wrote:

3.
Where did this come from. I have never head about this. I learned that there lightning is attracted to positive chareged molecules that lead to the ground or in the air


What we see as lightning happens in a two-step process. Static electricity builds up between the earth and the cloud (something to do with the splitting of water molecules :)) and a spark in the form of an invisible lightning bolt comes down from the cloud.

Just before this bolt reaches the ground, it is met with an upward moving, positively charged spark. When the two collide, an explosion occurs as the return stroke travels up the bolt-the result: a visible flash called lightning.

SOURCE:
http://www.reachoutmichigan.org/funexpe ... tning.html
That is kind of what I meant. The process at least starts in clouds in the air, but the ground is the second step. :D That is for ground-to-cloud lightning though.
Last edited by Falcon598 on Sun Aug 28, 2005 1:46 pm, edited 1 time in total.

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Falcon598
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Post by Falcon598 »

There are a couple different types of lightning, here are a few:

1. Cloud-to-Ground: Cloud-to-ground lightning is a great lightning discharge between a cumulonimbus cloud and the ground initiated by the downward-moving leader stroke. This is the second most common type of lightning. One special type of cloud-to-ground lightning is anvil lightning, a form of positive lightning, since it emanates from the anvil top of a cumulonimbus cloud where the ice crystals are positively charged. In anvil lightning, the leader stroke issues forth in a nearly horizontal direction till it veers toward the ground. These usually occur miles ahead of the main storm and will strike without warning on a sunny day. They are signs of an approaching storm.

2. Cloud-to-Cloud:Cloud-to-cloud lightning is a somewhat rare type of discharge lightning between two or more completely separate cumulonimbus clouds.

3. Ground-to-Cloud:Ground-to-cloud lightning is a lightning discharge between the ground and a cumulonimbus cloud from an upward-moving leader stroke. Most ground-to-cloud lightning occurs from tall buildings, mountains and towers.

4. Intracloud, sheet, anvil crawlers:intracloud lightning is the most common type of lightning which occurs completely inside one cumulonimbus cloud, type of intracloud lightning is commonly called an anvil crawler. Discharges of electricity in anvil crawlers travel up the sides of the cumulonimbus cloud branching out at the anvil top.

Some types start from the ground with the leader strokes upward movement as Adnaan786 said, that is ground-to-cloud. Others start from clouds with leader stroked downward movement. Also lightning can occur on any day even without the prescence of clouds.[/b]

Babushka99
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Post by Babushka99 »

Two good links regarding lightning strikes on aircrafts:

http://archives.vmacedonia.com/4429.htm

http://www.usatoday.com/weather/resourc ... anes_x.htm

Lightning strikes are limited to pretty much on the surface (skin) of the aircraft and as nature would have it - it gets discharges through the tail area and lightning mini-rods.