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HeliJet S-76 Lighting Strike.


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So it turns out a friend of a friend was onboard. There was a loud crack/bang and the helicopter rolled to the side/pitched down violently. (A passengers version of violently may differ from crew mind you.) I speculate that when the instruments went blank from the lightning they lost all AP.

it was apparently quite startling and he legit thought he was going to die for a few moments. Once they descended and levelled off - everything was relatively normal. No alarming vibration levels he said. He and the other pax calmed down and the 8-10 mins of the rest of the flight seemed OK. There was a holy #### moment on the ground once everyone realized the condition of the tail.

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Edited to add that I just heard from a friend that works there and he said: "They initially lost all EFIS and both AP while IMC. UA recovery"
 

From PPRuNe!

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Scary stuff

Perhaps an example of helicopter induced lightning, a known phenomenon in north sea/sea of japan.

https://skybrary.aero/articles/helicopter-triggered-lightning-strikes

As if there weren't enough gotchas already with helicopters 😂

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Lightning Strikes can and do occur to helicopters in certain atmospheric conditions where there would otherwise be no similar electrical discharge without the presence of the helicopter.

The helicopter-triggered lightning strike phenomenon has been found to occur during operations over the North Sea between November and early April when there is usually little or no natural lightning activity in progress at the time. Over the past 20 years it appears that there have been 1-2 of these strikes each winter. It has also been considered significant that no strikes have been recorded to North Sea helicopters in summer months when the level of natural lightning activity is significantly greater than during the winter months.

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The part of the helicopter struck is almost always the main or tail rotor blades. Although the immediate effect on safety has so far appeared to be limited, the amount of damage caused has often been high with affected rotor blades found after flight to be beyond repair and rectification expensive.

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It has been found that, like fixed-wing aircraft, helicopters acquire a strong negative charge when they fly through air because of static charging. This is normally discharged once back in contact with the Earth’s surface, but if an aircraft comes close to a positively-charged region in a thunderstorm cell then there is potential for a lightning strike to be triggered to and through the helicopter. It is hypothesised that triggered lightning strikes may occur when a helicopter flies:

  • into a positively charged base of a Cb cloud
  • under the positively charged anvil of a Cb cloud
  • from a positively charged region of cloud to a negatively charged one.

It has been found that most, but not absolutely all, triggered strikes are positively charged and it is noted that positively charged regions of a Cb cloud are located close to the freezing level (the 0ºC isotherm) where the rate of change from the frozen to liquid moisture state, which leads to the separation of electrical charges, is at its greatest.

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