Weather leaves 300 oil workers stuck in North Sea
another AS332L helicopter suffered a high energy lightning strike. This Norwegian aircraft, LN-OLB, was inbound to Bergen on the 27 February 1996 when it was struck, resulting in heavy airframe vibration. The commander elected to continue to land at Bergen where subsequent inspection revealed marked damage to its main rotor blades, with further damage to its hydraulic system components and airframe, although the tail rotor showed no evidence of lightning attachment
Oddly it doesn't seem to figure in the Norwegian official list of reports
https://www.nsia.no/Aviation/Publish...ge=1&lcid=1033
Other than G-TIGK which had arguably sub standard (as in an inappropriate certification standard) tail rotor blades - and 332L tail rotor blades were subsequently improved - I don’t think there have been any loss of life or loss of aircraft incidents from TL. However each strike is VERY EXPENSIVE as it generally requires replacement of blades, head, main rotor gearbox etc. And can be pretty alarming when you see the damage.
I have always thought the forecasting algorithms were pretty blunt but then again I can’t design a better one! My own TL strike was from stratus cloud, absolutely no turbulence at all. Then zap. A pretty minor one but resulted in a burnt rotor blade.
With regard to the current publicity there is “defence” that de-icing wouldn’t help. But surely if you can climb above -2C then you are clear of the TL zone. Maybe it depends on the specifics of a particular aircraft’s de-icing system?
I have always thought the forecasting algorithms were pretty blunt but then again I can’t design a better one! My own TL strike was from stratus cloud, absolutely no turbulence at all. Then zap. A pretty minor one but resulted in a burnt rotor blade.
With regard to the current publicity there is “defence” that de-icing wouldn’t help. But surely if you can climb above -2C then you are clear of the TL zone. Maybe it depends on the specifics of a particular aircraft’s de-icing system?
Other than G-TIGK which had arguably sub standard (as in an inappropriate certification standard) tail rotor blades - and 332L tail rotor blades were subsequently improved - I don’t think there have been any loss of life or loss of aircraft incidents from TL. However each strike is VERY EXPENSIVE as it generally requires replacement of blades, head, main rotor gearbox etc. And can be pretty alarming when you see the damage.
I have always thought the forecasting algorithms were pretty blunt but then again I can’t design a better one! My own TL strike was from stratus cloud, absolutely no turbulence at all. Then zap. A pretty minor one but resulted in a burnt rotor blade.
With regard to the current publicity there is “defence” that de-icing wouldn’t help. But surely if you can climb above -2C then you are clear of the TL zone. Maybe it depends on the specifics of a particular aircraft’s de-icing system?
I have always thought the forecasting algorithms were pretty blunt but then again I can’t design a better one! My own TL strike was from stratus cloud, absolutely no turbulence at all. Then zap. A pretty minor one but resulted in a burnt rotor blade.
With regard to the current publicity there is “defence” that de-icing wouldn’t help. But surely if you can climb above -2C then you are clear of the TL zone. Maybe it depends on the specifics of a particular aircraft’s de-icing system?
If you can get below -10°C then red areas can be treated as amber, which would most often be achieved by getting high enough to get that cold, so the S-92 can do this IMC if it has the RIPS working, 175 needs to be VMC below -10° (like the Puma) so a bit more limited in trying that option. Question always is though, if I am flying above a red area because it is < -10° outside, what happens if I suddenly have to descend?
I’m sure a CHC S-92 from a few years ago had one. The path of the current from point of entry through the blade, right through the MGB, down the TR drive train, through those GBs to the point of exit could be clearly seen. As you said, complete replacement of the entire transmission.
If you can get below -10°C then red areas can be treated as amber, which would most often be achieved by getting high enough to get that cold, so the S-92 can do this IMC if it has the RIPS working, 175 needs to be VMC below -10° (like the Puma) so a bit more limited in trying that option. Question always is though, if I am flying above a red area because it is < -10° outside, what happens if I suddenly have to descend?
If you can get below -10°C then red areas can be treated as amber, which would most often be achieved by getting high enough to get that cold, so the S-92 can do this IMC if it has the RIPS working, 175 needs to be VMC below -10° (like the Puma) so a bit more limited in trying that option. Question always is though, if I am flying above a red area because it is < -10° outside, what happens if I suddenly have to descend?
Its coming up to 10 years since I retired but when the whole TL thing was being investigated, an analysis of all NS lightning strikes was carried out and every one of them was with an OAT of +-2 degC. So if the current rules require going to -10c then that seems extremely over-cautious. What science is that based on?
As to the need for an unexpected descent then one should bear in mind that safety is all about probability, not absolutes. For many years people flew for thousands of hours in the “danger zone” and there were just a few strikes a year. So if you have to descend through the “danger zone”, taking 2 or 3 minutes to do so, the probability of getting struck is extremely remote and much less likely than other catastrophes.
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