Originally Posted by
PlasticCabDriver
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?
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.