EC225 crash near Bergen, Norway April 2016

[Lonewolf_50]

Originally Posted by riff_raff

Let's take a look at an example of where C64 gears may have made a huge difference. Consider the 2009 S-92 accident where the main gearbox TTO spiral bevel pinion suffered catastrophic plastic failure of the gear teeth from elevated temperatures during loss of lube operation after just 15 minutes. One could argue that if the TTO spiral bevel gears were made of C64, with its much higher temperature capability, they might have continued to function long enough to prevent the crash.

Good example, I've heard a similar point being made about gears with Isotropic superfinishing but am not sure if they could claim the loss of lube protection ... but the point about changes in manufacturing requirements factoring into cost is worth keeping in mind. (Does AH/Eurocopter use ISF to their planet/sun gears in the epicyclic module?)

Here's a good NASA technical paper on the subject of C64 gears if anyone is interested.

Thanks for the link and the table provided.