Essentially, we still don't have a viable replacement. The FAA was tasked with coming up with one by the end of 2018, but has been extended to 2021.
Why would an engine require leaded gas, you ask? Because it helps keep the valve seats from degrading. We have other anti-knock additives, but nobody has figured out a replacement for the other properties that lead has.
And since aircraft are usually extremely long-lived, we'll be stuck with this problem until a substitute is found. Merely certifying new engines that don't require lead won't solve the problem because of the remainder of the fleet that does require leaded gas.
Conformal coat really is the saving grace for tin whiskers. It's not perfect, a whisker can push through sometimes but then the whisker has to push back through the conformal coat again which is much harder.
About leaded solder and the environment: "Current alternatives are worse for the environment",page16 https://nepp.nasa.gov/whisker./reference/tech_papers/2011-ko...
Did you read their specs?
There's a small part about whiskers that already convey enough meaning:
> UNACCEPTABLE WHISKER
> A whisker is a slender needle-shaped metallic growth between a conductor and a land. Typically the result of mechanical stresses in high tin compounds, it is a reliability concern."
'Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."'
It doesn't add anything to the discussion. And in this case it was very clear that the OP read the article and just missed that part.
Your comment would have been just as informative and less snarky if it was simply:
There's a small part about whiskers that already convey enough meaning:
> UNACCEPTABLE WHISKER
> A whisker is a slender needle-shaped metallic growth between a conductor and a land. Typically the result of mechanical stresses in high tin compounds, it is a reliability concern."
> 'Please don't comment on whether someone read an article. "Did you even read the article? It mentions that" can be shortened to "The article mentions that."'
Not an article, but specs. You read specs carefully, you don't skim, especially to write long paragraphs about your personal experience
> And in this case it was very clear that the OP read the article
I disagree. Not read, skimmed at best.
> and just missed that part.
I agree: the most important part was indeed skipped.
You're factually wrong here. So the question would be where did this go off the rails?
The issue with whiskers is that they grow over time (which is why I mentioned 'point in time'). I didn't see anything in there about solder alloy selection or any other mitigation.
https://nepp.nasa.gov/whisker/
I thought they were just one of those low probability items until a Sunday morning when I was running live audio for a church service. Singer was mid verse and BOOOOM! Huge booming sound over speakers startling everyone into nervous laughter. I opened the cable up afterwards and sure enough found these alien crystalline structures growing between the conductors. It had shorted and even the little bit of current in the microphone vaporized about a mm of material.
Really really weird and I'm certain kept some folks up at night over the years.