They recovered four, three of them AT the crash sites! How. The black boxes didn’t even survive.
Jet fuel doesn’t melt steel beams. But metal loses it’s strength while retaining its solid phase as it is heated. https://www.engineeringtoolbox.com/metal-temperature-strength-d_1353.html
This is the issue with laypeople speculating on complex engineering failures. The mechanisms of action that one might intuit from looking at a complex systems failure and the ones that actually cause it are oftentimes not related to or even opposite.
My favorite comment on this was a blacksmith heating a steel bar to a few hundred degrees and then pushing it around with his pinky. Also, the sheer number of people who don’t have any conception of what a blast furnace is or how it works, how oxygen and fire interact. Idk, I always thought the “jet fuel can’t melt steel beams” thing was absurd on it’s face. It’s such a silly premise. I’ve forged metal on backyard wood fires, you just need to set the airflow up to get incredibly hot fires.
Hey, you know the deal, no investigation, no right to speak. The link doesn’t talk about 9/11 at all, it talks about changes in metal strength at different temperatures.