For some crashes that have interesting causes (at least from an engineering perspective) beyond "maintenance failed to identify a problem before takeoff" or "pilots fail to identify problem or take wrong actions", I strongly recommend the articles on TWA 800 (1996) [1] and the near-crash of SmartLynx Estonia 9001 (2018) [2]. The first goes into great detail exactly _how_ the FAA discovered the root cause, whereas the second one involves a logic oversight in the flight computers of a modern Airbus plane.
[1]: https://admiralcloudberg.medium.com/memories-of-flame-the-cr... [2]: https://admiralcloudberg.medium.com/the-dark-side-of-logic-t...