No they don't have primary "welded" alum structures, and alum is used because reduced weight is crucial to the task, and they have a track record of more then say 15? planes flying, they have extensive fatigue testing before manufacturing, they now have regular pre determined useful lifespan replacement procedures, and regular inspections beyond just visible. Its not an accurate comparison or observation.

Post weld heat treat of alum is problematic.

https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243

Last edited by jcc; 03/05/19 04:03 AM.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.