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The Therac-25 Incident (2021)

(thedailywtf.com)
449 points lemper | 2 comments | 27 Aug 25 06:57 UTC | HN request time: 0.408s | source
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napolux ◴[27 Aug 25 08:17 UTC] No.45036831[source]▶
The most deadly bug in history. If you know any other deadly bug, please share! I love these stories!
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NitpickLawyer ◴[27 Aug 25 08:23 UTC] No.45036858[source]▶
The MCAS related bugs @ Boeing led to 300+ deaths, so it's probably a contender.
replies(1): >>45036870 #
solids ◴[27 Aug 25 08:26 UTC] No.45036870[source]▶
Was that a bug or a failure to inform pilots about a new system?
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fuckaj ◴[27 Aug 25 09:36 UTC] No.45037315[source]▶
Not a bug. A non airworthy plane they tried to patch up with software.
replies(1): >>45037547 #
1. reorder9695 ◴[27 Aug 25 10:07 UTC] No.45037547[source]▶
The plane was perfectly airworthy without MCAS, that was never the issue. The issue was it handled differently enough at high angles of attack to the 737NG that pilots would've needed additional training or possibly a new type rating without MCAS changing the trim in this situation. The competition (Airbus NEO family) did not need this kind of new training for existing pilots, so airlines being required to do this for new Boeing but not Airbus planes would've been a huge commercial disadvantage.

[edit as I can't reply to the child comment]: The FAA and EASA both looked into the stall characteristics afterwards and concluded that the plane was stable enough to be certified without MCAS and while it did have more of a tenancy to pitch up at high angles of attack it was still an acceptable amount.

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2. fuckaj ◴[27 Aug 25 10:22 UTC] No.45037645[source]▶
I may have understood wrong but thought is possible to get into an unrecoverable stall?