Views : 1,059,482
Genre: People & Blogs
Date of upload: Apr 22, 2019 ^^
Rating : 4.835 (742/17,217 LTDR)
RYD date created : 2022-04-09T04:00:47.566422Z
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Top Comments of this video!! :3
A note about how aviation looks at mistakes in the US: we have a great program called the ASAP program where if you generally make a mistake (ie not intentionally breaking a rule or being negligent), you can self report to the FAA. They then look at it with representatives of the company and the workers union to determine if it was actually a mistake without a name attached to the report to keep it anonymous. If it was determined to be a mistake and the ASAP is accepted, the FAA cannot take action against the person who made the mistake. The number of people willing to admit to mistakes has increased since implementation and industry wide training has gotten better because of this.
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What about the math error at the Savannah River nuclear plant that was regularly cracking the pressure vessels. Everyone kept checking the materials used, and engineering practices, but no one verified the actual operating pressures of the vessels, and it turns out that they ran for 40 years at 115% power levels because some engineer had a slide-rule error during its initial construction documentation.
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28:05 bit of a correction: that happened to the USS Yorktown, which at the time was a Ticonderoga class cruiser. The story changes a bit every time I hear it but essentially some sailor was working on the radar, typing in gates so that it doesnât flag every seagull or cloud as a target. One of the gates didnât apply in this situation so he put a zero in it. If he had left it blank or written null or anything else, the computer had a check to filter out non number inputs. However, the check read 0 as a valid number to enter into its equations, at which point it divides by zero and the system, running Windows NT, freaks out and shuts down. This computer not only ran the radar, but also propulsion and navigation. The ship ended up dead in the water for about three hours
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13:46 the lone star joke he threw in there was brilliant.
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In re: spacecraft -- About 35 years ago, while in college, I was working in a cooperative education job for eight months at RCA Astro-Electronics. The department I was working in was updating testing software created for the TIROS-N satellites for the Advanced Tiros N satellite, which had more instruments on it. The point of the testing software was to make sure that the instruments wouldn't shift too much during launch. To do this, they would measure with lasers the precise location of the instruments on the spacecraft put on a shaker table simulating launch, vibrate and then remeasure the positions, and put all the figures into this program to check if it was in specs. Well, on modifying the program (in FORTRAN, btw), I notice that it had a subroutine to calculate the difference between signed numbers. And here's how it did it: First it took the absolute value of the difference of the absolute value of the two inputs, and then if the inputs had different signs, put a minus in front of the result. Essentially Z=ABS(ABS(X)-ABS(Y));If ((X<0) and (Y>0) ) or ((X>0) and (Y<0)) Z=-Z Well, hang on! If X and Y were different signs, those results were just wrong! And FORTRAN, like all computer languages, has no trouble with signed arithmetic. It just simply should have been Z=ABS(X-Y) I blinked a couple of times, showed it to my boss (cause I was just a college student, and wanted to make sure I wasn't misunderstanding something) And he agreed it was just totally wrong. So while it may never have happened that something crossed over an axis during the shake, I'm glad I was able to potentially save a multimillion dollar spacecraft from potentially being useless.
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One of the more funny long nerd talks I have seen in full in a long time. What disturbs me is that companies are reluctant to give away how mistakes were made. I think companies easily could obfuscate sensitive portions but still give away generic parts of the error. That would help not only the company itself but human beings as such. But sadly, often cause of errors are not even communicated within the company itself :-(
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@blackpenredpen
5 years ago
What an honor to be mentioned by you, Matt! Thank you!
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