You should find one of the excellently detailed reports of the incident and study it more closely. Almost everything you state above is wrong.
The two main causes were
(1) failure to act on a known problem with the airspeed sensor design on behalf of the plane manufacturer and the airline and (2) failure to train the pilots on how to handle this known failure mode.
I just came across this EE Life article, so here is my entry.
Years ago, my parents went on a vacation and made good friends with a gentleman by the name of Dick Mendenhall. Dr. Mendenhall was a giant in the early years of vacuum tubes (valves) at Bell Labs, and he had the scars to prove it. He had lived through at least one accident involving high voltages and metal lab floors. He was missing toes on both feet, and the feet themselves were deformed, as a result of those accidents.
Some of you might remember the very powerful AM radio stations across the border in Mexico. Dr. Mendenhall designed the power tubes that ended up in some of those 500 kilowatt radio transmitters, back in the 1930s. They were big, 8 foot long vacuum tubes, with non-thoriated filaments that dissipated over 15KW of filament power alone, per tube.
Dr. Mendenhall's daughter or granddaughter ran Jim Henson's Muppet Lab. FYI.
I had one of those, a '58. It was a little lever between the driver and passenger. 12 o'clock was main, between 1 and 2 was off, and 3 o'clock was reserve.
My mates found out about it and used to turn it off surreptitiously with their feet. So I ran out of power in the middle of a busy main road out of town once and did some snappy lane changes so I could pull over if necessary...this was noticed by some passing cops who pulled me over and chewed me out good and proper. With my mates sniggering away....
First, about engineers soldering and such: some engineers actually do work with reality instead of passing that all off to others. Next, it is entirely possible to work on live circuits and not be injured, BUT it takes more concentration than many people are able to have. Much more than the millisecond MTV generation could ever muster.
But the biggest engineering disaster was not an exciting explosion, although that option did exist. WE built some fairly complex boxes to provide power for two film cameras and four lights, for recording crash tests inside a vehicle. Two 20 amp camera loads and four 15 amp lamp loads, all from a linear regulated supply powered by three 12 volt 7.5 AH gell cells. Every thing worked, almost, except that the contract engineer who designed it overlooked the voltage drop at 100 amps. So instead of providing the specified 28 volts regulated at 100 amps, for 15 seconds, it would drop down to 25 or 26 volts, and the cameras would not come up to speed correctly. The fault was found to be just a bit to much voltage drop in a whole lot of different places, including too many 15 amp connectors. So the customer would not pay and we had a whole load of very expensive anchor blocks. THAT was a disaster!
F6 (Operator's Choice ...) was pretty scary, but how about the first one listed! I think I read about this one before.
"Eleven Therac-25 therapy machines were installed, ... The
Canadian Crown (government owned) company Atomic Energy of Canada Limited (AECL)
manufactured them. ... The software control was implemented in a DEC model PDP 11 processor using a custom
executive and assembly language. A single programmer implemented virtually all of the
software. He had an uncertain level of formal education and produced very little, if any
documentation on the software. ... Between June 1985 and January 1987 there were six known accidents involving massive
radiation overdoses by the Therac-25; three of the six resulted in fatalities. The company did not
respond effectively to early reports citing the belief that the software could not be a source of
failure. Records show that software was deliberately left out of an otherwise thorough safety
analysis performed in 1983, ... After a large number
of lawsuits and extensive negative publicity, the company decided to withdraw from the medical
instrument business and concentrate on its ___main business of nuclear reactor control systems.___ ...
Great! Just let them move from killing one person at a time to endangering a multitude! They shouldn't have been allowed to do janitorial duties after what they did!
Back in high school, working on a balky scoreboard in the gym, I asked if the power was off and was told yes. When I reached in to pull a fuse to check it, I got zapped. I distinctly remember my body's reaction: my arm pulled back with the fuse still in my and and flung it across the gym without even thinking about it! Didn't even fall off the ladder!
NASA's Orion Flight Software Production Systems Manager Darrel G. Raines joins Planet Analog Editor Steve Taranovich and Embedded.com Editor Max Maxfield to talk about embedded flight software used on the Mars on EE Times Radio. Live radio show and live chat. Get your questions ready.