On a sunny day (Sat, 18 Sep 2021 23:28:04 -0700 (PDT)) it happened Flyguy
<firstname.lastname@example.org> wrote in
>On Saturday, September 18, 2021 at 11:23:16 AM UTC-7, Jan Panteltje wrote:
>> On a sunny day (Sat, 18 Sep 2021 10:25:44 +0100) it happened Martin Brown
><'''email@example.com> wrote in <si4bao$1rp4$2...@gioia.aioe.org>:
>> >How to do it optimally has been known for around a couple of decades.
>> >The old traditional way was to try and avoid all critical in service
>> >failures by replacing still working parts before they reached MTBF.
>> >We christened it causative maintenance since it was pot luck whether or
>>not the damn mainframe would come back up again after a manufacturers
>> >"preventative" maintenance.
>> In my TV days we would run shifts and if something failed fix it ASAP
>> there was also some redundancy in equipment so you could divert operations.
>One day there was some genius who decided to reduce interruptions in
>> the broadcasts to make a 'preventive maintenance' group, and to work those
>> Basically with Ampex quadruplex video recorders that meant taking one apart
>and putting it back together again.
>> The usual things we already did on schedule, like replacing recording heads
>> Disassembling and putting back together solid state electronics does not really
>> 'if it ain't broken do not fix it;
>> Anyways one machine started to produce little black spots every now and then
>in the picture,
>> It was sidelined, and several engineers had a go.
>> One evening I had the late night shift, not much to do,
>> everything worked, so I decided to have a look at that machine,
>> Took the scope cart, Tek, could detect strong impulses everywhere, was midnight
>and we went off air (in those days),
>> so I wrote in the book for the next shift 'seen pulses everywhere, looks like
>a shield is lose'.
>> My boss, it was his turn next morning, he read that remark and spend the whole
>day taking the thing apart, no luck.
>> Next day it was my shift, took all circuit diagrams, scope and went for it.
>The pulses reminded me of some tacho signal used,
>> found the pulse generator and followed its output via a coax cable that send
>it to an other unit,
>> PL259 connector, was sort of lose, screwed it back on tight, problem fixed.
>10 minutes.... Went back with all the books and scope card and said: Hey guys,
>let's go get some coffee.
>> All the faces there in disbelief.. OK, I said I will show you and reproduce
>> So how did that cable come lose? The preventive maintenance group had forgotten
>to tighten that PL259 connector.
>A lot of this theory depends upon the deterministic nature of systems, namely
>machines behave in predictable ways that we can detect if we are smart enough.
>But what if this is not true? What if systems have an unpredictable component
>that we don't know about? This has happened, for example, in jet engines,
>which are inspected very regularly with sophisticated instruments.
>This happened to United flight 232, a DC-10 which had a catastrophic engine
>failure (https://en.wikipedia.org/wiki/United_Airlines_Flight_232). The cause
>of the failure was a metallurgical anomaly in a stage 1 fan disk.
>Chaos theory covers this type of situation. If you are blind folded, or walking
>in a fog, you will be OK most of the time. But, in rare circumstances,
>you might walk off o, f a cliff. All of the data you could collect prior to
>the catastrophe will probably indicate that there is nothing to worry about.
>But that would be wrong, just as it was for Flight 232. Sometimes you just
>have to shrug and say "It's better than nothing" which it might be.
>While flying I am dealing with similar probabilities. Most of the time it works
>out fine, but sometimes it doesn't. A couple of years ago a good friend
>of mine, who was a very experienced pilot, died doing a routine flight maneuver
>that he had done tens of thousands of times before. Chaos theory caught
>up to him.
Sure, unexpected things happen, try to keep a TV station (we had 3 channels)
without interrupts running.
Or a studio production with many cameras recorders, audio,
artists waiting, freaked out director... the show must go on...
You cannot sell minutes of black .
It is bad practice to - as a zombie - take things apart and put it back together for the fun of it.
There _is_ of course an area for preventive maintenance, but that must be done
I don't give a shit about chaos theory, what COUNTS is that you know the stuff to component level
and can fix it.
Planes have fallen apart due to metal fatigue... pressurization and de-pressurization stress, birds...
suicidal pilots, bad programming of the computahs, pilot errors, bombs, what not.
address those issues and you do something .
I do not like pilots that just walk into a plane 'I am the Pilot' without walking around it and having a good look at everything.
Now take my experience in the F100 Super Sabre, well no reason to repeat it here, posted about that long time ago...
So many lives at stake...