Martin Gregorie
Same problem, no understanding of the system you use.
This is being addressed:
Google has a lot on that.
Maybe so are we, and occasionally we find a new pattern...
Not many people can even do that, they make 'gut' decisions.
The Natural Philosopher
I use a different port for ssh... Maybe it helps...
Indeed. In this:
So it's a single-point failure in disguise.
Not understanding the system you use is a point of pride for many people.
-- /~\ cgibbs@kltpzyxm.invalid (Charlie Gibbs) \ / I'm really at ac.dekanfrus if you read it the right way. X Top-posted messages will probably be ignored. See RFC1855. / \ Fight low-contrast text in web pages! http://contrastrebellion.com
It is a programming fault, the program SHOULD check for altitude, and it did not. Also as to airspeed it should use at least 2 sensors and do arbitration and disable itself and give a clear warning to the pilots if an abnormal condition occurred.
If it was me I would add a GPS and display speed over ground or even use that in arbitration. It is a design error, and I would sue the sh*t out of Boeing if it concerned me.
It is not always possible to in depth understand what you use, we know for example not exactly what is in that ARM chip in a raspberry... And what is matter and what is 'us' even (to get into philosophy) but basics like handling your car is required for a driving license. These days pilots get less and less real flying experience and more and more is done on autopilot.
Now there are automatic subways.. next there will be automatic airplanes, and many will die before all the bugs are out.
Airbus had similar problems in the past with 'fly by wire'.
Not so long ago an other passenger plane fell out of the sky near Amsterdam airport, frozen airspeed sensor IIRC. Totally insane in a world with GPS. It is a re-occurring problem .
Some pilots are worse than bad bus drivers, and sometimes loaded with alcohol.
Worse - an undocumented single point of failure. Here are some links:
The article I first saw in The Register:
'MCAS' in The Register article links here:
... which describes the control system and why it was fitted to the 737- MAX. From it "[Boeing] quietly added a new system" points here:
which gives an airline pilot's view of the way Boeing introduced and documented the new autotrim system.
-- Martin | martin at Gregorie | gregorie dot org
If you want to be sure, you need at least three sensors and a majority vote to determine, not that that there is an anomaly, but *which* sensor is anomalous and should be ignored. Error-correction as well as error-detection.
I read a very good aeroplane-based thriller. A plane started climbing and diving, causing a lot of injuries (and a LOT of puke!) and a few deaths. The airline company needed to preserve its good name and find out as fast as possible what had happened, amid accusations that there was a design fault.
The pilot and all the aircrew buggered off to their home country as soon as they landed, so they couldn't be interviewed.
Analysis of the black box showed some anomalous readings for a sensor which detected the position (retracted/extended) of the slats, and gave a warning.
After a lot of testing, and a very dramatic demonstration to a trouble-making news reporter, they identified what had happened:
- a duff OEM (fake!) sensor had given a false warning; there was only one sensor, so no "best of three" was possible
- the plane was on autopilot, but the pilot tried to override the autopilot, in the mistake belief that the autopilot was wrong and he was right
- the pilot who had control of the plane at the time was the real pilot's son who was not approved to fly that type of plane but was allowed to take control at quiet times
- a test pilot from the company was able to provoke the problem by doing what he suspected the pilot had done, and demonstrated that all he had to do was to let go of the controls, and the autopilot immediately corrected things and resumed level flight
Result: company vindicated, reputation intact.
"NY" wrote
Yes, that is better, IIRC Concorde had 3 systems and arbitration.
Of course 2 sensors with vastly different values would also indicate something is wrong. Sometimes I think the software was written by some intern...
From the other links posted here Boeing does not seem to think very high about pilot capabilities... "No need to tell them about the system, too complicated for them'.
Joke among pilots: The cockpit of the future has a pilot and a dog?the pilot?s job is to feed the dog, the dog?s job is to bite the pilot if he tries to touch the controls. ;-)
-- -michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
Michael Crichton's Airframe to be precise. Good precis.
-- Steve O'Hara-Smith | Directable Mirror Arrays C:\>WIN | A better way to focus the sun The computer obeys and wins. | licences available see You lose and Bill collects. |
Read the linked stuff a bit closer: the LionAir plane was quite high and fast - certainly at climbout speed - when the autotrim jumped in. In any case it wasn't and should not be interested in altitude because the condition it was supposed to prevent is more likely to occur both lower and slower than typical high altitude cruise.
This is more likely to be a design error rather than a programming fault, because it couldn't handle a single AOA sensor failure despite having a pair of AOA sensors fitted. I say design, because the system test regime will (and should) be created from the system specification rather than the code - and clearly there was no acceptance test for operation with a failed sensor or, as seems likely, nor for automatic disengagement if both sensors fail.
Nope - by design this time. The autotrim was *designed* to correct an AOA excursion without telling the pilots. Remember that the pilots were intentionally not informed that it was installed, hence no training about its effect or how to disable it.
That will certainly happen: just give it time: the US justice system is often very slow and Boeing will be fighting it all the way to the courtroom door. Its just lucky for Boeing and their passengers that this happened with fewer than ten 737-MAX in service.
-- Martin | martin at Gregorie | gregorie dot org
Ah, I wondered if anyone would work out which book it was from the description.
No. It still requires typing sudo before anything dangerous can be done, so its very far from being root only.
---druck
I love that scene near the end when the test pilot is demonstrating to the journalist what happened, and warns her that it will be very bumpy, but she tries to make out that she doesn't need air-sickness tablets. He throws the plane around and as it porpoises, she pukes, unlike everyone else who has taken counter-measures. And then he demonstrates that all he has to do is take his hands off the controls and the autopilot instantly corrects - so no design fault in control surfaces or autopilot.
And the scenes with the male reporter are instructive: he knows nothing at all about the subject but he just repeats whatever the interviewee has said, as a question, as if to imply scorn and derision at the answer, and put the interviewee on the defensive. One trick, but it works well. And he is parachuted in to ask the scripted questions, get the reactions he wants, and then buggers off to the next assignment.
That's the crucial point: it has the "protective cover" over the dangerous "big red button" commands, so you have to consciously think "I need to use sudo - so take care". It's not necessary to get users to prove that they know the root password, unless you think that they will be malicious as opposed to just absent-minded.
I'm not sure that I know the (default) root password of my pi, since I don't remember being asked to choose one during installation.
On 12/12/2018 17:56, Jan Panteltje wrote: [Snip]
[Snip]Speaking as both a pilot and software engineer on the A330/A340 programme.
1) Ground speed is irrelevant to flight, only navigation. It's airspeed which is important, and isn't measured by GPS. 2) GPS far less than perfect when used in aircraft, and is only ever used in addition to other navigation and precision approach systems.Some armchair internet commentators talk a lot less sense than drunks.
---druck
There isn't one / it's not set.
That's interesting. I'd have thought that with a good aerial and no obstructions so you can see lots of satellites you should be able to get very good results.
My phone varies between about 20m and 5m radius of error for lateral movement. Not sure how accurate it is for altitude. I sometimes find that I get a systematic error which causes a track to follow the twists and turns in a road perfectly - except offset by maybe 100 m.
What are the current "other navigation and precision approach systems"? Is it still NDB, VOR and ILS, or have things moved on since I used to "fly" planes in MS Flight Simulator?
And have you checked for "port knocking"?
Ah. Something I did prompted me for "the password" (I'm not sure whether it explicitly said it was for root) and I tried and the Pi password but to no avail. A sudo prefix still works without prompting, so I can't think what it was that prompted me for the password.
Probably the botnet installer ;)
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.