I attended at a training concerning airborne software and the coach remarked that despite at the normal courts, when an aircraft crashes and the authority investigates, a manufacturer is guilty for that accident until innocence is proven that the manufactured device did not produce the defect causing the crash.
I hoped to find on the web some reference to this "guilty until proved innocent" rule, but I cannot. Do you know where I could find some info about that?
I'll assume you're talking about an English common law jurisdiction (UK, US, Can, Aus, NZ etc.). In those places it's always "innocent until proven guilty", the key thing being what "proven" means.
You have to separate criminal liability, breaking of a law in the criminal code, from civil liability (a civil wrong, or "tort" in English common law). The criminal liability standard of evidence is "guilty beyond a reasonable doubt" at trial, and tort liability standard is "guilty based on preponderance of evidence" at trial (that is, more likely than not in the assessment of a trial jury (in the US) or a judge).
So a manufacturer or an airline is only exposed to criminal liability where an incident involved the violation of a criminal statute. You can't throw the "company" in jail, so an individual has to be on the hook and so the authorities would have to identify a criminal code violation committed by an officer or employee of the company, and it would be that employee or officer that would be going to jail (for something like violation of a criminal negligence statute). And in that case the standard is guilty beyond a reasonable doubt.
In the case of civil liability, the corporation itself, or potentially its officers personally, are on the hook, the penalties being solely financial (employees are normally shielded from civil liability in a limited liability corporation) and the "preponderance of evidence" standard of guilt applies.
The thing is, both of these conditions require a court trial. Either government prosecutors go after individuals (officers of the company or employees) for criminal violations that include fines and/or jail time for those convicted of criminal acts, or non-government individuals that have been harmed (families of passengers killed for example) go after the corporation in civil court, and the corporation is only guilty of a tort (civil wrong) if a judge or jury finds them guilty.
So in both situations it's "innocent until proven guilty"; the difference is in who the accuser is and what the standard of evidence is.
Now, outside of the Anglosphere, all bets are off, and you may very well find places where guilt is assumed and company has to prove its innocence to get off the hook for either criminal or civil liability.
Just to set things straight, accident investigation performed as per ICAO Annex 13 (Aircraft Accident and Incident Investigation) and criminal investigation regarding an aviation accident are separate processes.
The "Annex 13" investigations aim to find out why an accident happened, so it is focussed on reason(s). The purpose of this is to prevent repeating mistakes, whatever they might be.
Criminal investigations on the other hand are usually based on a presumption someone might be guilty of, say, negligence or such, but they do certainly not presume guilt. The purpose of criminal investigation is to establish evidence of whether or not there is guilt or liability in a case.
None of the instances responsible for investigations in any civilized society make presumptions or judgement of guilt. The simply gather evindence. Now, interrogative methods might make it seem like the investigator thinks the person under investigation is guilty, but no good investigator will allow oneself to fall into that trap. Guilt or liability is established in a court of law.
It is my firm recollection that Annex 13 investigations are generally inadmissible as evidence in a court of law. The reason for this is simple: to secure the access to truthful information. If there was a chance what a whitness said to accident investigators might be used against oneself in court, they probably would prefer not to say anything. At worst, they might end up down right lying to hide their role or liability in an accident.
To be presumed guilty until proven otherwise just does not happen in civilized countries. Sad to say this does not include all nations...
a manufacturer is guilty for that accident until innocence is proven that the manufactured device did not produce the defect causing the crash.
No, someone has found some evidence of a "defect" after the crash and filed a lawsuit on these grounds. How sound this evidence is, and what exactly is the "defect" doesn't matter at this point: the lawsuit was filed and the manufacturer will have to defend themselves. They are still innocent until found guilty.
I put the word "defect" in quotes here because the legal definition is much broader than what people usually think. For instance, a coffee heated to 88 °C was found defective in Liebeck v. McDonald's.
