I'm self-loading freight.... now, an aged bitterly frustrated (by youthful circumstances beyond my control) wannabe from following the career I was designed for, which was to fly professionally like you guys. Then, late in life when I was able to afford to go for a PPL and just about to solo I dissected my aorta. That was quite a bad-hair day and ended my flying totally.
Meanwhile I had become an academic lawyer with a specialist interest in criminal law, and have focused (and published some papers in learned journals) on the criminal law aspects of flight safety. Now retired, I still read avidly and still do try to think about the theoretical basis of safety.
I watched the video that started this thread with interest and surprise. It is really ugly. As far as I can recall, nowhere in anything that I have read does it say that one may take off with an ice-contaminated aircraft "provided that.....". The quotations by UUWUDZX (posting 208) from the Airbus manual seems to sum up what I always thought the situation to be.
During my short-lived flying training I recall my instructors teaching me that, while there may be some interest in defining the different forms which ice can take, they all have one thing in common: anywhere on an aircraft, ice is to be presumed to be incompatible with safe flight, and it is certainly poor airmanship to try to take off without determining that there is none.
Reading what I have done on this thread, something else comes across forcefully to me. The fact that some contaminated aircraft have successfully taken off and flown while others have failed actually highlights the dangers of ice: its effects are unpredictable, and accordingly to be avoided. One contributor to this thread pointed out that even loose dry snow can hide problems. Empirical ad hoc research into whether one can successfully take off or not thus seems to be of no value, and to be discouraged.
So may I ask: aside from the cost of the process and delay, for what reasons would a pilot with passengers on board and who was aware of ice decide not to de-ice? If the reasons are only cost and delay, then surely pressure from the accountants must be resisted?
The impression I have formed in seeking to understand some of the theory underlying safety is that one would always try to avoid having to make subjective and discretionary judgements on safety-critical issues. A yes-no, black-white, on-off situation is preferable to one in which one has to use one's judgement, and this forms the basis of the cliché to the effect that if there's a doubt then there is no doubt. If this is correct, then am I also right to think that the typical professional pilot prefers to fly as routinely as possible, but trains for emergencies in a simulator hoping that the skills so acquired will never be needed? If this analysis is correct, why would pilots want to be in a situation in which they would look at ice and say, "Well..... I wonder.... maybe.... oh, we'll give it a go"?
From a legal point of view, my interpretation of all the "endangering" legislation I have looked at is that even if one succeeded in taking off and flying then one would still have been committing an offence precisely because the effects of ice are unpredictable. It would then be sufficient to prove recklessness (crudely, knowing disregard of the dangers) if one knew of the ice on the airframe; or if one knew that, in the prevailing conditions, there might be ice but decided not to check. In this case, one should be deemed to have known that there was ice (even, in fact, if there was none...... which is an interesting thought -- in addition to other forms of ice, we now have virtual ice!).
As a matter of prosecution policy, it seems that the point of view of the industry with all its muscle is one of "heads we win, tails you lose": if the aircraft took off and flew (I won't say "safely"), a prosecution is unlikely as a matter of policy and anyway the probability is that nobody significant will have noticed. If the aircraft crashed, then who's likely to survive to be prosecuted........?
The criminal law is a blunt weapon, but if its use is for deterrence then the policy behind prosecutions is flawed. I'd like to offer a comment or three.
Early on in the thread (eg pudoc, posting #28, is typical) some contributors remarked that they would intervene if they were passengers. The trouble with this is that it's too random and uncertain -- it presupposes a knowledgeable and confident passenger at a window seat.
On the other hand, why not formalise the situation? May I ask: is there any SOP which requires ground personnel proactively and routinely to draw the commander's attention to safety-critical issues regardless of whether the commander is or may be aware of the matter? If one assumes a worst-case scenario, the crew may (without necessarily being at fault) be unaware of ice; do ground personnel have no duty to raise the alert? As the final decisions are the commander's, receiving a formal alert would put great pressure on the commander to address the matter.
My thinking here is that one problem is, as I see it, that human beings have the capacity to talk themselves into doing the most unreasonable things. My lay understanding of CRM training is that this is addressed. Something is sometimes needed to break the causative chain before it matures into catastrophe. Would it be too invasive of the commander's discretion if someone on the ground had the authority to delay departure until either the aircraft has been de-iced, or the commander has explicitly overruled the delay?
Apart from anything else, this would create solid evidence of recklessness if it was needed in subsequent criminal or disciplinary proceedings.
But the penal sanction can be a pretty blunt weapon and is easily used inappropriately. During my working years as an academic, I realised that we don't always ask what, precisely, we hope to acheive by the use of the penal sanction (and I include internal disciplinary proceedings). I would have thought that here it is not to exact vengeance, but to prevent the harm from happening. The fact that more people than just the pilot would now be involved suggests to me that the criminal sanction can be exploited to create a culture of "I do not and never would do a thing like that, nor should anybody else, and the intervention of the ground personnel has been helpful in securing that objective standard."