. .I am fairly well sure that 99% of all aviators can recognise the smell of second hand cigarette smoke when they come across it. And of that 99%, I am sure 100% of them would be able to put 2 and 2 together and figure out that perhaps the previous crew had been smoking in their seats ! It is unfair and unresonable to drag engineering into a brawl between smoking and non smoking pilots. To read, SMELL OF SMOKE IN COCKPIT, SOURCE OF SMELL COULD NOT BE IDENTIFIEDin a log book smacks of an unhappy crew. To generalise, if this were the case and a genuine electrical fault had occured, often C/B's pop and things dont work ( in an extreme case, yes SR111 ! ). Lingereing cigarette smoke and it's associated smell does not constitute a technical defect, not in my book anyway ! Wake up guys and smell the flowers, if you don't like the stink, have a word with your buddies, don't try and take it out on the engineers who are generally too busy these days chasing cockroaches and sweeping out instrument panels after the last lot dumped their dinner all over it !