I think what it lead to was someone's lack in testing. Such a big aircraft which have to load hundreds of people just crashed in 2 min, it's really shocking. Either there's a technical issue which was missed during the time of testing or either someone intentionally made a mistake, I'm just coming across such kinds of news giving one reason or the other but it's really strange that such a big incident is made. The luck remained with the guy who survived but I think the focus should on those people instead who died while the plane crashed and with those medical students who were there in that building and having there lunch. Losing hundreds of lives isn't a small deal.!