On the tarmac for some three hours looking into the problem. does that sound as though they knew there was something they needed to investigate? obviously there was something very serious going on. the mechanic must have tried and tried to replicate it but wasn t able to replicate the problem and, therefore, returned it to service rather than saying i know it s a serious problem and accepting that i can t find it right now, so maybe we need to bring in another aircraft and delay this flight even longer. a lot of pressure on those mechanics to get the aircraft back in service. i m not second-guessing the mechanics, but sometimes these problems are intermittent and it s difficult to identify them. when you try to replicate them, they don t happen. let me ask you about this electrical smell. what could that have been caused by in your expertise? the electrical smell is often described as electrical smell, but it s actually ozone, three milligrams of oxygen, it s o 3 ....