xliioper

Not sure what delays (mechanical or otherwise) have to do with IDB's? A delayed/canceled flight does not constitute an IDB if that is what you are asking. It's only when you have meant all the requirements for checking-in and being at the gate on time with a confirmed reservation on the flight, and the flight actually departs without you due to not enough seats available. There is an out of they have to do a last minute equipment substitution for a smaller aircraft due to operational/safety issues. As well as for aircraft with less than 60 seats due to weight and balance issues.

I was on an NW DC-9 flight from DTW-JFK a number of years ago where they had to offload 4 pax for weight issues due to high heat/humidity. Since the DC-9 holds over 60 pax, it would have been an IDB situation if the could not find enough volunteers. Initially they were only asking for people without international connections to volunteer. When they couldn't get enough volunteers, they opened it up to pax with international connections as well. I was flying DTW-JFK-AMS, so I took a voucher and was able to get on a non-stop DTW-AMS flight that arrived earlier. In the end, they didn't need to IDB anyone and there was no drama involved.