How many hours a day does a Mechanical Engineer work?

Being a salaried employee a Mechanical Engineer only gets paid for 8 hours of work a day, no matter how many hours he actually works.

While in most cases he does only work 8 hours in a day, when schedules are slipping or other problems crop up he will be expected to work as much as necessary to resolve it as soon as possible. I have known a few engineers that worked more than 20 hours a day for a few weeks to resolve a particularly difficult issue.