A common mistake I see in aerospace value streams is in the lead time ladder calculation. The lead time ladder has of course the inventory queuing component and the process time. When adding up the lead times, I often see people just adding up the top line of the ladder (queue time) and ignoring the process time. In automotive, I see queue times of like 2 days with process times of 30 seconds; then of course it wouldn't matter much if you didn't add the process time in your lead time calculation. But at my aerospace company, I often see process times of like 4 days and queue times of 20 days. In that case, if you didn't add the process time to your queue time to get your lead time, you would think your getting a part out in 20 days instead of 24.