100 Hour Wing Inspection

[Ernie Martin]

All/most of what you're asking is covered in the SID thread, such as the history of SIDs, and I strongly urge you to read the whole thread. There are a lot of 337s used commercially, for forest fire surveillance and forward air control, for military surveillance (AirScan operates 23 of them, mostly overseas), and for wildlife/fisheries surveillance. So it's better to say Part 91 rather than "in general".

Ernie