With all of the weight that's in the base of telescopic- and articulating-boom aerial-work platforms, the only safe point to secure them is at the tie-down lugs.
- Make sure the boom's turntable is locked before transporting (and don't forget to take the locking pin out before putting the machine back into operation).
- If the slope of the transport's ramp or bed is steeper than the machine's slope rating, winch the unit on and off the truck bed.
- Only winch or tow a boom by hooking to the tie-down lugs.
- Use a minimum of four chains of ample load capacity on the tie-down lugs.
- Secure the platform. Make sure it is in the stowed position and run a nylon strap over the platform mount. Don't pull down with excessive down force.
Read a discussion of equipment tie-down procedures at HeavyEquipmentForums.com