What is the greatest stability angle for an aerial device extended away from its line?

The greatest stability angle for an aerial device extended away from its line is 60 degrees. This angle is critical for maintaining the balance and stability of the aerial device while it is in operation. At 60 degrees, the device can safely handle the load and dynamic forces that may act upon it, such as wind or the weight of personnel interacting with the platform.

An angle greater than 60 degrees puts the device at risk of tipping or becoming unstable, as the center of gravity moves outside of its base of support. Similarly, while angles of 45 degrees or lower can provide stability, they do not maximize the effective reach and performance capabilities of the aerial ladder. At 90 degrees, the ladder would be positioned vertically, significantly reducing its usability for most operational scenarios, as it can only support vertical movements rather than reaching outwards effectively. Thus, 60 degrees strikes the optimal balance between stability and reach for an aerial device.