What condition prevents an operator from applying power to a hoist or other powered lifting device?

The presence of an AF Form 979 attached to the unit indicates that the device is not currently authorized for use. This form typically signifies that there are maintenance issues, safety concerns, or that the hoist has been taken out of service for inspection or repair. Therefore, it is a clear signal to operators that they must refrain from applying power to the hoist or any powered lifting device.

In contrast, while missing a safety inspection report or having an untrained operator may suggest potential issues, they do not explicitly prevent the application of power. Similarly, while a lifting device not being calibrated indicates a potential risk, it does not necessarily mean that it is grounded or prohibited from use unless specifically indicated by a safety form like the AF Form 979. Thus, the most effective way to ensure safety and compliance is to adhere to the directive represented by the AF Form 979.