Crane and Hoist Operations, Signals, and Communication
Core concepts
Safe lifting depends on a shared language and clear authority. Candidates must understand: the role of the qualified rigger and signal person, standard hand signals, voice and radio protocols, the difference between operational and emergency stop signals (anyone may give a stop), and crane dynamics - boom deflection, load swing, and the effect of hoist speed on load control. Also critical: knowing the load chart, radius measurement, and the difference between static and dynamic loading.
Traps in questions
- Believing only the signal person may stop a lift - anyone who sees a hazard may give a stop signal.
- Confusing hand signal direction (e.g., hoist vs. lower) under stress.
- Ignoring that radio failure requires a pre-planned fallback (usually hand signals or a stop).
- Assuming the operator can see the load - if not, a signal person is mandatory.
Rule of thumb
One signal person, one voice. If communication is lost, stop. Radio checks before every critical lift; hand signals as backup.
Worked example
A blind lift behind a wall: the rigger establishes radio contact, confirms channel, and agrees that loss of communication means stop and hold. The operator does not move until the signal person confirms. If the radio fails mid-lift, the operator stops and lowers only under direct visual signal or per the pre-lift plan.