Signaling and Communication
Signaling and Communication
This domain tests how the lift is directed when the operator cannot see the load or the landing area. The exam stresses one clear signal authority, standard hand signals, radio protocol, and the requirement to stop when communication is lost.
Core rules
- Use one designated signal person for the lift. If a relay is necessary, each relay must clearly understand and pass the same signal.
- Hand signals must be the standard signals used for mobile cranes; do not invent local signals during a lift.
- The operator must stop if the signal is unclear, the signal person is out of sight, or radio communication fails. Resume only after clear communication is restored.
- Anyone may give an emergency stop signal. This is the exception to single signal authority.
- Use a pre-lift discussion to confirm radio channel, hand signal method, blind spots, and the stop signal.
- For a blind lift, position the signal person where the load, landing area, and crane swing path can be observed, or use a qualified relay.
Worked example
A signal person is directing a pick around a wall. As the load clears the wall, the signal person steps back and loses sight of the landing area; at the same time the radio goes silent. The operator should stop and hold the load, not continue on assumed hand signals from a worker near the landing point. The reasoning: without a clear signal from the designated authority, the operator cannot verify clearance or load position. The lift resumes only after the signal person regains sight or a qualified relay is established and communication is tested.
Traps
Accepting signals from two people at once; treating a radio as a substitute for a qualified signal person; continuing after a garbled transmission; and forgetting that emergency stop is open to anyone.