Shared Channel, Dead Battery
Refinery turnaround. You are the signalperson for a 90-ton rough-terrain crane working a pipe rack. All radios on site share one channel with two other cranes and a truck driver. The operator's view of the set point is blocked by the rack, so voice signals are primary. Your first transmission is a bare 'hoist' with no crane identified; a different crane's operator hoists and nearly two-blocks his block. Ten minutes later, mid-lift with a 6,000 lb valve 15 ft in the air over the rack and drifting, your radio battery dies. You are behind the rack, out of the operator's sight. An ironworker on the rack starts hand-signaling the operator to lower, and the truck driver keys up to say 'clear.'
1. What should the first transmission have been, and what radio discipline prevents the wrong crane from responding?
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The first transmission should have named the crane and the function: 'RT-90, hoist,' followed by the operator repeating back 'RT-90, hoisting' before anything moves.
Discipline that prevents the failure seen here:
- Identify the crane on every transmission. Never a bare verb. 'Hoist' is a command to every crane on the channel.
- Positive acknowledgement on the first move of a pick. Repeat-back catches both misidentification and mishearing.
- Dedicated channel per crane where the site allows it. If it doesn't, crane-specific call signs are mandatory, not optional.
- One designated signalperson per crane at a time, with hand-offs announced: 'RT-90, signalperson change, hold.'
- A reserved stop phrase (e.g. 'ALL STOP') used only for stopping and obeyed by everyone on the channel.
- Test the system before the lift and treat radio quality as part of the lift plan, per the requirements for electronic signal transmission.
The near-miss here was not an operator error; it was a control-system error. Fix the protocol, not the person.
2. Your battery dies with the valve 15 ft in the air over the rack. Describe what happens next - the operator's action, your action, and how this should have been planned.
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The operator: on loss of communication he stops the motion and holds. He does not lower, swing, or boom on the assumption that it is what you would have wanted. A brief suspended hold is acceptable; leaving a suspended load unattended is not.
You: do not walk under the load to regain line of sight. Move to a position where the operator can see you and take over with hand signals, or use a pre-arranged backup - spare battery, second radio, air horn, or a rigger with a working radio relaying your instruction. The goal is to land the valve at a planned location, not to finish the original set.
Prevention (the real answer):
- Spare battery on the harness and a radio check at shift start.
- An agreed hand-signal fallback and a agreed lost-communication rule briefed before the first pick.
- A load path that keeps you in sight of the operator for most of the lift, so a radio failure degrades to hand signals instead of to nothing.
Judgement point: the dangerous instinct is to fix the radio while the load hangs. Re-establish control first, then troubleshoot.
3. The ironworker hand-signals 'lower' and the truck driver calls 'clear.' Who does the operator obey, and what do you do about each?
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The ironworker's 'lower': no. Operational signals come only from the designated signalperson for that crane. The operator should not act on a swing, hoist, or lower command from an unauthorized person, and the lift should stop long enough to shut that down - it is a control problem, not a personality problem. Handle it at the pre-lift meeting and again in the moment: state who signals this crane, and that anyone may stop it.
Any stop or emergency stop from anyone: yes, immediately, including from the ironworker or the truck driver. A stop is a safety valve, not a transfer of control. The operator does not screen it for credentials.
The truck driver's 'clear': meaningless without identification - clear for which crane, which load, which direction? A bare 'clear' on a shared channel is the same defect as a bare 'hoist.'
What you do: reassert control, put the lift on hold, confirm the channel is clear of non-essential traffic, restart with identified transmissions, and if the ironworker is genuinely needed as a signalperson at the set point, designate him formally and confirm his qualification before he takes over.