Blind Lift, Radio Failure, and a Signal You Did Not Expect
A 35-ton all-terrain crane is placing a 6,500 lb air handler on a roof. To land it, the load must pass over a 20 ft parapet, after which the operator cannot see it from the cab. A rigger with a radio is on the roof; a second rigger holds a tagline on the ground. Wind is 15 mph, gusting 22, and the air handler presents about 40 ft² of sail area. Partway through the swing, with the load 30 ft up and just short of the parapet, the radio dissolves into static. At the same moment a laborer in the operator's view gives a clenched-fist signal held at chest height. The roof rigger is not visible from the cab.
1. What should have been settled before the load left the ground?
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A blind portion of a lift is a planned event, not an improvisation:
- One designated, qualified signalperson (29 CFR 1926.1428), with the operator and that person agreeing on the channel and a radio check before the pick.
- A backup method - hand signals usable wherever the operator can see the signalperson, and agreement on what happens where nobody can.
- A loss-of-communications procedure, briefed to the whole crew: stop, hold, attempt contact, and if contact is not restored promptly, land the load at a pre-identified clear drop zone on the ground that the operator can see. That zone must be cleared before the lift, not after.
- Tagline control so the load can be held from rotating without anyone standing under it.
- Access control - no one under the load or in the landing area.
- Wind plan - the manufacturer's permissible wind speed and, where the chart publishes allowable wind area for the load, confirmation that 40 ft² at this boom length is within it.
One person signals at a time. The exception is stop: anyone may give it.
2. The radio goes silent mid-lift. What do you do, step by step?
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- Stop. Brake all functions and hold the load where it is. Do not boom down, swing toward the roof, or lower on the assumption that the roof crew is ready. You are blind past the parapet, and the one thing you know for certain is that nobody is currently directing you.
- Try to re-establish control. Key up, check the channel, check that the radio is on and the battery seated. Many "failures" are a bumped channel selector.
- If contact is not restored promptly, execute the pre-briefed plan: lower the load to the clear drop zone on the ground that you can see, under control, with the tagline handler keeping it from spinning. Do not attempt the roof set blind.
- Then diagnose - swap batteries, swap radios, check for interference - before resuming. A lift stopped once can be restarted; a load landed on a crew cannot be undone.
The failure mode to avoid is treating the silence as consent. Silence means hold.
3. What does the clenched-fist signal mean, and what do the gusting winds add to your decision?
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The signal. Clenched fists held at chest height, sometimes described as "dog everything," is a stop/hold signal. It is not a question. Anyone on the site may give a stop signal and the operator must obey it regardless of who gave it - that laborer may be seeing the load brushing the parapet, a sling sliding on a corner, or a tagline handler stepping into a bad spot. Stop first, find out second.
The wind. A 15 mph wind gusting to 22 acts on 40 ft² of sail area and produces both a side load and a lagging load - the load does not stop when the swing stops. Check the manufacturer's permissible wind speed for this configuration and, where the chart states an allowable wind area, whether 40 ft² at this boom length is inside it. If it is not, the rated capacity has to be reduced or the lift postponed. Even inside the limit, the gust means slower swing, a spotter who can see the whole path, and no one under or downwind of the load.
Combined with a lost radio, the honest answer may be to land the load and wait for the wind to lay down.