Emergency lowering is a secondary way to bring an aerial work platform back to ground level when the normal controls cannot be used. On a scissor lift this typically means opening a valve so the deck sinks straight down. On a boom lift the task is harder: the platform can sit several metres out from the chassis, above obstacles, so the boom sections must be folded and lowered in a controlled sequence rather than dropped. The system uses either auxiliary power that drives functions slowly, or manual valves that let sections descend under gravity — and in both cases a trained person on the ground, not the stranded operator, usually carries out the procedure.

Why does a platform get stuck at height in the first place?

Typical triggers for an emergency lowering situation include loss of main power, a flat battery, a hydraulic or control fault, an operator who becomes ill or injured, or entrapment of the operator against a structure. None of these are rare edge cases reserved for extreme conditions — they are the standard list of failure modes any aerial work platform fleet manager has to plan around. The common thread is that in every scenario, the people on the ground need a procedure they have already rehearsed, not one they improvise under pressure.

Two systems, one goal: controlled descent

  • Auxiliary power: a backup power source that runs the machine's functions slowly, allowing a near-normal lowering sequence.
  • Manual lowering valves: valves that release boom sections so they descend under gravity, following a model-specific order.
  • Ground control station: the usual point from which the emergency system is operated, though some machines also allow it from the platform.

Is the emergency stop button the same as emergency lowering?

No — and confusing the two is a documented hazard. The red emergency stop buttons at the platform and at the ground controls simply cut power to the machine's functions. They stop movement; they do not bring the platform down. The lowering system is a separate function, typically operated from the ground control station or the chassis. Before any job starts, the ground crew needs to know the location of the ground controls, the key and selector switch, the auxiliary power switch, and any manual lowering valves, as well as the order in which boom sections must come down and the duty-cycle limits of the auxiliary pump.

Who is allowed to operate the emergency descent system?

Only people trained and familiarised on that specific machine's emergency procedure, and named in the site's rescue plan, should touch the controls. In practice that means the operator and at least one ground person who remains on site for the duration of the lift. Untrained bystanders should not attempt to operate the system, and emergency services called to the scene may not be familiar with that particular model — which is why a rescue plan cannot rely on outside responders as the sole fallback.

What belongs in a rescue plan?

  • Written procedure: drawn up before work starts, defining who responds and which method brings the platform down.
  • Dedicated ground person: trained on the exact model, present on site, able to reach the controls quickly.
  • Clear access: the ground control station kept free of materials and vehicles, with the key stored in a known location.
  • Lowering path check: structures, cables, branches, people and vehicles the platform will pass on the way down.
  • Entrapment response: a defined first movement to reverse if the operator is pinned against a structure.
  • Post-incident steps: taking the machine out of service, reporting the event, and having it inspected before reuse.

Because sequences, valve locations and operating limits differ from one model to the next, the operator's manual for the specific machine always takes precedence over any general guidance. The same applies to scissor-lift style equipment such as the scissor platform, where the lowering logic is simpler but still machine-specific.

What this means for fleet operators

Emergency lowering competence sits alongside other operator qualifications that fleet managers already track through maintenance intervals and machine familiarisation records — it is not a one-off certificate but a skill that needs rehearsal on the actual model in use. Operators moving between different boom lift types should expect to repeat the familiarisation step each time, since valve positions and lowering sequences are not standardised across manufacturers. For fleets running mixed equipment, building emergency-lowering drills into routine site inductions is the most direct way to turn a documented rescue plan into something crews can execute without hesitation when it actually matters.