The MEWP catapult effect occurs when stored energy or an impact to the MEWP’s structure causes a whiplash effect, which travels through the boom to the platform.
This situation can generate an ejection from the platform of any occupant, leading to serious injury and death, especially if occupants in boom machines are not wearing a safety harness.
When the platform is caught or snagged, it can feel to the operator that no boom movement is happening, but it may be the case that one or more wheels or outriggers are lifting clear off the ground. As and when the platform is released, wheels or outriggers return to the ground, and the stored energy or inertia creates a whiplash effect. Even a small movement at ground level could create a whiplash effect which is sufficient to eject platform occupants, tools or other materials.
The catapult effect can also occur when driving in the stowed position, so make sure occupants wear personal fall protection equipment (PFPE) that is always connected to the designated anchor point. Occupants must always use a full body harness and an adjustable restraint lanyard, adjusted as short as possible, when using MEWPs.
Key advice on the new leaflet is divided into three sections:
- Planning the job
- Evaluating the work environment while making a site risk assessment
- Checking the maintenance and guaranteeing operators are trained.
Using a spotter would help to eliminate many dangerous situations.
A spotter can identify hazards when another operator is driving the MEWP over uneven ground. Using a spotter is an inexpensive solution that can be easily implemented.
Brian Parker, IPAF’s head of safety and technical, brought his insights to LHI on the catapult effect: