Genie Z135/70 mobile elevated work platform (MEWP)

Date published: 26 February 2014

Minimise the risks

HSE has reported that an operator was killed when a Genie Z135/70 mobile elevating work platform became unstable and overturned whilst it was working at or very close to its maximum height. 

In order to minimise the risks of overturn, the machine safety devices and sensors must be configured as per manufacturer’s settings, as prescribed by the manufacturer in their Safety Bulletin 130005 dated 29th July 2013. HSE recommends confirmatory checks of the calibration before platform elevation.


The purpose of this safety alert is to advise owners and users of steps to be taken to control risks associated with the Genie Z135/70 Mobile Elevated Work Platform (MEWP) following preliminary findings for a machine overturn. More information may follow in due course.

The emerging findings from the HSE investigations indicate that the operational stability of a Genie Z135/70 MEWP may be compromised by the incorrect measurement of the boom angle sensors.


In order to prevent the Z135/70 model machine operating outside its stability limits, the onboard control system monitors the elevation of the secondary boom to prevent it from telescoping outwards until its elevation is sufficient, as required by the manufacturer (greater than or equal to 75.5°).

The MEWP’s onboard control system relies on the correct setting of the elevation of each boom to maintain the effective operational stability of the machine.

Genie, the manufacturer issued a Safety Notice on 29th July 2013, which required the immediate removal of all Z135/70 MEWP’s from service until the listed inspections therein had been performed.

Action required

The manufacturer’s safety notice should be followed. Any machines for which the required calibration checks have not been completed should be removed from service. Following the completion of checks, the machines should continue to be inspected, serviced and maintained as per the manufacturer’s requirements.

Work regarding the manufacturer’s safety notice should only be carried out in accordance with the recommendations in the machine service manual i.e. on firm level ground, with suitable environmental conditions etc.

Prior to any functional checks being undertaken by an operator using the platform controls, as part of the manufacturer’s listed inspections, calibration of the angle sensors should be confirmed from ground level using an inclinometer. The use of test weights might also be appropriate.

Relevant legal provisions

  • Sections 2 & 3 of Health and Safety at Work etc Act 1974
  • Regulations 5, 6 & 20 of Provision and Use of Work Equipment Regulations 1998


More information

More information about this safety alert is available on the HSE website at the following link and Terex Genie websites.

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