SAFETY ALERT REF: HSSE/HSE/SA/2005-0001 TITLE: FAILURE OF HELIDECK PERIMETER NETTING DATE: 7th September 2005 UKOOA Secretariat Owner: Bob Kyle Circulation: HSE MRT, HSE, CAA, Aviation Community,

INCIDENT SUMMARY: A serious incident has occurred on an offshore installation on the UKCS, which resulted in a helideck crew member falling through the helideck perimeter netting on to a deck 20 feet below. The helideck crew member sustained a broken elbow but clearly, the potential consequences could have been far more serious.

INCIDENT CAUSE: The incident occurred because the netting failed to support the crew member’s weight. The helideck perimeter safety netting in this instance was made from polypropylene rope.

IMMEDIATE CONTROLS RECOMMENDED TO PREVENT A RECURRENCE: If you think potential exists for a similar accident to occur on your installation, the following guidelines are recommended: 1. Where practicable, prohibit personnel movement within I metre of the helideck perimeter, where it

is bounded by perimeter netting, until a serviceable condition has been verified. Where for whatever reason such a restriction is impracticable, a suitable risk assessment should be carried out before permitting access into this area (e.g. for inspection and repairs).

2. At the first opportunity, undertake a visual inspection of helideck perimeter safety nets to:

• Establish the condition and integrity of the netting and its fixings. • Check the condition of support framework and for any local damage. • Note the type and quality of construction, in particular, the netting arrangement.

FURTHER ACTIONS TO BE TAKEN AS SOON AS PRACTICABLE: 1. Repair or replacement of damaged and/or defective sections of the helideck perimeter safety net

should be scheduled at the earliest opportunity.

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2. Prior to undertaking repair or replacement it is strongly recommended that reference be made to

CAP 437 5th Edition, August 2005 Chapter 3, Section 9 and HSE Offshore Helideck Design Guidelines Section 9.10 for guidance on construction and load testing. Note: CAP 437 cautions that Polypropylene deteriorates over time whereas various wire meshes have been shown to be suitable, if properly installed. They also need to be properly maintained.

3. Where perimeter safety nets have undergone repairs / replacement in response to this Safety

Alert, the perimeter safety net must be subjected to load testing as set out in CAP 437. It should also be noted that the perimeter net testing weight in CAP 437 has recently been increased from 75kg to100 kg therefore, existing “drop test” certificates no longer meet the new requirement.

4. The CAP 437 test requirement states that the net should be strong enough to withstand and

contain, without damage, a 100 kg weight dropped from a height of 1 metre and the ideal design should produce a ‘hammock’ effect which should securely contain a body falling, rolling or jumping into it, without serious injury.

5. From a practical perspective the impact point of the test weight should be confined to as small an

area of the net assembly as possible. This is intended to simulate the “footprint” of someone stepping or jumping on to the net.

6. Prior to testing the perimeter netting a risk assessment should be undertaken and personnel

involved in this activity fully briefed on the preparation, procedure and safety precautions. During the testing process, areas beneath the test location should be quarantined and suitably protected.

OPERATIONAL CONSIDERATIONS: All installation operators, MODU and vessel owners are strongly encouraged to ensure that helideck crews obtain a better perception of the risks associated with helidecks. HLO’s should discuss the risks as a part of their daily or pre-helicopter landing “Toolbox Talks”.

OTHER INFORMATION: A copy of CAP 437 Fifth Edition 2005 can be downloaded from the CAA website www.caa.co.uk - search CAP437 or alternatively the UKOOA Extranet (Aviation Network). A copy of the HSE Offshore Helideck Design Guidelines can be downloaded from the HSE website www.hse.gov.uk/offshore/information.htm . The original information source for this Safety Alert is the Step Change - SADIE Safety Alert 819, submitted by the Installation Operator.

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