24-Jan-2014 Source: AAIB
OThe AAIB has issued a Special Bulletin specifically referring to the CHC AS332L2 fatal accident of G-WNSB near Sumburgh on 23 August 2013. The key information from this bulletin is shown below, but it is best taken in context of their full report.
This Special Bulletin is published to highlight a safety concern relating to pre-flight safety briefings, given to passengers, on the functionality of emergency equipment provided to them for UK North Sea offshore helicopter flights.
Research has identified that in about 60% of all helicopter water impacts, the helicopter inverted or sank, immediately or after a short delay. A capsize often occurred before evacuation of the occupants could be completed. As a result, Emergency Breathing Systems (EBS) were developed to allow helicopter occupants to breathe underwater for a short period of time. The EBS can bridge the gap between the maximum breath-hold time of an occupant and the time required to complete an underwater escape, thereby increasing the chances of survival. EBS were introduced in UK North Sea offshore helicopter operations as a voluntary industry standard; at present there is no regulatory requirement for such equipment.
The pre-flight safety briefing material has been reviewed by the AAIB as part of its ongoing investigation. This has identified that the briefing material does not include fully representative information about the EBS. It does not highlight that the EBS provided may be a hybrid rebreather containing an air supply which is discharged automatically into the rebreather bag, or that the system can be used even if the wearer has not taken a breath before becoming submerged.
Incomplete information in the pre-flight safety briefing material may give passengers the false impression that hybrid rebreathers such as the widely used LAP system are only of benefit if the user has taken a breath prior to becoming submerged. Knowledge that hybrid rebreathers contain their own supply of air may therefore influence a passenger’s decision on whether or not to use the EBS in an emergency situation.