What happened
On 23 August 2013, an AS3-32 L2 Super Puma, registration G-WNSB, crashed into the sea approximately 1.5 nautical miles west of Sumburgh Airport in the Shetland Islands. The aircraft, operated as a commercial passenger flight, was on approach to the airport when the accident occurred. The impact resulted in the destruction of the helicopter and caused 4 fatalities among the passengers, while the crew and remaining passengers sustained various injuries, including 3 serious injuries to passengers and 1 serious injury to the crew.
The investigation
The AAIB investigation focused on the functionality and instruction of Emergency Breathing Systems (EBS) provided to passengers during North Sea offshore operations. The investigation examined the different types of EBS in use, including compressed air, rebreather, and hybrid systems. A specific focus was placed on the Lifejacket Airpocket Plus (LAP), a hybrid system widely used in the industry. The investigators reviewed pre-flight safety briefing materials, including audio-visual DVD content and initial passenger training protocols, to determine if passengers were adequately informed about the mechanics of the equipment provided to them.
Findings
It was established that the existing pre-flight safety briefing material failed to provide a complete description of how hybrid rebreather systems operate. Specifically, the briefings did not clarify that these hybrid systems include an automatic air discharge into the rebreather bag upon submersion. This omission meant that passengers might have been under the false impression that the EBS would only be effective if they had taken a breath into the bag before entering the water. This lack of clarity regarding the automatic air supply could potentially influence a passenger's decision to utilize the equipment during an underwater emergency.
Safety action
Following the investigation, the AAIB contacted major helicopter operators serving the UK oil and gas industry. In response, these operators have committed to updating their pre-flight briefing materials. The revised instructions will explicitly state that the hybrid EBS contains its own air supply that activates automatically, ensuring the system remains usable even if the wearer has not taken an initial breath before becoming submerged.