Helicopter Underwater Escape #2

The research objectives and expected outcome

This research project addresses the safety recommendation (SR) 2016-016 from the UK Air Accident Investigation Branch (UK AAIB) report AAR 1/2016 on the accident of helicopter G-WNSB on 23 August 2013: “It is recommended that the European Aviation Safety Agency instigates a research programme to provide realistic data to better support regulations relating to evacuation and survivability of occupants in commercial helicopters operating offshore. This programme should better quantify the characteristics of helicopter underwater evacuation and include conditions representative of actual offshore operations and passenger demographics.”

An initial review into the nature of the research was commissioned by EASA in 2020. The results of the first  Helicopter Underwater Escape research project provided a comprehensive review of currently available information on underwater escape, identified shortfalls, and recommended further work to rectify this lack of information. 

Two of the highest-priority recommendations identified in the previous project will be addressed by this research project, namely forces required to jettison push-out underwater emergency exits and underwater escape from the passenger cabin with a full complement of passengers.

This action will provide information to assist future rulemaking activities aimed at improving the likelihood of a successful escape in survivable helicopter water impact accidents. Said rulemaking activities could potentially lead to proposed amendments to the Certification Specifications for Rotorcraft (CS-27 and CS-29), Air Operations Rules for helicopter offshore operations (HOFO) and additional airworthiness specifications (Part 26 and CS 26), and all the associated AMC and guidance material (GM). 

The output will also provide valuable technical information to support the development of the eVTOL and urban air mobility rules, requirements and means of compliance material to enhance survivability of occupants following accidents during overwater operations.

The requested output

The following activities should be addressed under this project, to:

  • Evaluate the influence of being underwater on the required jettison force and operation of an underwater emergency exit or escape window.
  • Determine the forces that human test subjects (covering the range of sizes from 5th percentile female to 95th percentile male) are capable of applying to jettison an underwater emergency exit or escape windows when underwater.
  • Establish an appropriate maximum operating/jettison force for underwater emergency exits to ensure that these exits are operable in an emergency when underwater.
  • Provide confirmation of the validity of the current CS-27 and CS-29 AMC material for compliance with the requirement ‘the means of opening each emergency exit must be simple and obvious and may not require exceptional effort’ for underwater emergency exits, or propose a future revision based on the technical findings of this research.
  • Better quantify the underwater escape process from a capsized helicopter using a full complement of test subjects in the simulator, in both light and dark conditions. 
  • Determine whether the current expectation of a 60-second escape time is achievable under a range of conditions and possible seat configurations, using test subjects representative of the demographic of the European offshore population.
  • Validate the current CS-27 and CS-29 requirements and AMC material related to occupant egress in the event of a capsize, or propose a future revision based on the technical findings of this research.

The project is structured along the following tasks:

  • Task 1:  Jettison of push-out underwater emergency exits
  • Task 2:  Underwater escape from the passenger cabin with a full complement of passengers
  • Task 3:  Communication, dissemination, knowledge-sharing, stakeholder management
  • Task 4:  Project management of the task