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Presentation to: The Offshore Helicopter Safety Inquiry

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Presentation on theme: "Presentation to: The Offshore Helicopter Safety Inquiry"— Presentation transcript:

1 Presentation to: The Offshore Helicopter Safety Inquiry
SRK Coleshaw Safety & Survival Consultant

2 Issues for Consideration
What personal protective equipment and clothing is necessary for helicopter passengers and pilots; What are the standards, and should the C-NLOPB require guidelines to ensure such equipment is properly fitted? Should the C-NLOPB more directly involve itself in studies and research into the prevention of inversion of ditched helicopters and enhancement of passenger’s ability to escape? What are the appropriate standards of helicopter safety training to ensure that the risk to passengers is as low as reasonably practicable, both during training and helicopter transport? Should helicopter passengers have a level of accountability for their own safety in helicopter transport?

3 Issue 1 Personal protective equipment needed by helicopter passengers and pilots Water impact: Protection from ‘cold shock’ on sudden immersion in water provided by the immersion suit. Capsize and/or submersion: Protection from drowning provided by emergency breathing systems (EBS). Following escape: Buoyancy needed to support the head above water and provide protection from breaking waves and spray. Protection from hypothermia provided by immersion suit. Location aided by personal locator beacons (PLBs).

4 Immersion suit performance
Issue 1 Immersion suit performance Protection from ‘cold shock’ by covering the skin surface, preventing a rapid decrease in skin temperature. Protection from hypothermia achieved by thermal lining and clothing worn under the suit – insulation provided by ‘trapped air’. Conflict caused by the fact that the trapped air also creates buoyancy, which makes escape from the helicopter more difficult. Level of insulation and buoyancy are both affected by the clothing worn under the suit, by the fit of the suit and the size of the suit/person. Suits are only effective when sealed – thermal stress may be a problem during flight.

5 Immersion suit standards
Issue 1 Immersion suit standards Most Relevant Standards Current Performance Requirements CGSB (1999) Helicopter passenger transportation suit systems. CAN/CGSB EASA (2006) Helicopter crew and passenger integrated immersion suits. ETSO-2C502. EASA (2006) Helicopter crew and passenger immersion suits for operations to or from helidecks located in a hostile sea area. ETSO-2C503. Levels of thermal protection: 0.75Clo / 0.5Clo Allowable leakage: 200g? Min / max levels of buoyancy: 156N min 175N / 150N max

6 Buoyancy equipment Two options: Head needs to be supported.
Issue 1 Buoyancy equipment Two options: Buoyant suit plus integral inflatable buoyancy element (oral inflation); Manually inflated lifejacket. Head needs to be supported. Wearer must be able to (at least) turn to face-up position and remain stable once in that position. Spray hood necessary to protect from wave splash.

7 Emergency breathing systems (EBS)
Issue 1 Emergency breathing systems (EBS) Time needed to escape > Breath-hold time When deployed successfully, EBS provide protection from cold shock and drowning. EBS take time to deploy, but then extend the available time underwater, to: Overcome disorientation; Release harness; Locate and jettison exit or window; Overcome any buoyancy problems? Escape from helicopter.

8 EBS performance To be effective, EBS must be: Simple in design;
Issue 1 EBS performance To be effective, EBS must be: Simple in design; Quick to deploy; Easy to use in realistic conditions: Cold water? Whilst inverted or prone in the water? Whilst escaping through exits/escape windows? Compatible with other equipment; Provide an overall safety benefit.

9 Technical standard for EBS
Issue 1 Technical standard for EBS Work is ongoing to develop a full technical standard for EBS. This will cover: Compressed air devices, rebreathers and hybrid devices; Work of breathing; Minimum deployment time (one-handed?); Performance in different body orientations; Compatibility and snagging during helicopter escape; Cold water performance; Maximum additional buoyancy. Completed standard to be submitted to EASA for possible publication as an ETSO (late 2010?)

10 Personal locator beacons
Issue 1 Personal locator beacons Provide an aid to location in addition to lights and retroreflective tape. Can be used to alert the emergency search and rescue services. Are used for homing, allowing aircraft and marine vessels to locate those in distress. PLBs used in UK sector on homing frequency

11 The Need for Helicopter Flotation Systems
Issue 2 The Need for Helicopter Flotation Systems Helicopter ditches; Limited range of stability; Upper practical limit for preventing capsize Sea State 5 or 6; Significant risk of capsize / inversion; Breaking waves present highest risk. Bell 214, Controlled ditching in calm conditions. Super Puma AS332L , Brae Alpha Controlled ditching - waves of 6-7m. Super Puma EC225, Feb Heavy landing on water (capsized some time after crew and passengers had been rescued).

12 UK CAA Research - Background
Issue 2 UK CAA Research - Background Focuses on prevention of inversion of ditched helicopters and enhancement of passengers’ ability to escape. HARP Report (1984) - identified need to improve crashworthiness and stability of helicopters. RHOSS (1995) – emphasised importance of helicopter flotation systems and the need for helicopters to stay afloat long enough for survivors to escape. Discussed possibility of additional flotation to cater for a crash. EBS Workshop (2000) – recognition of mismatch between time needed to escape from an inverted helicopter and realistic breath-hold times in cold water.

13 UK CAA Research - Stability
Issue 2 UK CAA Research - Stability Sea anchors: Can help the helicopter to turn head in to the wave, but difficult to deploy and take too much time to be effective. ‘Wet floor’ approach: Helicopter sits lower in the water – variable results. Float scoops: Improved stability, mainly due to roll damping. Increase capsize threshold by 1 sea state.

14 CAA Research – Prevention of inversion (BMT Fluid Mechanics Ltd, 1997)
Issue 2 CAA Research – Prevention of inversion (BMT Fluid Mechanics Ltd, 1997) Model study investigating novel flotation systems. One set of exits above water and air gap in cabin. Combination of buoyant engine cowling and long flotation bag prevented double rotation, and was stable in waves. Additional flotation, high up.

15 Escape from above-water exit
Issue 2 CAA Research Human factors (RGIT Ltd, 2001) Escape from a side-floating helicopter after rotation of 150˚ was compared to escape from a fully inverted helicopter. Air gap in cabin Escape from above-water exit

16 CAA Research – Human factors
Issue 2 CAA Research – Human factors Submersion time (breath-hold time): 9.5s in side-floating cross-cabin escape; 20s in underwater cross-cabin escape. 89% found cross-cabin underwater escape to be ‘moderately’ or ‘very’ difficult. Only 29% of subjects rated the equivalent exercise in the side-floating escape to be ‘moderately’ or ‘very’ difficult. Escape from a side-floating helicopter was easier than escape from a fully inverted helicopter, and was preferred by 90% of subjects.

17 Issue 2 EASA Research – Type-specific design study (Eurocopter & Aerazur, 2009) Design objectives for an additional emergency flotation system considered for both a light (AS355) and heavy (EC225) helicopter. Model of EC225 model studied in waves . Symmetric design with buoyant cowling panel plus flotation bags on both sides of upper cabin was most effective with respect to stability in waves and number of windows above water. Better buoyancy redundancy with this design if one standard (lower) buoyancy bag damaged.

18 Crashworthiness Research
Issue 2 Crashworthiness Research Clifford (1996) – drowning is major cause of death in helicopter water impacts, particularly with vertical descents with limited control and fly-in accidents. Impact injuries predominate in uncontrolled impacts and non- survivable accidents. WS Atkins (2001) – recommended design modifications to improve crashworthiness of flotation systems, including automatic arming and deployment. BMT (2001) – studied effects of impact and recommended additional floats high on the cabin wall where they will be protected from all but side impacts.

19 CAA Research – Emergency breathing systems (SRK Coleshaw)
Issue 2 CAA Research – Emergency breathing systems (SRK Coleshaw) Initial study (2003): Reviewed extent of knowledge on various EBS designs. Satisfactory performance of EBS considered to depend on good design, reliability of equipment, ease of use and level of training. Development of Technical Standard ( ): Cool and cold water performance trials on three generic designs; Development of full technical standard, to be put out for consultation prior to publication.

20 CAA/EASA Research - Overview
Issue 2 CAA/EASA Research - Overview The side-floating scheme is considered to present the optimum solution to the current problems with inversion. The UK CAA have stated that they are not aware of any insurmountable problems that would render the side- floating scheme impractical or ineffective at least for new build/design helicopters. EBS provide a short–term solution for post capsize survival pending availability of the side-floating scheme. They may provide a degree of long-term mitigation if additional flotation proves impractical to retrofit. EASA proposes to establish a workshop in 2011 to review all of the helicopter ditching and water impact requirements, advisory material and research.

21 Helicopter Safety Training - Value
Issue 3 Helicopter Safety Training - Value Evidence that survival rates are higher for those who have received helicopter underwater escape training (HUET). Training should provide information about what to expect, practical training in the procedures that must be undertaken, and allow individuals to build coping strategies that will reduce panic in the emergency situation. In real emergencies a number of behaviours are seen: Fear/anxiety; Disorientation; Depersonalisation; Panic; Inaction / ‘freezing’. Training should aim to reduce the likelihood of such behaviours.

22 Helicopter Safety Training - Issues
Fidelity of training: Simulator / seats / harness / exits? Training frequency; Stress / anxiety caused by training.

23 Issue 3 Training Standards Training needs to cover evacuation, underwater escape scenarios and use of EBS where appropriate. Training standards are laid down by organisations such as OPITO. OPITO course covers dry evacuation / underwater escape without and with EBS / escape without and with windows / submersion and capsize. Some differences in standards relating to the level of realism created.

24 Personal Accountability for Safety
Issue 4 Personal Accountability for Safety Confidence in water / swimming ability? Clothing worn under helicopter immersion suits? Correct sizing and fit of helicopter immersion suits? Attitude to training? Personal survival strategy for helicopter transport? Responsibility for speaking out?

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