1. Peter Gibbs
President of Survival Systems Training Limited, Dartmouth, NS.
Designed course curriculum for Emergency Breathing Systems for both military and civilian helicopter operations.
Provided train-the-trainer programs in Aircraft Ditching and Emergency Breathing Systems world-wide for both military and commercial operations.
22 years service in the Royal Navy as a helicopter search and rescue diver and commando helicopter crewman.
Commercial divers certificate HSE Part IV (UK), Master Sports Diver ACUC.
31 years in the survival business.
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ENSURE THAT THE TRAINEES UNDERSTAND THE RELATIONSHIP BETWEEN ALL THREE COMPONENTS.

2. The Principles of Emergency Breathing Systems for Helicopter Underwater Escape
Foster broader knowledge and understanding of the differences between a compressed air breathing system and a rebreathing systems used for helicopter underwater escape.

3. Helicopter Statistics*
In 24 accidents where the cause of death was known
162 fatalities
92 drowned
56.7% of fatalities were the result of drowning (where the cause of death was known).
*World Civil Helicopter Water Impacts: Summary of Occupant Injuries. Courtesy Clifford (1996).

4. Why People Perish
Survival will be determined by an individuals’ breath-hold time.
Cold shock (Essentials of Sea Survival, Golden and Tipton).
Gasp reflex and inability to breath hold.

5. A Histogram of BHT Under Water in 228 Subjects (Cheung et al, 2001)

6. The Study
Scientific Study. An Investigation of Passenger Evacuation from the Super Puma Helicopter. Brooks, Muir, Gibbs. (March 1999).
All participants were underwater escape trainers or divers and each person carried an emergency breathing system for added safety.
Study showed under controlled conditions there was a breath-hold requirement of between seconds for all subjects to escape.
This study proved that there was a need for passengers to carry some form of supplementary air. (Published June 2001, Aerospace Medical Journal)

8. The Solution Provide some form of air system (3 systems)
Rebreather
Hybrid Rebreather
Compressed Air
Based on Self Contained Underwater Breathing Apparatus (SCUBA)
Based on breathing air at atmospheric pressure
Based on breathing air at atmospheric pressure plus 3.5 litres of compressed air

9. Types of Systems Compressed Air Demand Valve 1st Stage Regulator
Mouth Piece
Aluminum Cylinder 3000 psi
Low Pressure Hose

10. Types of Systems Rebreather Securing Strap Mouth Piece and Nose Clip
Flexible Hose
Red Activating Knob
Counter Lung

11. Types of Systems Hybrid Rebreather Emergency Manual Inflator
3.5 Litres Compressed Air
Salt Water Activated Automatic Inflator
Securing Strap

12. Systems Specifications
COMPRESSED AIR
Working pressure 1800 lbs psi lbs
Volume 42 litres - 80 litres
System weight - approximately 3 lbs.
Regulator - first stage
Demand valve - second stage
Duration of air supply approximately 21 breaths at 21 feet*
*based on an average breath volume of 1.5 litres at a breath rate 10.5 bmp with a starting pressure of 3000 psi.
REBREATHER/HYBRID
Atmospheric pressure
Volume = Lung volume litres
System weight lbs.
Regulator - not required
Demand valve - not required
Duration - ?

13. Compressed Air POSITIVE
Instant supply of air underwater. Requires no prior activation
Duration minutes
Several types available
Purge capability
Proven in real accidents
NEGATIVE
Pulmonary over inflation injury
Integration difficulties with survival equipment
Runs out without warning

14. Rebreather (Hybrid) POSITIVE Simple design NEGATIVE
Complex procedures to follow to make operational during critical part of flight (I.e. ditching)
Must activate the system before immersion.
No purge capability (cannot be operated under water)
Breathing resistance changes with orientation and depth. May be difficult or impossible to breathe at depth.
Requires a full breath of air prior to going underwater (rebreather only)
Danger of Hypoxia
Hybrid Pulmonary Over inflation injury
Integration difficulties with survival equipment
POSITIVE
Simple design

15. Many Different Systems
Integration
Many Different Systems
Lifejacket
Suit
Mounted in Aircraft
Requires skillful human engineering to match air system to equipment and aviation environment

16. Flight Commander Leg Mounted Compressed Air System

17. Brace Position Leg Mounted Compressed Air System (2 point harness)

18. Compressed Air System Lifejacket/Chest Mounted Using a 4-Point Harness

19. Leg Mounted Compressed Air System Using a Helly Hansen Immersion Suit

20. Lifejacket/Chest Mounted Compressed Air System Using a 4-Point Harness

21. Hybrid Rebreather Using a 4-Point Harness

22. Hybrid Rebreather Deployed and Ready for Use (Breathing Atmosphere)

24. Training Requirements
All Systems Require:
Theory Training
Practical Wet Training
Practical Underwater Egress Training
Approximately four (4) hours

25. Maintenance Compressed Air System User visual check Recharge
2 year check cylinder and replace O-rings
5 year hydrostatic test if cylinder is greater than 2” in diameter.
Hygiene easy
Rebreather
User visual check
Re-pack
5 year replace gas cylinder, operating mechanism, O-rings and swivel elbow
Hygiene difficult and time consuming (training only)

26. Conclusion
It is vital to have some form of air system for helicopter underwater escape, especially flying over water below 150C
I have discussed the advantages and disadvantages of three systems - compressed air, a rebreather (with no compressed air) and a hybrid rebreather (with compressed air).
It is important that the correct system is implemented and that thorough human engineering has been used to integrate the system so it works as advertised.
Questions