Peter Gibbs l President of Survival Systems Training Limited, Dartmouth, NS. l Designed course curriculum for Emergency Breathing Systems for both military.

Peter GibbsPeter 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. email me at [email protected]

Foster broader knowledge and understanding of the differences between a compressed air breathing system and a rebreathing systems used for helicopter underwater escape.

The Principles of Emergency Breathing The Principles of Emergency Breathing Systems for Helicopter Underwater EscapeSystems for Helicopter Underwater Escape

Helicopter Statistics*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).

Why People PerishWhy 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.

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

The StudyThe 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 23-92 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)

The SolutionThe SolutionProvide some form of air system (3 systems)

Compressed Air

Based on Self Contained Underwater Breathing Apparatus (SCUBA)

Rebreather

Based on breathing air at atmospheric pressure

Hybrid Rebreather

Based on breathing air at atmospheric pressure plus 3.5 litres of compressed air

Provide some form of air system (3 systems)

Types of SystemsTypes of Systems

Compressed Air

Demand Valve

Mouth Piece 1st Stage Regulator

Aluminum Cylinder 3000 psi

Low Pressure Hose

Types of SystemsTypes of Systems

Rebreather

Securing Strap

Red Activating Knob

Mouth Piece and Nose Clip

Flexible Hose

Counter Lung

Types of SystemsTypes of Systems

Hybrid Rebreather

3.5 Litres Compressed Air

Emergency Manual Inflator

Salt Water Activated Automatic Inflator

Securing Strap

Systems SpecificationsSystems Specifications

COMPRESSED AIR Working pressure 1800 lbs psi -

3400 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 +

3.5 litres System weight - 2.25 lbs. Regulator - not required Demand valve - not

required Duration - ?

Compressed AirCompressed Air

POSITIVE Instant supply of air

underwater. Requires no prior activation

Duration 2 - 6 minutes Several types available Purge capability Proven in real accidents

NEGATIVE Pulmonary over inflation

injury Integration difficulties with

survival equipment Runs out without warning

Rebreather (Hybrid)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

IntegrationIntegration

Many Different Systems

Lifejacket Suit Mounted in Aircraft

Requires skillful human engineering to match air system to equipment and aviation environment

Flight Commander Leg Mounted Flight Commander Leg Mounted Compressed Air SystemCompressed Air System

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

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

Leg Mounted Compressed Air System Using a Helly Leg Mounted Compressed Air System Using a Helly Hansen Immersion SuitHansen Immersion Suit

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

Hybrid Rebreather Using a 4-Point HarnessHybrid Rebreather Using a 4-Point Harness

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

Training RequirementsTraining Requirements

All Systems Require:

Theory Training Practical Wet Training Practical Underwater Egress Training Approximately four (4) hours

MaintenanceMaintenance

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)

ConclusionConclusion 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