Article #1

SERVICE REQUIREMENTS FOR SAFETY EQUIPMENT

Fire extinguishers, Life vests and Life rafts are generally some of the least thought about items on an Aircraft.......until you need them. At that point, these key items, if properly serviced and maintained, can save your life.

When we think about aircraft maintenance we tend to put a lot of stock into major components such as engines, instrumentations and structural integrity, to name just a few. While these and numerous other items are critical to flight safety, it is the safety accessories that will allow survival of crew and passengers in the event of a catastrophic failure of any of these crucial components.

Let's look first at fire extinguishers. All extinguishers must be of a suitable size and type to extinguish a typical fire that may be encountered within the aircraft. Extinguishers vary in size and type, however, it is generally accepted that Halon is the fire- fighting agent of choice.

Much has been said in regards to Halon. Yes, if used on a fire in extremely confined spaces toxicity can be a factor, however, these levels are relatively minor in comparison to the toxicity of the fire itself.

Yes, Halon production in North America has ceased due to the signing of the Montreal Protocol. The banning of the manufacture of this agent was required due to the fact that Halon's contain C.F.C.'s(Chlorofluorocarbons).

These C.F.C.'s have been attributed to the reduction of the ozone layer. As a result of this finding, all commercial, industrial and residential use of this agent has been banned.  The exemption, to the banning of Halons, has been granted to allow use of Halon on-board aircraft and military tactical vehicles only.

Industry and manufacturers have been working diligently to find a suitable replacement for these extinguishers, however no substitute has been developed that is as effective at combating cabin fires while inflicting the least amount of damage to critical electronic components.

Halon, which is a colourless, odorless liquid, works to extinguish a fire by surrounding and attaching itself to oxygen molecules, thus not allowing the O2 to fuel the fire. The benefit of this method of attacking the fire, is that while oxygen is deprived from the fire, it still allows the digestion of oxygen to crew and passenger through the molecular attachment of Halon.

Alternatively, carbon dioxide (CO2) would be impractical due to weight and the fact that CO2 actually eliminates all oxygen from the fire completely, thus creating a suffocation environment.

Dry chemical powder is also impractical for cabin fire safety. While Dry chemical is effective in combating fires, the corrosive nature and fine particulants that are emitted on discharge, would destroy sensitive electrical equipment and make sightlines impossible for the pilot.

So, we are back to Halon, where the benefits out-weight the draw- backs.

There are numerous Halon Banks in North America that allow the purchase of Mil. Spec. agent by Aircraft Maintenance Organizations. As such, it would be decades before this agent becomes un-available. All AMO's that service Halon extinguishers, are required to have ULC approved Halon re-capture and recovery equipment that is 99.9% efficient.

Extinguishers are to be inspected as follows:

Annual Inspection

• External examination, checking for dents, corrosion etc..

• Leak detection

• Weight inspection

• Hose/Nozzle blockage

• Ensure safety pins and tamper seals are intact

• Issuance of Maintenance Release

Six Year Maintenance

• External examination (as above)

• Recovery of Halon

• Internal shell examination

• Lubrication of O-rings and valve stem

• Application of "verification of service" collar

• Re-fill of appropriate quantity of agent

• Apply new tamper seals

• Leak detection

• Issuance of Maintenance Release

12 Year Hydrostatic Test

• External examination (as above)

• Recovery of Halon

• Internal shell examination

• Pressure test of shell (integrity)

• Replacement/Lubrication of O-rings and Valve stem

• Service Collar

• Refill of agent

• Tamper seals

• Leak detection

• Maintenance release

In the event that the unit becomes un-serviceable, new Halon extinguishers can be purchased for use on-board aircraft from an Approved Maintenance Organization specializing in Fire safety equipment.

Another type of fire extinguisher commonly used on board aircraft are "Fire Bottles" These are fixed fire extinguishment systems, protecting engines. The agent used in these systems, are again, Halon.  As described above, there is no other agent as effective and practical in combating these type fires.

The two most widely used fire bottles are manufactured by HTL/Pacific Scientific and Walter Kidde Aerospace.

Kidde and HTL bottles also must be regularly maintained. Annual inspection/certification must be conducted on these units, similar in effect, to the same standards as a portable extinguisher.

Fire Bottles, are required by the manufacturer, to be "Overhauled" at Five (5) year intervals, this consists of the following:

• Removal of Squibs (explosive cartridges)

• Recovery of Halon

• Removal of decals and paint

• External examination of bottle

• Tear down and evaluation of hard parts

• Internal examination of bottle

• Pressure test of bottle (integrity)

• Replacement of all soft parts i.e.: O-rings/Seals/Gaskets

• Replacement of hard parts where and when required

• Lubrication of O-rings, seals and gaskets

• Re-assembly of components

• Refill with Mil. Spec. Halon

• Leak detection

• Issuance of Maintenance Release

Note: As these bottles use explosive cartridges/squibs to activate discharge, care and attention must be given to the "life" of these ordinances.

Most commonly these cartridges have up to a Six (6) year shelf life and Four (4) year in service life subsequently, they must be removed/replaced at the appropriate interval.

These fire safety items are items that are there for a reason, they may not be on the for front of the minds of maintenance personnel, however, when they are needed they must work. Safety of life depends on it.

The first element to survival when there is an aircraft failure in an over water situation is whether or not the pilot and crew are trained on how to maneuver the aircraft into water safely, thus allowing the ditching to occur without the destruction of the aircraft.

Following that training and of equal importance is the training of passengers and crew on donning and use of the Personal Flotation Devices (P.F.D.)

PFD's range in variety, from flotation cushions to Life Jackets.

Life Jackets must be approved by Technical Standard Orders (TSO) and be designed so that if the passenger donning the jacket is knocked unconscious by ditching or by injuries sustained by egress from the aircraft, a crew member, or other passenger, can inflate the life jacket and the passenger will be kept afloat with no effort on their part.

Life Jackets are required to be inspected/maintained at intervals consistent with manufacturer's recommendations, the authority having jurisdiction and with Aircraft Maintenance Organizations (AMO's) maintenance policy manual.

The average maintenance requirement for life jackets are two (2) years from new and once annually after that. Some manufacturers have extended service requirements to, in some cases, five (5) years.  This would be the exception to the rule.

It may seem unlikely that if a life jacket has not been used that there would be a reason to have it inspected, however, depending on handling, transfer and on-board stowage there is a chance that even sealed, the unit may become punctured, torn or otherwise damaged.

Therefore, it is highly recommended that annual maintenance be conducted. This service is relatively inexpensive and provides both operator and passenger the level of safety assurance one would expect.

Lifejackets (PFD's) are to be inspected as follows:

• Preliminary visual external examination

• Functional test and reliability

• CO2 inflation cylinder weight check

• Leakage test

• Determination for need of repair or overhaul

• Issuance of Maintenance Release Certificate

The Preliminary Inspection consists of Inspecting all fabric for abrasion, chafing and soiling. The stitching and webbing is to be carefully examined to ensure integrity and the oral inflators to be checked for signs of corrosion or damage. All buckles, also need to be checked to ensure they operate correctly as do the water activated batteries and light assemblies.

It is recommended that a minimum of one (1) flotation vest per lot of 30 (or less) be functionally operated to ensure correct operation of unit as designed by manufacturer.

The weight check on the CO2 cylinder consists of removing the cylinder from the inflator, weighing it to ensure that is not less than 1.0 gram of the gross weight stamped on the cylinder itself.

Leakage test is the process of inflating the vest through the oral tube and by using a table grid supplied by the manufacturer, measure barometric pressure at certain intervals to ensure no leakage.

Depending on the type and severity of repair required on any Life vest/jacket, this may be carried out by the service company or as in most cases, be returned to the manufacturer for repair/ re-certification. If there are major repairs required, it may be more cost effective to replace rather than proceed with repair.

Flotation vests that have passed their periodic inspection shall be issued a maintenance release and returned to service.

PFD,s alone are only effective for a limited period of time (TSO requirements are that Life Jackets should keep passengers afloat for a twenty four hour period), realistically hypothermia would win out to drowning as a killer for passengers kept at sea for an extended period.

A final and major safety component on-board aircraft is the Life Raft.

Life Rafts are an essential component to long term survival when rescue efforts are not immediate. They allow for passengers to escape the perils and offenses of floating in the water and have played an essential part in those who survived previous ditching situations. The survival kit components: medical kits, fishing kits, canopies are elemental to prolonging life while rescue is pending.

The options for Life Rafts available and the configurations under which they are best suited provide for a wide variety of products available in the market. The person selecting the rafts for the aircraft should take into consideration their regulatory status (FAA, CAR's), the passenger capacity of their aircraft and the typical flight path (close to shore or far from shore) to make the wisest determination of the need for rescue.

An important reminder is that rafts should be TSO approved. An approved raft will have been designed and repeatedly tested to prove that it will function reliably for its intended purpose. Non TSO'd rafts do not necessarily have to prove this to be sold in the marketplace.

As the old advertisement goes........"an educated customer is our best customer". Certainly the consumer who understands the parameters under which they will be using each life raft will be able to make the wisest determination on what type of a raft to own and what types of equipment to have on it.

Most manufacturers accommodate special requirements where the packaging constraints requested are compatible, but some "must-haves" are a canopy, self-erecting or not, a radio beacon, water supply, first aid kit, fishing kit, and the raft patch kit, of course. Most of these are standard to the survival kit. The radio beacon is the exception, as customers tend to believe that the beacon in their aircraft is sufficient. I would argue, that in rough seas, if the raft were separated from where the aircraft first went down it would be most beneficial to have the rafts radio beacon active.

One question is when GPS technology will be valued as incorporated in the survival kits? There is already a TSO for such devices and these devices are available, but the cost at times outweighs the potential for benefit for most customers, at least for the time being.

Once a raft has been selected for use on-board aircraft, they must be inspected/maintained at certain intervals consistent with other such safety equipment discussed already. The interval at which a raft is due for service is dependent on use, authority having jurisdiction, and manufacturer recommendation. However, most commonly rafts are to be inspected/serviced and maintained annually by an approved AMO.

Annual inspection of life rafts, generally consist of the following:

• Raft removal from carrying case

• General Life Raft visual inspection

• Survival equipment and accessories inspection

• Light and battery assembly inspected

• Leakage tests

• Inflation system test/inspect

• Re-pack as per manual configuration

• Issuance of Maintenance release

Due to the extensive nature of this type of service it is mandatory that trained, experienced and certified personnel only, be permitted to conduct work on these appliances. If no such personnel exist, the raft must be sent to the manufacture for inspection, maintenance, repair and certification.

The intention and purpose of the above information is to bring to light the fact that safety equipment, on - board aircraft, can impact the survival of all involved in a crash or successful ditching and the importance of maintaining these types of equipment in such circumstances.

The importance of annual maintenance on these safety items can be likened to that old saying......."An ounce of prevention is worth a pound of cure".

Keith Burke

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