- Author
-
Civil Aviation Authority
- Title
- Cabin Water Sprays for Fire Suppression: Design Considerations and Safety Benefit Analysis Based on Past Accidents.
- Coporate
- Civil Aviation Authority, London, England
- Report
-
CAA Paper 93010
August 1993
297 p.
- Keywords
-
mist
|
water sprays
|
aircraft compartments
|
fire suppression
|
safety
|
accidents
|
methodology
|
databases
|
occupants
- Identifiers
- life saving benefit
- Abstract
- A study of accidents to civil passenger aircraft over a 26 year period has been made. In this period there were 95 accidents, reported as potentially survivable, in which fatalities and fire occurred. From an analysis of these accidents a potential life saving benefit for cabin water spray systems has been obtained. In the analysis of past accidents the life saving resulting from the inclusion of current mandatory safety features, such as seat fire blocking, was first estimated. Thus the analysis attempts to calculate the benefit, as a further incremental life saving, if cabin water spray systems were to be fitted to today's standard of aircraft which incorporate fire safety improvements introduced over the 26 year period studied. Test data from full-scale fire tests has been used to predict the extension in survival time for cabin occupants as a result of the use of cabin water spray. Accident fire hazard and evacuation mobility profiles have then been used to calculate the life saving potential. The database of 95 accidents has been used to indicate the necessary design features of a cabin water spray system, such as crashworthiness objectives and means of activation. Consideration has been given to the effect on the predicted cabin water spray benefits resulting from the introduction of new requirements concerning seats of enhanced crashworthiness and low heat release cabin interior materials. The expected growth in aviation and the accident trends over the 26 year period, 1966 to 1991, have been considered in predicting the future benefit of cabin water spray systems. As a result of the 95 accidents which were studied in this report fire claimed 2407 fatalities. It is calculated that design changes which are now mandatory would, if they had been fitted at the time of these accidents have preveted 35% of these deaths. Cabin water sprays could have provided an additional benefit of 15%. For nearly half the fatalities are a result of occupants, some severely injured, being engulfed in fuel fires, often when no longer within the cabin as a result of its complete destruction following impact. In many instances the cause of death is, correctly, recorded as due to the fire. However the traumatic injuries received may well have proven fatal if the fire had not reached the victim first. It is concluded that today cabin water sprays would save on average 14 lives per year world-wide. When the calculations are performed taking account of only the aircraft operated by the airlines of the nations comprising the JAA, the FAA and Transport Canada this figure reduces to 6 lives per year. Fire safety improvements made in recent years are fulfilling their safety objectives. There is a continuing reduction in the rate of accidents involving fire and in the number of fatalities due to fire in these accidents. It is believed that continuing fire safety and cabin evacuation improvements will ensure that this trend continues. It is expected that in the future any cabin water spray benefit will remain at a constant average life saving per year despite the expected growth in aviation. It should be borne in mind that the 'real world' does not conform to this idealised annual average. There exists at any moment a finite risk of an accident occurring which may involve a major loss of life.