R G W Cherry & Associates Limited

A benefit analysis has been carried out to derive the life saving potential of a Cabin Water Spray system in conjunction with enhanced Fuselage Burnthrough Protection from large external pool fires. The effects of fire and evacuation related requirements that were introduced after the accident date have also been taken into account.

All benefits derived are based on the number of lives saved for the world fleet of western-built aircraft type certificated for more than 30 seats and are relative to the period 1967 to 1996.

Two configurations of Cabin Water Spray system have been considered in the benefit analysis - a Modular and a Singular system. It is assumed that a Modular system would consist of three separate water supplies located in the front, mid and rear sections of the fuselage and would be activated only in the areas affected by fire. A Singular system would have only one source of supply located in the centre section of the fuselage. It would provide benefit in this area should the nose and/or tail sections became detached in the accident.

Benefit has been determined for aircraft configurations having either enhanced Fuselage Burnthrough Protection or a Cabin Water Spray System. In addition, the study reassesses the benefit from Cabin Water Sprays on aircraft already configured with enhanced Fuselage Burnthrough Protection.

The analysis has been accomplished by analysing past accidents to western-built aircraft over the period 1967 to 1996. Two methodologies were used to determine the total assessed benefit for all accidents studied. The first was based on an assessment of the number of lives saved in each accident from which a determination was made of the average number of lives saved per year and its likely range. The second method was to determine the rate of occurrence per year of the number of accidents from which the improvements considered might yield benefit.

The merits of each method are discussed and it was considered that the best prediction of benefit is that derived from Method 2.

Enhanced Fuselage Burnthrough Protection has been reassessed and the life saving benefit increased from that previously estimated. The number of lives saved per year is estimated to be approximately 12.

The assessment for a Singular Cabin Water Spray system on aircraft that are configured without enhanced Fuselage Burnthrough Protection is approximately 27 lives per year.

The number of lives saved per year, by a Modular Cabin Water Spray system, on aircraft that are configured without enhanced Fuselage Burnthrough Protection is assessed to be approximately 34 lives per year.

The assessment for Singular Cabin Water Spray systems and enhanced Fuselage Burnthrough Protection combined is approximately 34 lives per year.

The number of lives saved per year by Modular Cabin Water Spray systems and enhanced Fuselage Burnthrough Protection combined is assessed to be approximately 46 lives per year.

For aircraft that are configured with enhanced Fuselage Burnthrough Protection, Cabin Water Spray systems would save a further 22 lives per year for a Singular system, and 34 lives per year for a Modular system.

David Blake

This report documents a series of tests to determine the amount of positive pressure differential between the flight deck and surrounding areas necessary to prevent smoke from penetrating into the flight deck. The testing also explored methods to demonstrate the effectiveness of those ventilation conditions. The tests were conducted on the ground in a Boeing 727-100 freighter and a 747SP aircraft. A thin plastic sheet covering the flight deck door opening and a theatrical smoke generator were successfully used to demonstrate a positive pressure differential that was effective at preventing the penetration of theatrical smoke into the flight deck of the B-727. The 747SP ventilation system was not capable of preventing smoke penetration during these ground tests.

John W. Reinhardt

This technical note presents the updated version of the minimum performance standards (MPS) that a Halon 1301 replacement or alternate system for aircraft cargo compartment must meet as part of the aircraft certification procedures. This standard considers gaseous and nongaseous fire suppression systems for full-scale fire testing. The Federal Aviation Administration developed this MPS in conjunction with the International Aircraft Fire Protection Systems Working Group (formerly know as the International Halon Replacement Working Group).

David Blake

The purpose of this testing was to determine the temperatures that would cause self-activation of sodium chlorate oxygen generators. The data will be used to establish the degree of thermal protection that would be required to prevent the activation of chemical oxygen generators should they be exposed to heat from a cargo compartment fire involving other materials. The minimum temperature that caused the activation of one of the generators was 600°F. Due to uncertainties with other designs not tested and the physical properties of sodium chlorate, it is recommended that the generators not be exposed to temperatures above 400°F.

Robert Filipczak and Richard E. Lyon

The Ohio State University (OSU) Rate of Heat Release Apparatus specified in FAR Part 25.853(a-1) defines both apparatus test conditions and pass/fail criteria for large surface area aircraft interior materials, such as sidewall panels, bulkheads, and stowage bins. The cone calorimeter (ASTM E-1354 Standard Test Method for Heat and Visible Smoke Release Rates for Materials and Products Using an Oxygen consumption Calorimeter) similarly measures heat release rates from materials subjected to a constant external heat flux. However, heat release from the cone calorimeter is calculated by measuring the decrease in oxygen concentration in a stream of air flowing over the test specimen, rather than the temperature (enthalpy) increase of the air stream leaving the device, as is done with the OSU Rate of Heat Release Apparatus. This report will examine the differences between measurement of convective, radiant, and total heat release rates, and discuss techniques to obtain substantial conformity between the two techniques. Results for both methods are compared for single-ply, bisphenol-A epoxy-impregnated glass cloth.