Timothy Marker

Twelve full-scale tests were conducted in a modified Metroliner fuselage to study the impact of using improved fire retardant materials and a cabin water spray system on postcrash fire survivability. Currently, computer category aircraft as defined in Part 23 are exempt from meeting the stringent Federal Aviation Regulations (FAR’s ) requiring seat cushion fire blocking layers and low heat/smoke release panels in large transport aircraft.

A zoned cabin water spray system switch allowed for the individual activation of spray zones depending on cabin temperature was designed and installed in the fuselage. The system consisted of four 100 inch long zones, each system containing 6 nozzles. Of the twelve tests, five were run with the water spray system and a different combination of cabin materials. These five tests were repeated without the water spray system in order to establish baseline data for each material combination.

Two additional tests were conducted to investigate the impact of a partially obstructed forward exit and also to evaluate the effect that the channel-type floor geometry used in the Metroliner aircraft has on flame propagation during a cabin fire. Temperature, smoke levels, and gas concentrations were continuously monitored at a forward cabin location and each test was recorded on video.

Thomas L. Reynolds, Kent Porter

The concept of utilizing a cabin water spray system (CWSS) as a means of increasing passenger evacuation and survival time following an accident has received considerable publicity and has been subject to testing by the regulatory agencies in both the United States and Europe.

A test program, initiated by the CAA in 1987, involved the regulatory bodies in both Europe and North America in a collaborative research effort to determine the benefits and “disbenefits” (disadvantages) of a CWSS.

In order to obtain a balanced opinion of an onboard CWSS, NASA, and FAA requested the Boeing Commercial Airplane Group to investigate the potential “disbenefits” of the proposed system from the perspective of the manufacturer and an operator. This report is the result of a yearlong, cost-sharing contact study between the Boeing Commercial Airplane Group, NAAA and FAA.

Delta Air Lines participated as a subcontract study team member and investigated the “return to service” costs for an aircraft that would experience an uncommanded operation of a CWSS without the presence of fire. Disbenefits identified in the report include potential delays in evacuation, introduction of “common cause failure” in redundant safety of flight systems, physiological problems for passengers, high cost of refurbishment for inadvertent discharge, and potential to negatively effect other safety systems.

National Transportation safety Board

This publication presents the record of aviation accidents involving revenue operations of U.S. Air Carriers including Commuter Air Carriers and on Demand Air Taxis fro calendar year 1990.

The report is divided into three major sections according to the federal regulations under which the flight was conducted - 14 CFR 121, 125, 127 scheduled 14 CFR 135, or Nonscheduled 14 CFR 135. In each section of the report tables are presented to describe the losses and characteristics of 1990 accidents to enable comparison with prior years.

Patricia Cahill

Full-Scale fire testing was conducted in a furnished aircraft cabin to compare a currently used thermoplastic material with low heat and smoke release characteristics used in forming seat components. This testing was conducted due to questions concerning the exemption of seat components from the heat release and smoke requirements mandated for certain large surface area components in the aircraft fuselage. Results of the full-scale testing showed no significant difference in temperature, smoke levels, or oxygen depletion between the two materials. While carbon monoxide and carbon dioxide emissions were slightly higher with the currently used material, it cannot be concluded that this material was the cause. Based on the overall data, it appears that the small amount of seat component material is not significantly contributing to increased fire hazards.

Bishan Azad, Paul Poston

'This report presents a data base and a methodology for analyzing the feasibility of using antimisting fuel in the commercial aviation fleet and ,includes: a classification scheme developed to analyze major portions of the aircraft fleet; review of the available information on antimisting fuel; analysis of data collected on aircraft operations; and use of' life-cycle costing techniques to analyze the potential impacts of introducing antimisting fuel on a fleet-wide basis and segmentally. Aircraft were classified by number of engines and type of service. For each aircraft group, data were collected on the physical, operational, and economic factors that could facilitate or impede the introduction of antimisting fuel into specific portions of the fleet. These data were analyzed to determine if there are significant advantages to segmental introduction of antimisting fuel and, if so, which portions of the fleet are the most likely candidates for early introduction of antimisting fuel.

Analytical findings indicate that fleetwide introduction of antimisting fuel would maximize the benefit in terms of increased safety. However, segmental introduction may be preferable in terms of lower costs tand potential capacity constraints. Furthermore, the importance of two-engined, regular-bodied turbofan aircraft in the, feet, combined with the relatively low anticipated cost impacts in this segment, suggest that these aircraft may be the best candidates for early introduction of antimisting fuel.