This Specification has been developed for the purposes of aircraft safety research and must not be used as a basis for influencing the design of any system to be used on an aircraft.

This Technical Specification relates to a Cabin Water Mist (CWM) system, forming part of an Integrated Fire Protection system. However, it is also applicable to a “stand-alone” system. Guidance in the design of a CWM system may be found in NFPA 750: Standard on Water Mist Fire Protection Systems, however, it should be noted that this standard is not aircraft specific and can not be considered as a specification for a CWM system to be installed on an aircraft.

In May 1992, the Joint Aviation Authorities issued a Draft Notice of Proposed Amendment (NPA) for Cabin Water Spray Systems. This document has been taken into account in the formulation of this Technical Specification.

The Federal Aviation Administration (FAA), Transport Canada, and the United Kingdom Civil Aviation Authority requested a Risk and Benefit Cost Model be developed to assess the likely number of U.S.-registered freighter fire accidents, and the benefit/cost ratio associated with seven mitigation strategies identified by the FAA. This report explains the data used by the Model, its algorithms, and the way in which the Model may be used.

The Model addresses the potential fire threat from all forms of cargo, including the bulk shipment of lithium batteries (primary and secondary) because they likely contributed to two of the five freighter fire accidents that have occurred on U.S.-registered airplanes. The Model displays the number of accidents through 2020 and costs, benefits, and the benefit/cost ratios through to 2025.

The Model prediction of the average number of accidents likely to occur from 2011 to 2020, if no mitigation action is taken, is approximately 6—with a 95-percentile range of approximately 2 to 13. If no mitigation action is taken, accident costs are likely to average approximately $44 million (U.S.) per annum over the period 2011 to 2025. The primary contribution to freighter fire accident costs is the value of the airplane—with values of approximately 90% of the total accident cost for the larger freighter airplanes. However, the Model predictions of accident costs are based on the assumption that the composition of the U.S.-registered freighter fleet will be largely unchanged from 2010 through 2025 in terms of the size and value of airplanes.

The costs of implementing the proposed mitigation strategies are currently not known to a sufficient level of accuracy to make accurate determinations of benefit/cost ratios. However, the Model has been constructed to allow user inputs of costs once they become available.

Click here to download the model (MS Excel 2007 or later, 140 MB)

This report reflects the many changes that have occurred in the aircraft fire suppression arena since the last update was published in 2002. Changes have occurred in regulatory restrictions, commercialized halocarbon replacements, halocarbon replacements in development, alternative technologies, and the evaluation of fire fighting effectiveness for the four primary aircraft onboard applications: (1) engine nacelles, (2) hand-held extinguishers, (3) cargo compartments, and (4) lavatory protection. Test-based fire suppression halon equivalency guidance is provided for these applications.