Hot Surface Ignition and Aircraft Safety Criteria

A recently completed experimental program to quantify minimum hot aurface ignition temperatures for flammable fluids encountered in aircraft engine compartments is reviewed. A highly realistic test article composed of a segment of an F-100 engine was used to provide actual engine compartment (F-16) geometries and clutter. The hot surface was an air heated bleed air duct. The effects of many variables were investigated including pressure, temperature, fluid impingement scenario, and ventilation velocity. The paper reviews some of the results of the program, presents some results from other related efforts, suggests a “Safe Design Temperature”, presents a “probability of ignition” for various fluids as a function of surface temperature and outlines a methodology for hot surface hazard analysis.