FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
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AVIATION MEDICINE REPORTS

Report No: DOT/FAA/AM-99/10

Title and Subtitle: Aircraft Evacuations onto Escape Slides and Platforms II: Effects of Exit Size

Report Date: April 1999

Authors: McLean, G.A., George, M.H., Funkhouser, G.E., and Chittum, C.B.

Abstract: Experiments were conducted to examine the effects of exit height on subject flow rates during simulated emergency evacuations from an aircraft fuselage. Egress was through (modified) Type-I exits, using inflatable escape slides and doorsill-height platforms configured with ramps for descent to the ground. A single-aisle aircraft simulator was equipped with 30-inch wide rectangular floor-level exits variously configured to achieve overall exit heights of 48, 60, and 72 inches. Human research subjects, ranging in age from 18 to 40 years, evacuated through the exits to the ground via both platform and slide egress routes. A (2 X 3) repeated-measures, counterbalanced research design was employed to control trial order effects. Analysis of variance revealed overall main effects of egress route (p.001) and exit height (p.012), and a nearly significant interaction of egress route with exit height (p.062).

The main effects occurred because the egress onto the platform was much faster than the slide, and egress slowed monotonically as the exit height was reduced. The trend toward an interaction effect of egress route and exit size occurred because reducing the exit height to 48" significantly slowed egress onto the inflatable escape slide (p0.017) but not the platform (p.41). This discriminative effect resulted from the hesitation that subjects displayed when using the slide, relative to the platform, especially at the shortest exit size studied. The increased egress time onto the escape slide appeared to result from a more difficult entry onto the slide, as the lower door heights required subjects to bend over more to enter the slide. This made the typical "jump-and-slide" maneuver much harder to perform. Egress ratings for exits that conform to the dimensions used in this study should reflect these findings, especially when escape slides are the likely egress route.

Key Words: Aircraft Evacuation, Motivation, Escape Slide, Competitive Behavior

No. of Pages: 11