Flight Simulation: The standard flight simulation parameters are based on those for a Boeing 747 but can be modified to simulate other, including personal, aircraft. For the simulations, we assume that the airport is at sea level, the maximum cabin pressurization is equal to the atmospheric pressure at 7000 feet and the ascent/descent rate is 350 ft/min (for the cabin altitude). With the subject seated comfortably in the pressure-chamber, chamber pressure is decreased from ambient to ambient minus 2280 daPa (gauge pressure=-2280 daPa) over a 15 minute period, maintained at ambient-2280 daPa for 15 minutes (cruising) and then increased to ambient over a 15 minute period. The subject reports symptoms throughout and middle-ear pressure is measured bilaterally by tympanometry periodically.