The emission factors and optical properties of smokes produced by the burning of aviation fuel were determined from airborne measurements. These rather large fires (30 m in diameter and containing as much as 4.5¿104 L of fuel) produced dark columns of smoke. On several occasions the smoke was observed to continue to rise slowly after its initial stabilization at a temperature inversion. This rise was evidently due to the absorption of solar radiation by the smoke. ¿American Geophysical Union 1990