A Reexamination of the Formation of Exhaust Condensation Trails by Jet Aircraft

Abstract

With the end of World War II, it became apparent that a study should be undertaken to identify the factors controlling the production of aircraft condensation trails (contrails). This early work provided a theoretical prediction of Te, the critical temperature at which the values of the relative humidity and pressure are such that the formation of the contrail phenomenon will occur. As empirical data were obtained, the general agreement at increased altitude was not precise and several studies were made to obtain both theoretical and empirical fits that would provide a ?yes/no? decision. These modifications did allow a better decision for the formation of contrails but were found to be increasingly inaccurate at greater altitudes. This study provides an improved algorithm that yields a theoretical prediction that is in general agreement with the available empirical data at all altitudes. It demonstrates that there is a need for additional effort in the identification and precision of relative humidity and pressure that are input to this computation.