None. Basically as stated within the first 15 minutes death by friendly fire or crashes or ditches don't count. However, I still go over the logs and double check those just in case the deaths were not the result of enemy action. I know in this FSO there is no way opposing forces can engage in 15 minutes but in the past there were FSO where it was possible. So we always try to double check and make sure it is more a case of .. something let loose with their cannon, they dropped bombs on take off and killed people, or they tried to take off a carrier heavily loaded (I have a heck of time doing it myself in an F4U) and ditched in the sea.
After 15 minutes all deaths count.