Two aspects of team communication, speech acts and communication problems, and their relation to team performance in a team air combat simulator were studied. The purpose was to enhance the understanding of how team performance is related to team communication. Ten Swedish fighter pilots and four fighter controllers of varying experience participated. Data were collected during fighter simulator training involving four pilots and one fighter controller in each of two teams. Speech acts were collapsed over seven categories and communication problems over five categories. Communication was studied from two perspectives: critical situation outcome and mission outcome. Some problems were closely related to particular speech acts. Speech act frequency, especially meta-communications and tactics, was highest when winning. However, the timing of tactics in critical situations needs further research. Communication problem frequency was highest for runs which ended equally. The most common problem was simultaneous speech, possibly because of the simulator radio system. The number of speech acts was related to enhanced performance but in a complex manner. Thus in order to work efficiently team members need to communicate, but to communicate sufficiently and at appropriate times. This work has applications for fighter pilot and controller team training and the development of communication standards.