Though differences in rank within military teams help to define responsibility, they may hamper necessary bottom up communication, jeopardizing performance and safety. In aviation, lack of bottom up communication was attributed to lack of assertiveness in junior team members, providing them with assertiveness training as a consequence. However, failing upward communication may not only be related to junior member's characteristics but also to lack of responsiveness of the senior member. It was the purpose of this study to examine the connection between rank, assertiveness, responsiveness and team potency as indicator of effectiveness in teams. Data were provided by 67 military crews, consisting of pilot and observer, during training-missions in a Naval Helicopter high fidelity simulator. In a post-flight questionnaire, both crewmembers provided ratings of the other member's assertiveness and responsiveness, and gave their own rating of team potency. Results show a negative impact of pilot's rank on observer's assertiveness, while observer's rank was not related to pilot's assertiveness. The higher the pilot's rank, the higher the observer's responsiveness, and the lower his own responsiveness, both irrespective of observer's rank. The higher the observer's rank, the more responsive the pilot was, again, irrespective of the pilot's rank. Both crewmembers' rank was related positively to their own rating of team potency, but not to the rating by the other member. A consistent positive connection was found between responsiveness and team potency; pilot's responsiveness was related positively to team potency as indicated by the pilot as well as the observer. The same pattern was found for the observer's attributed responsiveness. These results confirm that responsiveness is essential in multi-rank military teams, with important consequences for Mission Command. Therefore, it is incorporated into existing initial and advanced RNL Navy Crew Resource Management training, to enhance mission readiness in our Navy and Marines.