This report is the first in Phase 2 of the Human Error in ATM' Project (HERA 2). It concerns the further development and investigation of human error, its prediction, detection and management within the Air Traffic Management (ATM) system. The purpose of the work is to assess how human errors are generated within a simulated ATM environment and, more importantly, how they are managed. This report not only discusses the errors found in these situations but also offers a methodology for future work in the ATM system.