In the mid-1990s, the Safety Performance Analysis System (SPAS) allowed the data to be consolidated and displayed, to allow Principal Inspectors to analyze the combined results of surveillance data and other information.
These NPG, PTRS, and SPAS are the primary tools that are used for most all certificate holders at present. However, review activities such as the 90-Day Safety Review pointed out important limitations to the capabilities provided by them. The surveillance program was not as systematic as possible and had no structured tools with which to identify risk and manage the oversight program accordingly. Furthermore, the NPG's required items often do not reflect the differences between certificate holders' situations or the complexity of large certificate holders. More was needed.