The Type Certificate Data Sheets (TCDS) database is a repository of Make and Model information. The TCDS is a formal description of the aircraft, engine or propeller. It lists limitations and information required for type certification including airspeed limits, weight limits, thrust limitations, etc. TCDS documents are available from the initial implementation of this database (April 1999) forward. Historical documents prior to implementation are not necessarily included in this database; however, historical information will be retained as additional documents and revisions to documents are incorporated into the database. Revision History refers to those documents that have been revised through a TCDS revision. Current documents refer to those that are the most current. When looking at the TCDS and Model information in any of the Revision History views, the checkmark indicates the current documents.