As the budget for the development and production of new military aircraft tightens, modification of existing aircraft (MOD) has become increasingly important. This shift in emphasis has created a need for a high level parametric cost estimating method to estimate the cost of a MOD program early in the planning cycle. This report is the first volume of a series of reports documenting a multi-year project to support Naval Air Systems Command initiative to develop parametric cost estimating models for MOD programs. This volume provides an overview of the project, including a review of prior studies, the structure of data to be collected, and the forms used in data collection. Due to the proprietary nature of MOD program cost data, distribution of all future volumes of the report series except for the summary volume will be limited to selected Department of Defense agencies only. Military aircraft, Naval air systems command, MOD, Aircraft modification, Cost estimating, Work breakddown structure, Budgets, Acquisition, Government procurement, Naval Aviation Depots(NADEP), Weapon systems. (jg)