As a part of the environmental process the Federal Aviation Administration (FAA) is required, in accordance with the FAA Airport Environmental Handbook, Order 5050.4A, to include a section in the Environmental Impact Statement (EIS) that addresses the purpose of a proposed project and why it is needed. Outlining the purpose and need of a proposed project is vital, as it allows for the identification of reasonable alternatives to the action, and the evaluation of the impacts of the alternatives.

At the beginning of every EIS the purpose and need of the action being considered are described in detail. For the South Suburban Airport (SSA) Tier 1 EIS, the proposed action was site approval for the location of a potential, future air carrier airport in the south suburban area of Chicago, and the purpose was to preserve the option to develop an airport in the future. The need for site approval was based on the continuing need to protect airspace and preserve a feasible site from encroachment by suburban development. You can read more about the purpose and need for site approval in Chapter 2 of the Tier 1 EIS.

Similarly, for the SSA Tier 2 EIS, a purpose and need for the proposed action must be formulated. The Tier 2 EIS is currently being written and will address development of the inaugural airport.