(b) The airport layout plan, if in existence, must accompany the advance planning proposal. If the advance planning proposal includes preparation of plans and specifications, enough details to identify the items of development to be covered by the plans and specifications must be shown. The proposal must be accompanied by evidentiary material establishing the basis for the estimated costs under the proposal, such as an offer from an engineering firm containing a schedule of services and charges therefor.
[Doc. No. 6227, 30 FR 8040, June 23, 1965 as amended by Amdt. 151–11, 31 FR 6686, May 5, 1966]