The NIC (investpromo.gov.iq) holds the "Investor's Map" which is a companion to the AIP PDF. They provide the PDF as part of the "Opportunities Booklet."
The contractual authority for AIP comes from (Contract Work Hours and Safety Standards) and specific clauses in each Task Order. The critical reference number you need to search for is DPAP 2005-01 (Defense Procurement and Acquisition Policy memorandum on Incentive Fees).
Outlines fees for landing, parking, and air navigation services. Book 2: En-route (ENR)