Airmail cover franked with 1929 15c on 1c green AIR surcharge issue (SG 117) tied by CRISTOBAL cancel dated MAY 24 1929. Flown on the FAM 9 Cristobal - Buenaventura, Colombia first flight with boxed first flight cachet on front and arrival marks on reverse. (AAMC #CZ34, Muller #20a)