Annotated chart, Khammouane Province, Laos, filed as 'Attachment 5' in the Boxer 22 search-and-rescue material. The hand-drawn red box encloses the Ban Phanop valley on Route 23 — a narrow, karst-walled river corridor heavily defended by anti-aircraft guns. In December 1969, after the F-4 call sign Boxer 22 went down here, Sandy A-1 Skyraiders and Jolly Green rescue helicopters fought a multi-day battle to recover the crew, in one of the largest and most costly rescue efforts of the Southeast Asia war. The airfield symbol at center is annotated BAN PHAN HOP/27/S — NOT USABLE. From the collection of Donald L. Engebretsen. Project: 218834