Escape and evasion map printed on playing cards distributed to Prisoners of War which could be soaked and pealed apart revealing the escape map. Many of the maps of the Pacific region were printed by the US Army Map Service, while the UK was responsible for many of the European Theatre maps. Many of the US Navy charts were folded in envelopes and distributed to the air crews before a mission, and to be turned in when the mission was successfully completed. They were called "drift charts" by the Navy, "...since their prime purpose was to indicate to aircrews survivors in their life rafts
Pilot certification in the United States vision deficient pilots, in many cases these restrictions can be removed through use of an FAA approved alternative office based color vision test, which if passed, the applicant must continue to retake that same test (or any other passable tests) at every renewal. If the pilot applicant is unable to pass any of the office based tests, a real world operational test is available. This test consists of a ground-based chart reading and control tower signal light test for Third Class medical certification (This is called the Operational Color Vision Test or OCVT), and in addition to that, a specialized