Identifier1995-06-23-17_image_007SourceThe David D. Hatfield Aviation Photograph Collection (1995-06-23-17), Print Box 8, Folder 5DescriptionPhotograph of a pilot writing a message on a Boeing PW-9D "blackboard plane," California, circa January 1929. The chalk message on the fuselage reads: "N.N.W. Clear San Diego. 5000 ft. OK?" The PW-9D blackboard planes were used to send messages to the crew of the radio-less "Question Mark," an American-built Fokker C-2A, during their record-setting endurance flight in 1929.
[Pilot writing message on Boeing PW-9D "blackboard plane"], [1995-06-23-17_image_007]. Museum of Flight Digital Collections, accessed 16/10/2026, https://digitalcollections.museumofflight.org/nodes/view/3349