Photograph of the Learjet 23 prototype undergoing a fuselage down-bending test, February 18, 1964.Text on sign: "Fuselage down bending static test / 0% ultimate / 18 Feb. 1964."Inscription on verso: "T58-2-O / 2-18-64."
Photograph of two men looking at the door of the Learjet 23 prototype, February 18, 1964. A third man is visible inside the aircraft performing a test with an oscillograph.Inscription on verso: "Direct read out oscillograph loaned from Century…