Photograph of people observing a Learjet 23 fuselage undergoing testing in a hydrostatic tank, January 15, 1964. William P. Lear (in vest) is on the left.Typed caption on verso: "Meets FAA requirements: / Both fail-safe and ultimate fatigue tests…
Photograph of the Learjet 23 prototype at a Lear facility, September 10, 1963. Other aircraft undergoing construction and testing are visible in the background.Inscription on verso: "P 15-E / Sept. 10, 1963."
Photograph of the Learjet 23 prototype at a Lear facility, September 10, 1963. Other aircraft undergoing construction and testing are visible in the background.Inscription on verso: "P 15-D / Sept. 10, 1963."
Photograph of the Learjet 23 prototype undergoing fuel tests at the Lear Let plant in Wichita, Kansas, circa 1963.Inscription on verso: "Fuel tests."Stamped on verso: "Sep. 6, 1963."
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 the Learjet 23 prototype undergoing a fuselage side-bending test, February 25, 1964. Text on sign: "Fuselage side bending static test / 67% ultimate / 25 Feb. 2964."Inscription on verso: "Gene Koenig / middle white shirt / T-58-4E /…
Photograph of the Learjet 23 prototype undergoing a fuselage side-bending test, February 25, 1964. Text on sign: "Fuselage side bending static test / 0% ultimate / 25 Feb. 2964."Inscription on verso: "T-58-4C / 2-25-64."
Photograph of the Learjet 23 prototype undergoing a fuselage side-bending test, February 25, 1964.Text on sign: "Fuselage side bending static test / 0% ultimate / 25 Feb. 1964."Inscription on verso: "T58-4A / 2-25-64."