Early Jetliners Had Frequent Catastrophic Failures Due To?
Answer: Square Windows
Early development in any industry is fraught with hiccups, setbacks, and outright failures, and the development of early jetliners is no exception. The first production commercial jetliner, based off of earlier military designs, was the British De Havilland DH 106 Comet. The aircraft paved the way for future jetliners and, through a series of catastrophes, helped shape the design of modern jetliners.
Three early DH 106 flights resulted in catastrophic failure of the aircraft, with the entire fuselage breaking apart mid-flight at high elevations. Although the incidents were initially blamed on adverse weather conditions, further research indicated that the accidents occurred as a result of metal fatigue in the frames induced by air pressure (an aspect of metal engineering poorly understood at the time given the infancy of the entire aeronautical engineering field). Among all the points of stress on the frame, it was discovered that the square windows were creating exceptionally high levels of stress at their corners and that the window design had directly contributed to the fatigue behind the three tragic accidents that grounded the DH 106 line.
The jet was extensively redesigned with oval windows, and rival manufacturers followed along with oval window designs of their own. To this day, over half a century later, jetliners still have oval windows as a simple precaution against fuselage stress.
Image courtesy of the British Imperial War Museum.