Quote:
“The Brits, not wanting to loose their lead kept the comet flying instead of grounding it until the problem could be identified and corrected which by the way was wing fatigue.
No it was fuselage rupture under pressurization.
Fatigue cracks developed because the Brits used square passenger window frames. The cracks propagated from the apex of the square window frames and allowed the cabin to explosively depressurize.
The design fix was to reshape the window openings as ovals eliminating the stress points. “
De Havilland had made the aircraft’s skin too thin, and the rupture started from the square shaped ADF aerial cutout panel. The passenger windows themselves were not the problem, but were at risk should the aircraft keep flying as it was. The fix to this was to use thicker gauge material for the aircraft skin and redesign the window shape. By the time those fixes were made, the damage to the Comet’s reputation was done, and just like with the DC-10 issues, I suspect that the 737 Max series will have a short run after this fiasco.
"Evidence of fatigue cracking was found that originated from the aft lower corner of the forward escape hatch (window) and also from the right-hand aft corner of the windows"
The most notable lesson learned from the Comet disaster is that viewing windows are no longer designed square but with rounded edges to reduce any stress concentrations. Another immediate lessons is that crack-stoppers are now placed between frame-cutouts that take the shape of circumferential stiffeners that break-up the fuselage into multiple sections and thus prevent the crack from propagating from one window to the next.
The final clue, revealing the weakness in the Comet’s structure, turned up on June 24 in the tank at Farnborough, where the immersed test Comet had been subjected to the equivalent of 9,000 flying hours. Instruments showed a sudden drop in cabin pressure, indicating that something had happened in the tank.
When the drains were opened and the water flooded out, scientists stared in grim amazement. Repeated pressurization had caused the fuselage to split. One fracture started in the corner of a window atop the aircraft where radio aerials were housed and continued for eight feet, passing directly through a window frame in its path.
Read more: https://www.smithsonianmag.com/history/comets-tale-63573615/#M587xiHY61qmw6ra.99 Give the gift of Smithsonian magazine for only $12! http://bit.ly/1cGUiGv Follow us: @SmithsonianMag on Twitter