1000 of same model flying 12 hours a day (utilisation is nearer 11[1], Some airliners where made in numbers a lot more than 1000, 737&#x27;s where over 8000[2]) for 20 years is 10000 flight years (very crudely).<p>438000&#x2F;10000 is 43.8, so 2.3% chance over 20 years.<p>It&#x27;s a longshot but it&#x27;s not never.<p>[1] <a href="http:&#x2F;&#x2F;web.mit.edu&#x2F;airlinedata&#x2F;www&#x2F;2014%2012%20Month%20Documents&#x2F;Aircraft%20and%20Related&#x2F;Total%20Fleet&#x2F;Average%20Daily%20Block%20Hour%20Utilization%20of%20Total%20Operating%20Fleet.htm" rel="nofollow">http:&#x2F;&#x2F;web.mit.edu&#x2F;airlinedata&#x2F;www&#x2F;2014%2012%20Month%20Docum...</a><p>[2] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_most-produced_aircraft" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_most-produced_aircraft</a><p>So yes the odds of any one plane experiencing that problem are absolutely tiny but across the fleet not so much.