Thunderstorms along the Intertropical Convergence Zone played a role in the loss of Air France Flight 447 , which left Rio de Janeiro–Galeão International Airport on Sunday, May 31, 2009, at about 7:00 . local time (6:00 . EDT or 10:00 . UTC ) and had been expected to land at Charles de Gaulle Airport near Paris on Monday, June 1, 2009, at 11:15 . (5:15 . EDT or 9:15 . UTC) [8] The aircraft crashed with no survivors while flying through a series of large ITCZ thunderstorms, and ice forming rapidly on airspeed sensors was the precipitating cause for a cascade of human errors which ultimately doomed the flight. Most aircraft flying these routes are able to avoid the larger convective cells without incident. [9]

While most of the tests deal with the convergence of infinite series, they can also be used to show the convergence or divergence of infinite products . This can be achieved using following theorem: Let { a n } n = 1 ∞ {\displaystyle \left\{a_{n}\right\}_{n=1}^{\infty }} be a sequence of positive numbers. Then the infinite product ∏ n = 1 ∞ ( 1 + a n ) {\displaystyle \prod _{n=1}^{\infty }(1+a_{n})} converges if and only if the series ∑ n = 1 ∞ a n {\displaystyle \sum _{n=1}^{\infty }a_{n}} converges. Also similarly, if 0 < a n < 1 {\displaystyle 0<a_{n}<1} holds, then ∏ n = 1 ∞ ( 1 − a n ) {\displaystyle \prod _{n=1}^{\infty }(1-a_{n})} approaches a non-zero limit if and only if the series ∑ n = 1 ∞ a n {\displaystyle \sum _{n=1}^{\infty }a_{n}} converges .