What was found
(LOG 5757502) ON DESCENT PASSING FL22.5, L1 WINDOW BEGAN ARCING, FOLLOWED QRH 1.13, PASSING 18,000 OUTER PANE BEGAN TO CRACK. FOLLOWED QRH 1.13 FOR OUTER PANE CRACK. REMOVED L1 WINDOW PER B737 AMM 56-11-11. (240485) INSTALLED L1 WINDOW REF B737 AMM 56-11-11.