With zero margin for error, three catastrophes are narrowly averted by pilots who somehow manage to land their damaged planes. 　　　<br><span style="font-size: 24px;">　</span><br><span style="font-size: 16px;"><strong>Case.1 Southwest Airlines Flight 1380 <br>Case.2 Aloha Airlines Flight 243 <br>Case.3 Air Canada Flight 797 </strong></span>