Accident Plane 25678 Chicago Dec 4 1940
CIVIL AERONAUTICS BOARD
1940
<a class="external free" href="https://en.wikisource.org/wiki/Page:CAB_Accident_Report,_United_Airlines_Flight_21.pdf/27">https://en.wikisource.org/wiki/Page:CAB_Accident_Report,_United_Airlines_Flight_21.pdf/27</a>