The Northwest Airlines flight from Minneapolis to Chicago crashed on landing at Chicago Airport on 6th January 1947. Salvaged mail was forwarded in a Post Office Department envelope with an explanatory note. This partially burnt cover posted in Minneapolis on January 6th has both the explanatory note and the ambulance cover. On the back of the salvaged cover is a four line cachet ‘DAMAGED DUE TO AIR MAIL / INTERRUPTION NEAR / CHICAGO ILL / JAN 6 1947’ (Sanford Ref. 470106)