Questions About DL Diversion
 

DL 79 on Oct 18, TXL-JFK, B767-300, diverted to St John (YYT) today. It spent 2+30 on the ground at YYT before continuing on to JFK. The cause reportedly was a problem with the cockpit oxygen system. Could anyone here speculate as to what happened? Did they discover that one or both O2 masks were INOP after flying all that way?