Summary
A Pelican dropship attached to the Pillar of Autumn. It was sent out with Captain Keyes, Sergeant Johnson, and a few other marines (including Private Wallace Jenkins and Private Manuel Mendoza) in hopes of finding an abandoned weapons cache. Twelve hours after the last transmission from the pelican, the Master Chief dropped into the swamp aboard Echo 419 and found the wreckage of 933. Apparently, the Pelican had been ambushed on takeoff or landing. Whether the vessel was brought down by hostile fire from the Covenant or the Flood is unknown.
One of the pilots managed to record a last message, in case anyone found the dropship:
"Dropship Victor 93-(static)-the Pillar of Autumn-(static)-eed assistance. We are under att-(static)-attack by some kind of puff-(static)-it isn't Covenant. (Static) Captain Keyes has been captured by hostiles. (static)-dug in at a large structure in a swampy area. We need to pull out. Please-(static)-I will set this message to repeat at-(static)-given interval. Dropship Victor 933, clear."