Golf War: Flaming Blimp Crashes Down on US Open, Cause Unknown (PHOTOS, VIDEOS)

Eyewitnesses watched the blimp, advertising federal credit union PenFed, catch fire and hit the ground at about 11:15 a.m. on Thursday morning. The blimp was owned and operated by aerial advertiser AirSign, which reported that the pilot is okay in an interview with the Journal Sentinel.

"There was a small fire, it looked like on the front, and it was just deflating and going down," said witness Hunter Guetzke to local outlet WISN 12. "There was like, two or three explosions, probably from gas tanks on the blimp."

"It started deflating, and then it started going down," added witness Bryan Rosine to the Journal-Sentinel. "They were trying to give it some throttle and it didn't go up.  Then there was a bunch of kabooms and smoke clouds."

Contrary to some eyewitness reports that described someone parachuting out of the flaming aircraft, the pilot stayed with the blimp as it descended, and was pulled from the burning wreckage by a crew member.

ESPN reported that the pilot was "alert and conscious" shortly after the incident, and he was transported by helicopter to a local medical facility. He was the only one aboard the blimp, according to local police.

The cause of the deflation and fire is unknown. "They were going to use it all week," said Dan Coffey, who owns the airstrip the blimp took off from. "He was flying it for hours. I don't know if the wind caught up with him or what."

"These airships are FAA approved. They make sure that everyone is inspected. This is an extremely rare accident."