Hi Don,
Well known MiG17 around here, flown by Randy Ball, the highest time MiG17 pilot in the world I believe. Interesting aside, Randy's heart had a big problem a few years ago, a valve disintegrating I believe, as he flew the MiG from one air show location to the next. Realizing that he was in serious trouble, he cranked his oxygen level to the max and made a mayday call. He was able to remain semi conscious as ATC expedited his descent to the nearest field where he landed with emergency service scrambled and waiting. He was rushed to a hospital where he underwent open heart surgery and had a pig valve implanted in his heart.
His surgeon told him, during his rehabilitation, that the odds of anyone surviving his condition if they were standing in a Wal Mart when it took place, were slim to none. So I guess that you could interpolate that comment to determine what the odds were for a guy flying a vintage supersonic fighter jet at altitude above the clouds when it happened.
Randy is a pretty tenacious guy, imagine approaching the Feds to get your medical back after that series of events, but there he is flying his MiG.