GOD'S OWN THERMAL (so you know it's true)

Looking over the airport in preparation to land, we were startled by a peculiar white shape like a giant piece of meringue pie covering half the paved tie down area.  Odd, then suddenly obvious.  It was emanating from a large propane tank.  That's right, several hundred cubic feet of pressurized explosive gas was venting across the pad between lines of parked planes (all containing fuel) and spreading out right below us.  Granted, propane is a heavy gas (until it ignites), but a 2-33 is heavier.

Being only a thousand feet up, our options at that point were few, but removing ourselves from the apex of an imminent fireball was job one.  Ideal training opportunity.  I had the student glide directly away as far as we could before turning back, then fly a straight-in approach and land short in the corner of the airport furthest from harm's way.

Because propane is naturally odorless, manufacturers add a foul smelling chemical so people can detect leaks.  On late approach that stench was thick in the air.  Unbeknownst to us, by then the entire neighborhood had been evacuated and fire trucks were pulling in to spray everything with water and remove flammable residues!  Parked clear of the runway, we were happy to sit in the cockpit awhile, watching from three thousand feet shy of the action with our bird's canopy between us and the sirens - whence a violent pressure wave still might rush forth at any moment.  Wanna cigarette?

Later, someone on the scene who knew stuff opined that if the vapor had erupted beneath us our perch atop the fireball wouldn't have lasted; a second later we'd have been deep inside it.  Cool.

The guy who knocked the valve off that tank?  Arse and elbows as some like to say, at Olympian speed despite big heavy work boots.  No one knows if he's stopped running yet.