Fortunately, I've never seen anyone get killed and hope I never do.  But a couple of friends came pretty close a couple of weeks ago here at Arlington Muni while I watched helplessly. 

They were flying a Blanik L-23 glider--a two-place glider of moderate performance and an excellent trainer.  I'd just finished lunch at the Taildragger cafe and walked outside to take a look around before heading back to the hangar.  To my surprise an L-23 was coming in very low over the trees east of the runway, very slow, brakes extended, perpendicular to the primary runway.  It looked like the nose was bobbing up and down in an incipient stall.  They had plenty of altitude to make the airport, not going to land off-field, but instead of continuing straight ahead over the perpendicular runway and landing in the open grass to the west, they tried to make an extremely low-altitude 90 degree left turn to try to make the glider strip, right into the area where a group of pilots was standing around their gliders waiting for a tow.  To my horror, the left wing tip struck the ground, the right wing rose as the glider pivoted around the now stationary wing tip and slammed into the ground nose-low and came to a very abrupt stop. 

Nobody hurt, glider undamaged.  Amazing. 

Almost all accidents are the result of pilot error and nearly always occur at the end of a chain of events that accumulate until there is no escape, no options left.  Individually, the links may not be particularly serious errors or traps, but as they add up the window of opportunity becomes smaller and smaller, options become fewer and fewer.  Break the chain at any one of the links and the window may open, new options may become available allowing an escape.

So what were the links in this case, how could they have been avoided and how could any one of them been broken to allow an escape?

First, they must have gotten much too low approaching the airport, maybe flying into a headwind, misjudging their altitude in the hills miles east of the airport or tried to grab that last little bit of lift that would give them a better margin or even keep them aloft a while longer.

Hereabouts, a typical spring or summer day starts with calm winds and clear skies.  As it warms up cumulus clouds start popping, indicating lift, sometimes real boomers.  But as the day goes on the wind freshens from the northwest, the marine air comes inland, kills the lift and if you're too far east, trying to soar the mountains a few miles east of the airport, you can find yourself trapped, low, out of lift and having to fight a headwind back to the home 'drome.  I don't know if that's what happened, but they were mighty low, struggling to get home.

Link two:  My first thought after the intial shock of their low altitude was, "why do they have the brakes extended?  That makes no sense at all."  The added drag (and Blaniks have big, effective brakes) and resulting reduced lift were only making the situation worse.  If you're trying to extend a glide the aircraft needs to be in the lowest possible drag configuration, at max glide speed, gear and flaps up, certainly no air brakes extended.  I can't imagine what they were thinking.

Third:  They were slow, really slow.  The nose appeared to be bobbing up and down in an incipient stall, not quite breaking, but really close to it.  You don't want to stall any aircraft at very low altitude unless you're all done flying one foot above the runway.

Four:  The turn, at extremely low altitude, probably less than twenty feet, in an airccraft with a nearly sixy-foot wingspan, trying to line up with the runway instead of just landing straight ahead, with nothing but flat grass ahead. 

Creative thinking is hard to come by when stressed, as these guys obviously were.  Although one of them is an experienced pilot, a CFIG, who has landed-out before, when you're looking at familiar turf, the home runway, mind-lock may be hard to overcome. 

I remember one time flying my LS-1C glider in Ephrata.  I had been battling strong headwinds, at the end of a dying day and miles to go.  I finally got back to EPH after many cycles of circle in the dying lift while drifting downwind, race upwind while losing precious altitude, circle again in dying, weaker lift, repeat d.c. al fine.  When I finally got to EPH there was a strong crossind.  Fortunately, I was able to land, but after coming to a stop I was very concerned that when I opened the canopy I would get to watch a very expensive piece of plastic blow away.  As I sat there hoping the wind would dissipate another glider landed, but not on the runway and not into a crosswind.  He landed on the taxiway connecting the runway to the ramp, directly into the wind.  The wind was over twenty knots and his ground roll was very short.  Smart cookie and a piece of cake. 

Well, that's what the L-23 should have done:  forget about landing on the runway and making a dangerous low-altitude turn, just keep going and land straight ahead on the open turf.

Years ago, when ultralights first appeared, there was a training operation at the now gone Issaquah airport, flying Kasper Wings--single seat, weight-shift, pusher, tail-less flying wings.  Vitold Kasper had developed a very simple, swept wing design, originally a glider, with large rudders at the wing tips that could only be turned "out."  They would nearly pivot around a wingtip and could be landed at incredibly low speeds.  The wing swept back at about a fifteen degree angle (I'm guessing).  Taxiing, the aircraft had a pronounced nose-up attitude to give it a positive angle of attack for takeoff and the wing tips and tip-rudders were only a foot or two off the ground.  Training was given to aspiring pilots, with absolutely zero experience flying anything, by radio.  By radio!!!  How any of them ever survived is beyond me.  But a couple didn't survive.  While accelerating down the runway they inadvertently dragged a wing tip.  The dragging tip slowed the lowered wing almost to a stop, the engine kept pulling and the "up" wing accelerated.  As one tip stopped, the other accelerated and rose ever higher, finally arcing vertically overhead in an almost instantaneous one-hundred-and-eighty degree turn and then descended, crashing into the ground, virtually straight-in.

The pilots never got more than twenty or twenty-five feet of the ground and impact speed probably never exceeded forty knots.  But that was all it took, a low-speed, low-altitude, vertical impact.  As I recall, two were killed before they decided maybe it wasn't such a good idea trying to train neophytes in single-seat aircraft by radio.  

I had a student a few years later who had gone to another ultralight operation to learn to fly.  Same story:  single seat aircraft, training by radio.  He told me that before he took off on his first flight he was required to post a "damage deposit,"  in case something went wrong.  Sure enough, he stalled on takeoff, crashed into the ground and damaged the aircraft.  The operators had obvioulsy been through this before, because the deposit was just enough to pay for the damage.  Holy cow!

Fortunately, he was unhurt and didn't understand why I was so amazed he would attempt to fly anything without an instructor on board.  After all, he knew how to fly radio-controlled models!  Caramba!

A few years ago another friend was killed in his glider, trying to make a low-altitude 180 degree turn after a botched approach that resulted in over-shoot and subsequent low-altitude, low airspeed stall.

You don't have to fall very far or very fast to get killed.

Anyway, that was what I was expecting when I watched the L-23 drag its left wing tip as they tried to turn ninety degrees to land on the runway.  They had actually turned about 45 degrees when the wing tip struck ground.  Sure enough, the glider pivoted nearly ninety degrees around the now stationary wing tip, the "up" wing rose as it accelerated in an arc, the nose dropped and smacked the ground.  When the fuselage touched down the landing gear dug in and everything came to a sudden stop.

The whole chain of events, one poor choice after another, could have been broken at any one of the links, giving them a new range of options:

They could have started for home earlier instead of getting low.

They could have chosen a field within comfortable range to land-out instead of trying to force their way back to the home 'drome.

They could have left the landing gear and brakes retracted to reduce drag to help extend the glide.

They could have flown at best glide speed to get the best gliding range.

They could have landed straight ahead into the grass beyond the runway with room to spare.

They could have been killed.

Worse, when asked what had happened, the CFIG responded defensively, saying it was no big deal, they were just a little low, dragging the wing tip hadn't been a problem, everything worked out fine, no damage, no injuries, no worries, nothing to learn. 

Not good.