Saturday, June 15, 2013

Failure to Aviate

I planned to attack a backlog of chores on Saturday June 15 since the wind looked too strong for flying.  Amy wanted to leave the house for the day, so after I quickly finished the most pressing tasks we decided to spend the day with Jeff, Lee, and Peter at Morningside.  We met at the park-and-ride parking lot near the Massachusetts - New Hampshire border and piled into Lee's vehicle.

The shaking trees in Newport, less than 20 miles (30 km) from Morningside, confirmed my concerns about the wind.  I was stunned to see limp wind socks when we pulled into Morningside.  I "double-checked" everything and indeed it looked calm.  I moved my hang point one notch forward, setup, and prepared take a quick flight before the day burst open.

Jeff finished rigging before me and took a sledder.  "How was launch?"  He replied, "light tailwind, but mostly calm".  Sounded good enough to check out the new glider configuration.

It was wafting over-the-back (opposite the wind above) when I arrived at launch.  I looked around and didn't see any other signs of wind in the LZ or along the ridge.  No problem; I'll wait.  There were brief lulls, but I've given up tailwind launches since moving to a smaller glider (Wills Wing T2C 136).  I was tempted by a couple longer lulls, but really wanted to see something coming in or at least a sustained period of no wind.

Patience paid off.  I watched the light tailwind subside and waited about 20 seconds with no activity before deciding to launch.  I have been trying to stretch my strides during the launch run, so I devoted some attention to that as I ran down the concrete ramp.  I knew things were not ideal when I reached the end with the glider still riding on my arms.  I powered forward with a strong kick as I felt the edge of the ramp under foot.  At this point I expected to dive away, gain airspeed, and buzz the trees below.  However, that didn't happen.

My first thought was the glider was folding up; I must have forgotten to attach the haul-back.  There was no pressure from the control frame; the glider wasn't flying or even dragging through the air.  The glider and I were falling as if I ran off the launch with the glider still folded in the bag.  I hit the ground (and a large rock) 80 feet (25 meters) below.  I hit hard.

I've had my share of abrupt stops.  Falling out of trees, falling off bikes at high speed onto asphalt, falling off buildings, crashing dirt bikes after failing to jump the last vehicle, spreading equipment and blood on poorly executed ski jumps, slamming head first into a wall on skates, and other shenanigans that I promised I would never divulge.  All those previous stops hurt, (at least I assume they did since I can't remember a couple), but this one was epic.  Immediately after impact I expected broken body parts; possibly broken legs and a messed up neck.  I knew the drill so I carefully inventoried body parts before moving.  Although hurting, everything seem to function.

I wiggled out from beneath the wreckage.  A breeze now blew into the hill and I had to rotate the glider around to keep it from flipping in the wind.  I walked a few yards up the slope and waved to the people below so they would know I was ok.  I found out later nobody saw the crash or me waving.  Only when I walked the glider back to the top did onlookers start questioning what happened.

Eric and a few others helped me finish carrying the glider up and over the top to a shady, but poison-ivy covered, spot out of the way.  The injuries were swelling, so after cleaning the blood from my face, Eric drove the ATV down with me standing on the back.  We had a good laugh when we rounded the lower bend and I exclaimed when seeing my old glider with the same sail pattern, "Oh, it was just a bad dream.  There's my glider in perfect shape!"

Amy drove Lee's SUV into town to get some ice while I more closely inspected my wounds.  I needed a lot of ice.  :-(

4-bagger!  (Photo by Lee Minardi)

Amy drove me back to launch and helped pack the glider.  I searched for, and found a GPS that was tossed from the impact zone.  While I was there, I captured a sequence of how launches are supposed to happen.

I waddled around the flight park for the rest of the day before joining a large group for dinner and then an uncomfortable ride home.  To make matters worse, it turned out to be a good flying day.  Jon flew from Morningside to the coast, about 90 miles (145 km) away.  I got to look at pictures and track logs as I waited in doctor's offices the following Monday and Tuesday.  Sigh.

I have spent many hours trying to understand what happened so I can avoid doing that again.

Launch upper right, landing 1/3 from right edge along the bottom (Photo by David Park)

First, the objective observations.  I landed directly below launch.  The keel of the glider was pointing about 20 degrees to the left of the intended course line (e.g., inline with launch).  Speaking of the keel, the front of the keel was smashed and peeled open.  Both leading edges were damaged at the nose but the nose plates were not.  The left rear and forward leading edges where sheared by the retaining bolt, i.e., the former small hole was now several inches (~7 cm) long.  Both down tubes (uprights) were severely bent but the base bar was fine.  Aside from a tiny rip in the sail where the nose batten pushed out the rear of its pocket, there was no damage or even scuffs to the sail.

The helmet visor was deeply scratched and the front inner lining crushed.  I had a matching bruise, abrasion, and bleeding above the bridge of my nose that matched the indent in the helmet liner.  I had sharp pain in my left wrist when moved.  (Later diagnosed as permanently damaged cartilage).  I had a bruised and swelling left elbow.  (Subsided in about a week).  I had an extensive bruise and surface abrasion above the knee on my right leg that quickly swelled and was painful.  (Swelling and damage was extensive enough that it created a compartment of dead muscle across the top my leg that has not regrown and probably never will).  The most painful injury was to my left knee.  It burned and quickly swelled but seemed to function properly.  (Orthopedist confirmed knee was sound, but suspected a destroyed or damaged bursa that cushions the knee.  A few days later, the knee was grotesquely swollen and I had a large pail of fluid drained.  The pain slowly subsided over several months).  Although not painful, the most concerning injury were the flashes of light in my left eye whenever I quickly shifted my view.  (Ophthalmologist said the sac that contains the fluid in the eye had pulled from the retina, but that the retina itself was not torn.  Predicted flashes would fade in a month, but it was more than six months).

I'm fairly certain the damage to my legs were from hitting the narrow back side of the carbon airfoil base bar.  It also seems reasonable to assume that the nose of the glider struck the ground with gusto.  There are at least three scenarios of what parts hit what and when, but I don't have enough information or knowlege to solve that part of the mystery.  I'm just glad the damage to me wasn't worse; it easily could have been.

Aside from the unusual calm wind in the valley on a breezy day around noon on a summer day, the tandem pilot Mark encountered unusually strong and widespread lift on the other side of the valley at roughly the same time I attempted to launch.  Also at that time another pilot was dealing with an 'interesting' landing caused by unexpected turbulence.

I successfully launched that particular glider in nil wind from that launch a few weeks earlier in front of a crowd of critical observers.  They offered no suggested improvements even when asked.  So at least on one particular day I was able to acceptably launch that glider in no wind.

That's the end of the relatively objective information.  No one, aside from me, saw the failed launch.  Here is my recollection of what happened.  I know very well that personal recall, reconstruction, and interpretation is flawed, so treat it accordingly.

I believe the nose angle was correct, or at least not high.  I distinctly remember the glider still being on my arms as I ran off the ramp.  If the nose were too high I would have felt the drag of the glider and it would have probably lifted off my arms.

I had been told that my launch strides are too fast and short.  I did not interpret their comments as my launch was too slow but that my style is unconventional or that I might be able to run faster.  I had been slowing increasing my stride but this wasn't the first time I worked on that.  However, it might have influenced the launch.

I was attentive, but not nervous.  I carefully watched the signs of wind speed and direction.  I looked for "leading signs" of upcoming changes.  I have had many many flights off this launch in a wide variety of gliders and conditions.  I don't think I was complacent, but maybe I was.

I remember trying to pull-in and then moments later trying to push-out before impact and not feeling any resistance from the wing.  I have never felt that total "absence" of feedback before while launching.  The closest feeling is probably "going over the falls" at the downward edge of a strong thermal.

I knew even while taking my last step that the wing wasn't flying.  I remember trying to rotate the nose down but nothing aerodynamically happened.  I knew I was falling.

After way too much contemplating, I have reached an uneasy conclusion that 1) I had a smaller safety margin around my no-wind launches than I previously thought, and 2) I am not as good at reading local weather phenomenon as I previously thought.

I think a mass of air that baked all morning trapped under a low level shear layer finally lifted off as I waited at launch.  The rising air mixed and entrained the higher wind above and it curled down the backside of the thermal creating a large area of air flowing down the hill and into the valley.  The lull I chose to launch into was probably the downwash from the thermal.  (A minute or two later the wind was blowing in at 15 mph (24 kph) after being calm all morning).

I also think I needed to either not launch or get the glider going faster to maintain a safe airspeed buffer.  How much speed is really required and how much extra is needed to remain relatively safe?  That is a topic for a future post, but seeking the answer to this question has lead to many discussions, measurements, hypotheses, and testing.  Jeff Curtis has taken measurements of many of our local launches, JJ Cote has gathered measurements on sprinting speeds, and Steve Pearson suggested a model of the launch process that helps tease apart some answers.

One final word about this failure to aviate.  I'm a lifetime addict, so this mistake gets my attention but doesn't dampen my passion.  However, I have to admit, it has been hard to reconcile the hard fall to the ground with the deep faith that we will fly when running off a cliff with a glider.  It reminded me that I didn't always have that faith.  It lets me peer back in time to see hang-gliding as a non-pilot, which at one time, was me.

Wednesday, June 05, 2013

Best Laid Plans of Mice and Men

The car was packed and ready for the East Coast Championship at Highland Aerosports last Saturday morning when a nasty flu struck without warning.  I watched my one chance for competition flying fade away as I suffered both physically and emotionally.  Since it was raining at Highland, I consoled myself by thinking I could leave the following morning and not miss anything.  I had the same depressing internal conversation again on Sunday and Monday morning.  Alas, it wasn't meant to be.

I started feeling a bit better by Tuesday evening so when Peter called on Wednesday morning I was ready for some consolation flying at Morningside Flight Park even if not fully recovered.

I almost sank out after releasing from tow before finding a climb at the end of the runway.  The climb was slow, but gave me plenty of time to keep an eye on Peter far above.

Peter (tiny spec near the center)

I also studied the weather system that soaked most of the eastern seaboard for several days pulling away to the east.

Peter was still waiting when I topped out and stayed behind as I headed upwind to the northwest for another long climb.

Morningside (lower center)

Claremont (from 1800 m / 6000 ft)

After flying around Claremont, I wondered back towards Morningside only to find that everyone else had landed.

As I slowly lost altitude gliding around, I hosted my own little pity party; whining to myself about how I just missed my only chance at a comp this year.  I glided off most of my altitude but didn't want to land just yet.  I found a tiny weak climb over Morningside (0.15 m/s, 30 fpm) that delayed the inevitable.  It was so buttery smooth, I rested by chin on the base bar for most of the climb.

The slow lazy climb gave me enough time to let go of my plans to race across the sky and enjoy the peaceful reflective day I was experiencing.  Such are the best laid plans of mice and men.

Flights: 1, Duration: 2:17