Location: Mt Zion, Golden Colorado
Pilot: Mark Henline
Wing: Sport 2C 155
Time: Approximately 3:30pm
Conditions: Cold Front N-NNE 15-20 mph
Sam and I finally had a chance to watch the video from the on board camera Mark was using that day. We also inspected the glider to be sure there wasn't a problem with it. Joining us was also an investigator from the NTSB who was a friend of Mark's wife Peggy. His experience with these types of events was instrumental and we thank him.
The initial push from the front hit with a lot of energy. Gust to 44 according to the wind talker. As per a normal cold push we like to let them settle before launching. Once the upstream weather stations started reporting NNE in the 15 range we prepared for launching. I was first off climbing slowly in the strong smooth lift until I was 1000 over then headed for the towers. Kim followed soon after. Mark was next up, I didn't see it so I will describe the video.
He launched from the crows nest above the PG launch area as this takes a north wind nicely. As he hike his glider up Sam offered help and he refused it. His ground handling skills were fine for those conditions. He flew slowly to the north point climbing the whole time. During this time he zipped up his harness and pulled a little VG. As he reached the north point he banked an easy right turn and headed south. At this time he is about the height of the top of the hill. There is a slight east arc to his flight path, but once he gets to the south launch parking area he banks a left turn and heads back north as if to get back to the windward side of the hill. He pulls the rest of the VG cord and heads a course a little NNW putting him even closer to the hill. Up until now he has put very few control inputs in indicating smooth air which is congruent with what Kim and I have been experiencing. But as his course is a little closer to the hill he gets his first pop of turbulence. This forces him into an uncontrolled descending left turn just north of the south launch parking area. He gives an input to counter the turn but given the full VG, steepness of the turn, and the turbulent air he was in it did no good. It seems he realizes this and commits to the turn. 3/4 The way around his turn now facing NE he makes a hard counter to the turn even swinging his feet to the outside of the control frame to no avail. At this point he looks at and grabs his VG line releasing about half of it before getting both hands on the base tube. Now at 75 feet facing SW he looks south between the cars and hill for an out, but cannot get the wing out of the steep bank. At this point the left wing tip about 3 feet from the end strikes the Jefferson County rangers truck breaking the leading edge and starts the inevitable rotation into the ground.
Given the information we have I think it is safe to assume that rotor was the cause of Marks accident. Once Mark turned south and past the south point he put himself in the lee side of the hill and south point. Susceptible to both rotor and wrap. Keep in mind as the wind speed doubles it's force quadruples. At 15-20 that rotor had lots of energy and was going to disturb a lot of air for a good ways behind the hill.
Mark was a kind and generous person. He would want us to learn and grow from this. Please do so
Rest in Peace Mark we will miss you