Coffin Corner

This cautionary tale is more for cross country pilots flying from Harris Hill. Of course, any local flight can be turned into a cross country flight by a pilot who gets out of glide of the home airport.

Two novice cross country pilots are experiencing their second cross countries together in separate ships. Susan has a Libelle and Cy has a borrowed ASW19. Their previous cross country was to Dansville which they enjoyed on separate soaring occasions. Susan has a glide computer with XCSoar running on a Galaxy Tab A display. A LXNav nano provides the GPS data. The system is portable and she’s practiced with it a bit at home. Cy’s got the full panel mounted ClearNav set up in the ASW19. He used it to go to Dansville and back but hasn’t practiced with it since. Neither pilot could be said to be intimately familiar with their flight computers.

After a fun trip to Binghamton, they are now returning to the Hill looking to achieve final glide. They are over the Newtown Battlefield site near the Hamlet of Lowman, east of Harris Hill. Susan is a 200 ft lower than Cy and they are few miles separated from each other.

Susan has her glide computer programmed with a 1000 ft arrival height and the McCready set at 2.0 which is a pretty flat glide angle as the conditions have been just so-so, most thermals all day indicating 4 knots on the vario needle or less. Her glide computer says she is 850 below glide slope for home so she clearly has to stop to find another thermal before continuing over the City of Elmira.

Cy has his glider computer set with an arrival height of 500 ft above Harris Hill but he doesn’t know it. Someone else flew the glider since his Dansville mission and changed the setting from his intended 1000 ft. He has got McCready 2.0 set also and shows 200 ft “in the green”, i.e., above the glideslope. In fact, he sees that by changing to to McCready 1.0 the margin jumps to almost 400 ft above glide, which seems better yet (?). He continues to Harris Hill.

Susan never finds a thermal and eventually lands without incident in a good, flat field in the valley by Lowman.

Cy crosses the City of Elmira without any problem. He then realizes he’ll need to wiggle right of the TV tower with its guy wires, a fact not accounted for in the glide calculation. No problem - there is a cloud there indicating the presence of lift. He is now over the Harris Hill plateau with its rolling hilltop fields and few landing options. He misses the lift under the cloud and hits only sink. Still good though. The data shows minus 100 ft. In his mind he’ll get back with 900 ft of arrival height. It looks lower than he’s ever seen but he continues. Going forward is the best option now. He is actually quite low, McCready 1.0 with only 400 ft above that. Cy is now in the coffin corner.

Cy is fixated on the south end of the runway now. There is another thermal a little right of course but he is on a beeline. Because he doesn’t deviate for the lift, he hits the sink surrounding the thermal and blows all remaining glide margin. He doesn’t even look at the glide computer anymore. He’s realized it’s not giving him good information. He’s looking toward the runway. The problem is the knoll (where Roy’s house sits) is obscuring the view. He is that low.

Cy flies around the knoll to the right, comes over the trailer storage hangar, swoops up the hill and miraculously plops the -19 on the south end of the runway, rolling about two fuselage lengths. He walks away unscathed but obviously shaken.

Susan’s flight is fictitious, but Cy’s flight more or less really happened at our field.

So, here are a few takeaways.

First, approaching Harris Hill from the east and southeast is different than approaching from the northwest. Arrival height is always paramount for safety and even in a competition where one might skimp on arrival height a little coming from Dansville with fields at the base of the ridge, never skimp on arrival height crossing the plateau.

Second, know your flight computer. Check the final glide settings before each flight. And most importantly know that the flight computer simply provides some information, not answers!

Lastly, know that the valleys surrounding Harris Hill gives the illusion of being higher that you are. Cy would never have felt comfortable with that glide over flat terrain.

Adequate arrival height does two things to keep the pilot safe. It allows for loss of altitude when sink is encountered returning home. And it enables a full pattern back at the field.