12-13-20 | The Early Bird Catches the Worm

Sunday seemed an unspectacular day to go soaring. Strong westerly winds, low boundary layer, maybe even overcast clouds. No ridge, no thermals. Evidently no one was excited to come out until it became labelled a “training day”, with instruction flights offered to complete Bronze Badges and check-flights.

Allen, Guido, and Tommy arrived at 10am, ready to get the gliders ready and go fly. Instead, the airport was draped with a heavy fog. The soup was so thick that from the Cow you couldn’t see 508, several glider tiedowns away! Nonetheless, Guido had the Cow perfectly prepared, ready to be brought out to the line to go fly.

The fog refused to lift for awhile, so I gave Allen and Guido some things to work on. Guido completed his Bronze Badge written test while Allen worked on his long awaited Pilatus B-4 check-out. 

Closer to 11, Guido comes back smiling with his test complete and I ran out things to say to Allen with respect to the Pilatus. However, looking up we saw patches of blue. And with Allen sitting in the Pilatus and Guido standing nearby, I asked the guys what they thought about the soaring weather. While they scoffed at the thermals conditions and the wind angle for ridge soaring, I noted what about wave? With the low boundary layer and smooth, stable winds, there’s got to be wave around somewhere today.

Only moments later, we felt the sun starting to bake our shoulders and saw the Pawnee and 182 trotting over to the runway to take quick flights. Allen brought the Pilatus over to the runway, strapped in and ready to go fly while the wind was still manageable in the morning. Shortly after 11, he did a beautiful takeoff and tow, his first in this ship. Guido and I strapped in to give it a go in the Cow.

By now, the wind was rip roaring down the runway. Once over the treeline, Guido was working hard to keep the 2-33 under control. Perhaps a more apt name for the glider would have been Raging Bull rather than Mad Cow! I sat in the back, enjoying the show, noting that the air was considerably more turbulent that would be expected with stable, SW winds.

This is probably rotor!

We released at 2,900ft MSL in lift over the powerlines, halfway to the power grid by the Lower Reservoir. I promptly took control, turned into the wind and raised the nose as high as I could. We hovered at 40mph, climbing at 3-4 knots in the rotor. At about 3,500ft, we transitioned into smooth air.

We found wave!

Guido was ecstatic. I gave him the controls and coached him through the adjustments to make to stay in the lift. With no GPS, it was tricky to remain perfectly positioned in the lift. Instead, we used a known error method, slowly walking forward in the wave until it weakened, and then transitioning back. Similar deal with lateral position; slowly moving right until it weakened and then adjusting back left. We did this for almost an hour, climbing up to 4,500ft on a day that seemed the antithesis of “soarable”.

Meanwhile, Allen took a second tow in the Pilatus and also found the wave. He climbed up to 5,600ft, spending 1.2 hours in the wave until the conditions cycled out and the wave petered out.

While there were wave clouds later in the day and some rotor around, folks couldn’t connect with any more wave. My guess is that the short-lived wave Allen, Guido, and I found was created by our ridge. Despite the terrible wind angle, the air still dropped behind the mountain and bounced accordingly. With the fog in the morning, fully stable airmass, and strong wind conditions, we found as close to classic mountain wave conditions as could exist on the East Coast.

Later in the day, ACA members completed a total of 14 tows; a very successful December day indeed! I did five instructional flights, with Guido, Joe Fenske, Allen, and Oleg. There was a gorgeous sunset, highlighting some wave clouds hovering off in the distance.

11-14-20 | Trouble with the Troopers

Sometimes adventures in soaring take an unexpected turn. Considering that the last time I landed out from Blairstown was around two years ago, the concept of visiting a farm felt like a vague possibility; something that happens to other glider pilots, but not me. And driving out to the airport with Jen, my thoughts were more centered around flying with her and two other pilots in the club two-seaters on this gentle, autumn soaring day rather than heavy duty soaring exploits. A good day for many folks to come out, do some training, stay current and maybe soar on a couple afternoon thermals.

My morning started early, first flying with Anthony in the club Grob. We took a tow to the ridge, discussed situational awareness, ridge testing, and the arrival path back to the airport. Even this early in the morning there were some workable thermals near the airport and we extended our flight accordingly. Anthony did a great job, followed by another very nice landing! Afterward, Guido had the 2-33 all ready to go for my next flight and I took up a prospective member in the 2-33. And after this quick flight, Jen was up next for her introduction to the 2-33, having previously had three luxurious flights in the Grob Twin Astir.

She had considerably more trepidation getting into this old tin can wrapped in fabric nicknamed the Mad Cow. Or maybe it was that a couple weeks ago I was the one who pointed out a rusted rib on the horizontal stabilizer and grounded the glider. In any case, when the rope hooked on and we went on our way to the turbulent tow, she was content to simply hang on and watch. After we released, the wind noise died down and the glider settled into the gentle breeze. Jen took a couple deep breaths and took the controls, getting a feel for the attitude and turning characteristics of the Cow. As we headed over the town, she found a strong thermal and I prompted her to turn, turn, turn! Jen wrapped the glider into a nice, stable turn, climbing up and up at a steady 2-4 knots. Topping out at 4,500ft, she headed to another cloud and found another nice climb, and with the same great piloting climbed 600ft higher. Figuring that would do after 40 minutes of great soaring, we headed back to the airport and landed.

Seeing that the soaring conditions were solid, I decided to take the Duckhawk on an afternoon romp. However, by the time I released over the ridge, it was clear that the conditions were softening up. Nonetheless, I connected with a reasonable blue thermal by the campground and climbed up to 4000ft. Looking ahead, there were clouds in Pennsylvania and I headed over to find turbulent, but reasonably organized lift. These clouds were nicely lined up in a street over to the Pocono plateau, my perennial playground. Finding consistent lift between 4-5000ft, I was doing better going straight and dolphining than trying to circle in this narrow, tricky lift.

Going 40 miles upwind worked great and it was not even that much after 2pm! I always enjoy trips into the wind as they are great practice and make it easy to get back. All you need to do is find a weak thermal, work your way up as you drift downwind and you’re quickly back in glide of your starting location. However, to use a Fernando Silva expression, I got a little “frisky” and was tempted to keep going a little farther before turning around. There was a nice street heading off the Berwick nuclear powerplant, my favorite thermal, and I was tempted to cut across and pick it up.

It turned out I chose to go a thermal too far.

Making the transition over, I found the expected strong sink. However, once under the clouds, I did not find the expected lift! And at this stage, I was surprised to find myself seriously contemplating that this might not work after all. I had an airport in glide downwind of me, but this would near certainly result in a landout. Looking ahead, I could escape into the valley toward a beautiful hay field. Moreover, there were clouds nicely lined up along the way, suggesting that this might work to get me out of trouble.

I’ve dug myself out of worse.

And so I headed over toward the hay field, trying one wisp, and another, and another. Nada. The wind lined up straight up the valley. Down to 1000ft abeam of the field and I felt a little bit of lift. Working this thermal only served to slow down my descent. I stared intently at the field, trying to judge its slope; better not screw that up with such a slippery glider!

Down to 600ft and the thermal picked up. But by this time, I was positioned downwind of the field, and I was drifting faster in the 12 knot wind than I was climbing. Time to knock it off.

Gear lever extended, button depressed, and the electric gear whirring down. Flaps switched into manual, extended to 20 degrees. Airbrakes all the way open; time to get on glide slope. Don’t mess this up, the Duckhawk will easily overshoot the field if you turn too soon. Extending the glide on base leg, followed by a steep turn, yawstring perfectly straight. Now set up with half spoiler on short final. Airspeed right on 50 knots, aimed square at the high treeline short of the field. Tuck it in as close as you can, as close as you can, full airbrakes! Nose over the trees and a hard flare over the field. In ground effect now, time to dump the flaps! Holding if off, holding it off, touch down! Hard on the wheelbrake, stopping as fast as I can without nosing over.

After the glider stopped, the variometer whirred a flat tone. I shut it off, and everything was silent. This is always the most magical moment, for after some of the most exciting flying you can do in a sailplane, you find yourself in a new place and time abruptly stops. I got out of the glider and took stock of my new surroundings. Looking ahead there was a deserted farmhouse and the cut hay gently bent over in the mild breeze.

I was very pleased with my field and my landing. For the past several months I’ve prepared myself for the possibility of landing in a field requiring clearing an obstacle. The Duckhawk is very unforgiving of extra energy on approach thanks to its only adequate airbrakes, which is a big issue when clearing a treeline. I consulted Bill Thar on the technique, practiced it in the simulator, and finally did such a landing at Blairstown airport. I calculated that I should be able to land the glider in a 1300ft long field, figuring I could get it stopped in 1000ft without resorting to ground looping or nosing over. I used up 950ft of the field, with about 300ft of that being ground roll. It was good to see that my preparation worked out flawlessly.

I called back to Blairstown for a retrieve crew. Since Jen had not driven my truck before, let alone with a trailer, I requested that someone else join her on the adventure. Bill Thar managed to convince Steve Beer to go, although Jonathan cajoled Jen to do the driving. She overcame her second bout of trepidation and hit the road behind the wheel of the truck!

In the meantime, I prepped the glider for disassembly and went for a hike to try to find the landowners. I must have been a sight to behold, dressed in my winter coveralls, wires hanging out all over the place, with my 10 liter Camelbak swinging over my shoulder. As I walked up the lane, I noticed that each dense tree had a “No Trespassing” sign stapled to it. And then I found a chain link fence with locks blocking the road.

Upon closer inspection, I found that the chain was mounted to the tree with open nails. With little effort I managed to take it down, eliminating this possible obstacle for my ground crew. I promptly put it back up, in case anyone went up the road before me. However, I got the message; I was going to endeavor to find the landowners before heading back up this road.

Another half mile later and I reach an intersection to find some houses and civilization. Seeing a gal on a tractor working her lawn, I waved my hand to flag her down. Despite my garb making me look something between an astronaut and a bum, I succeeded in encouraging her to approach me. I explained my predicament as a downed glider pilot and asked for her assistance to find the landowners of the field. Her husband quickly showed up and also took great interest to this unusual situation. They invited me into their house for a cup of coffee, taking great pleasure in sharing stories of this sleepy town, inquiring about my soaring exploits, and my work as a PhD student studying neuroscience. The time waiting for my crew passed by quickly.

Her husband made some calls, but had no luck finding the landowner. When Steve and Jen arrived, I invited my new friends to come and see the glider come apart. We went up the driveway, took down the chain link fence and promptly arrived at the Duckhawk. This retrieve was going so well, there was even enough sun on this short November day to take the glider apart with some daylight to spare!

At this point, I was a little surprised to note that my friends did not come to the glider. As it turned out, the caretaker of the land was taking his dog out for a walk and saw the wayward vehicles turning into his field. He intercepted his neighbors, who apparently were doing their darnedest to express the good and friendly character of us glider pilots and our friends. Nonetheless, with the glider packed up, sun setting to the west, and us heading toward the exit of the field, we were met with the irate caretaker and sensed there was going to be some trouble after all.

Further, as I walked out to meet him and his wife, I saw a state trooper driving up the driveway. Goodness gracious, here we go.

The field’s caretaker seemed most perturbed by the fact that his chain link fence proved not to be a barrier at all. I expressed my deep condolences for all the fuss, my yeomen’s effort at trying to find him or the landowners and how the field, glider, and my personal body were perfectly fine. A little while later he seemed to calm down, happier that “everyone and everything is safe”, leaving me to deal with the state trooper, firefighters, and ambulance who all showed up at the scene of the “plane crash”.

I refer to such occurrences as the circus showing up. Everyone comes to gawk at the glider, happy to have experienced the most exciting thing to happen at this town in the last decade. The state trooper had to dot all the i’s and cross all the t’s, insisting that he had to get a hold of the FAA. I told him go for it, my pleasure! And we sat around for ages, waiting for him to be satisfied.

An hour and a half later, I finally had enough and started calling up my friends, instructors, and DPE to see if anyone can get a hold of a person at the Allentown FSDO so the state trooper would finally let us be free. Right as Randy Rickert was dialing up his FAA contacts, the trooper informed me that I would receive a call from the FAA soon and let us be on our way. Steve, Jen, and I bolted out of the field.

After eating dinner at a local diner, we headed back to Blairstown, arriving a little after 8pm. Steve was in great spirits, thanking me for the opportunity to get to go on a retrieve! We dropped off the trailer, took a moment to look up at the beautiful stars. And then Jen and I headed back to Philadelphia.

There were many surprises on my Saturday adventure. But perhaps the most surprising thing was that Jen did not express an immediate urge to dump me after subjecting her to a) Getting up early in the morning, b) Flying an aircraft that seems destined to fall apart, c) On the drop of a hat, driving a scary vehicle with a 25 ft long trailer, and d) Arriving back home at an ungodly hour.

Instead, she said how exciting it was to a) Spend a day at a beautiful place, b) Get to fly a freakin’ glider, c) Challenge herself to do new things, and d) Have the excitement of going on an adventure, seeing a glider retrieve and having the amusement of watching me deftly deal with law enforcement. And how she’d love to do it again next time!

She’s a keeper!


Thanks a million Steve Beer, Jen, Jonathan, and Bill Thar for helping me out on this retrieve. Thanks Rick, Randy, and Erik for assisting me with the authorities. Thanks Tommy and Andrzej for towing! You guys are the best!

See the flight here.

10-31-20 | Trick or Treat?

On this frigid Halloween, many youngsters were getting their costumes ready for a Saturday extravaganza. Houses were decorated with scary dragons, ghosts, and rotting pumpkins carved into contorted visages. In this odd American tradition, it becomes socially acceptable for children to take candy from strange people in the dark. And if you were to chart average blood sugar levels among most kids, they would look like a stock that suddenly rises, crashes, and results in wailing tantrums on the floor.

I never understood this tradition. Perhaps it never rubbed off on me because I was the one tasked with giving out the candy rather than the one dressing up and soliciting it. Or perhaps it was that time I was coerced to wear a crocodile onesie to take part in a Peter Pan themed Halloween party. No good things ever occurred to me on October 31st.

So on this Halloween, I was more than happy to be on the road to Blairstown Airport. My thoughts were not on the prospect of satisfying sugar cravings, but looking up at the sky and daydreaming about flying. Besides, I had enough to be scared about this Halloween. Skyvector indicated a complex set of restricted airspaces (TFRs) between Trenton, NJ and Reading, PA due to Trump furiously campaigning in the final days before the election. And there would be no worse Halloween trick than for me to be on the receiving end of a United States F-16 screaming across my nose, with nasty words to say to me on 121.5.

No, it would be much better if it were for me to play the tricks, leaving some poor and confused radar operator wondering as to how a glider squawking 1202 was staying airborne for hours, patrolling the outskirts of the restricted airspace. With the intention to fly as far as possible given the weather and airspace constraints, I planned to fly on the north edge of the Reading TFR and then maybe into the valley south once the Trenton TFR expired at 2:30pm local time. To cover my bases, I called WX-BRIEF to receive the most up to date information. I could sense the fellow raising his eyebrow upon hearing my plan to fly a glider to Beltzville Airport.

My day started early as Guido and Anthony Erlinger asked to receive some morning instruction in the club Grob, nicknamed Greta. Having completed my Flight Instructor rating the previous week, I was happy to oblige. Guido arrived early and got the battery and golf cart ready while I took a trip to the hangar to bring out the Duckhawk trailer.

Upon arriving on the airfield, I was surprised to see all of the grass covered in a white, crusty frost. Guido is a true Italian and evidently not well adapted to the cold. When we started taking the covers off of Greta, he yelped in pain as the frost bit into his bare hands! Unfortunately, our efforts to start early this morning were for naught. With the air so moist, a layer of frost started covering the whole glider. We promptly moved Greta into the sun for deicing while Tommy the towpilot went to the airport cafe to get himself a warm cup of coffee.

At 10am, we were just about ready to start towing and we needed a wingrunner. Anthony arrived as though right on cue and with him on the scene, the show began. With the magnetos clicked on, starter whirring, and the propeller making several jagged jumps, the engine turned over and the Cessna 182 towplane was ready to fly. With the rope hooked up, wings leveled, the slack in the rope taken out, Guido keyed the mic and in a delightful and melodic Italian accent said, “ACA tow-ah-plane, glider is-ah ready to-ah take-ah-off-ah!”

Guido did a wonderful job. We reviewed all of the peculiarities of the club Grob, especially its insatiable hunger for rudder. He flew great, did a bunch of turns, some stalls, and most importantly, had a great landing at the end. Anthony was next and had the good fortune of launching as the soaring day began. We practiced flying the ship, along with some thermalling techniques. After Anthony came back, Guido took the third and final instructional flight of the day, with a quick tow to 1500ft followed by a prompt approach and landing. For this one, I sat in the back and whistled, pretending to be a passenger and letting Guido do all the work. Predictably he did well and ended the short flight with another nice landing. Just before noon, I was released from my instructional duties and was eager to go fly the Duckhawk.

Around this time, Ron Schwartz showed up to say hello. Seeing that he was willing to stick around for extended socializing, I asked whether he would be willing to help me assemble my ship, to which he eagerly agreed. This was probably a mistake on his part as the process was a bit more tortuous than usual. It’s like the Duckhawk wanted to make a point that I don’t fly her often enough by making it that much harder to put her wings on. And then making a fool of me when something wasn’t quite right and I was forced to take one wing off to fix it. With enough consoling and finagling, the bird was assembled and my preflight checklist was complete.

Looking up at the sky, I was surprised to see that the cumulus clouds did not wither away as expected. Instead, the cotton balls were nicely arrayed as far as the eye could see. This was going to be a better day than anticipated!

Launching at 1pm, I released in solid, nicely organized lift. The ship reminded me that it’s been over a month and a half since my last flight, with a couple instances when the wing wanted to drop after pulling a bit too hard in the lift. Backing off a skosh and working up to a little over 4000ft, I felt great and back in business. With honest and reliable lift all around me, it was time to do some exploring.

As I turned southwest bound, I was delighted to see that the clouds were nicely aligned in streets heading right up the valley. Normally the lift is much better over the higher and drier mountains, but today I accepted the usually risky proposition of flying in the lee of the ridge. With the lift so nicely organized and closely spaced, the Duckhawk made easy work of the energy along the way.

It felt like I was flying a 1-26 again. The 1-26 demands your attention as the last five percent of performance are the difference between flying well and ending in a field. With the Duckhawk, you don’t have the same prospect of landing out, but when you work that much harder you feel how much better you are doing. And in this case, the game was staying connected with the thin lift band under the clouds.

What worked well was to drop the nose and consistently fly at 60 knots. And when I’d find a nice bit of lift, to yank hard and dynamic soar the gusts. In the less lifty sections, to cruise at around 70 knots, with 80 knots reserved for sinking air.

The best moments were when the lift was off to one side and I could bank, yank, and pull hard. It felt like I was dropping my talons, gripping the air, and then ripping it out of the sky. The variometer would wail and the altimeter would wind up and up and up. This kind of dynamic soaring probably worked best because in a turn it was possible to maintain 1.5-2 Gs for a longer time, generating that much more momentary thrust.

In what seemed like no time at all, I arrived at Beltzville Airport. My eyes gazed around for other gliders and to my joy, I saw a 2-33 just below and heading away from me. Being too good of an opportunity to pass up, I dropped the nose, sped up to a leisurely 140 knots and said hello the white and red whale of the skies. After turning back, I saw a vintage yellow Ka-4 release in a thermal and gave him a similar greeting. With that, I climbed back up to cloudbase and started my journey back to Blairstown.

The sky just seemed like it was getting better and better, with the clouds aligned in a perfect row. The challenge now was to soar the 32 miles back home without turning at all. My eyes focused on the dark spots in the clouds and I keyed up my body to feel every bit of the air. The flaps clicked and clacked away as I’d make the glider jink, zig, and zag, flowing up and down the swells and rapids in the sky. Only minutes later, I arrived back at Blairstown Airport having hardly lost any altitude at all. And upon seeing Anthony flying in the club 1-26, I used this extra energy to give him a friendly Duckhawk greeting.

Being just after 2:30pm, this was a good moment to take stock of the sky and assess where to go next. Looking to the northeast, the clouds were withering away. Instead, I was eager to follow the nicer clouds nearby on another adventure to the south. Remembering that the Trenton TFR was to expire around that time, it felt that everything was lining up perfectly to head this way. But to be absolutely sure, I decided to contact Allentown Approach on 124.45 and check. And to my horror, Trump was evidently running late and the TFR was still active! Thoroughly annoyed, I doubled back from Hackettstown to wait a little while.

Half an hour later and somewhat listless, I called up Allentown again and requested an update to the airspace situation. And the controller responded, “The TFR has now been terminated.”

I responded, “Did you say that the TFR has not been terminated or has now been terminated?”

With a satisfactory response that the TFR was now no longer a factor, I got excited again, climbed up to cloudbase, and set my sights on Vansant Airport around 30 miles away.

At this point, the thermals were starting to get farther apart, resulting in a more traditional climb and glide style of soaring. Upon entering the thermals, I practiced making better entry turns, finding success entering the lift at 60 knots and making a very steep turn. And after starting the turn, to initiate a stepwise slowdown to 55, 50, and 45 knots, using my speed to adjust my position in the thermal. The tricky bit was making a solid pull to initiate this process, but not pulling so sharply that it would cause the air flow to separate on the wing and make a lot of drag. You need to be really on top of this glider for it to fly most efficiently.

As I crossed the Delaware River, I had Vansant Airport in view, but unfortunately no friends in the sky to fly with. The air was also devoid of any movement and the altimeter unwound enough to cause a bit of concern. Looking ahead, I could see Philadelphia’s skyscrapers beckoning in the distance and sunnier skies above. Several miles beyond Vansant, I dug out from a little above 2000ft above the ground and figured it was high time to make the journey back home.

Being a little after 4pm on a late autumn day, I resolved to be patient and get nice and high before heading back. To my mild frustration, the thermals were poorly organized and kept me struggling along a little while until a solid three knotter got me comfortably up to cloudbase.

The glide computer indicated I only needed another 2000ft to gain to get home, a little over 30 miles away. It was hard for me to believe that the glider could actually make that work. My mental calculations suggested that this was around 7-8 miles per thousand feet and it just felt that this was too good to be true. So after I tanked up with a little extra altitude in the final thermal, the glider surprised me yet again when it sailed on home, perfectly making the glide.

The best part of the day is when the sun starts to set over your shoulder and the valley lights up in a brilliant glow. Looking over toward Bethlehem and Allentown, the landscape looked like a canvas brushed on with warm oranges, reds, and yellows, occasional glittering blue lakes, punctuated by the gentle steam of distant powerplants, and a misty mountain snaking as far as the eye can see. Autumn is a joyous time to fly in the northeast.

With the additional altitude at my disposal, I flew over to my ridge to see if the wind had picked up enough for the ridge lift to work. Upon dropping down to 1700ft MSL, I found that the wind was at 195 degrees and 12 knots. Surprisingly the lift was fairly solid! This enthused me enough to make two shorts laps up and down the local ridge, getting a close up view of the leaves on the trees and the hikers at Mt. Minsi. As much as I enjoyed flying the ridge again, I was also nearly continuously shivering having under-dressed for the cold, having anticipated lower, warmer, and blue conditions. With the temperatures at ridge top not being high enough to warm me up, I called it in after a delightful three and a half hours in the air.

After landing and spending a good thirty minutes thawing my feet and warming up my body, I was ready to take the aircraft apart. Since there were no club members around, I wandered over to the flight school to see if I could find a hapless victim to help me disassemble. First, I set my sights on the younger Kevin who was tying down his 1-26, but then my gaze later to the young kid nearby. He introduced himself as Andreas, turned out to be thirteen years old, and about 18 lessons into his flight training. Bingo!

I brought him over to the Duckhawk and invited him to sit in the cockpit. Comfortably seated, he started asking all sorts of questions about all the instruments, knobs, and dials. Do you really need all this stuff to fly? I chuckled and replied absolutely not! He asked me about the glider’s performance and handling characteristics, how the gear, and flaps work and why everything is the way it is. Twenty minutes later, it became apparent that I was the hapless victim in this bargain! Only when his dad wandered over to let his son know it was time to go home, he hopped out and eagerly gave me a hand taking the wings off.

On the way back to the parking lot, I briefly opened up the club LS-4 trailer and told him that if he kept working hard that someday he would be flying that beautiful ship. And you could see the gears turning in his head as I closed the trailer lid and he raced on home.

Turns out that this Halloween was a treat after all!


Thanks a million Schwartz and Tommy for helping me fly today, you guys are the best!

See my flight here.

08-22-20 | A Tale of Two Airmasses

It was the best of times, it was the worst of times, it was soarable in Pennsylvania, it was miserable in New Jersey, there were cloudstreets, there were 40 mile blue holes, an airmass with strong and high thermals, and another that produced a thunderstorm that nearly wiped out the airport; in short, a memorable day!

I arrived at the airport with no expectations. It was August; hot and humid with a southwesterly wind pumping in air expended from the swelled up swamps of South Carolina.  My sweat accumulated after assembling the glider, completely soaking my clothes, and refused to evaporate. The few clouds triggering over the ridge were hardly much above ridge top. Having not flown the DuckHawk in a little over a month, I was content to simply get airborne and do a couple takeoffs and landings. And if I managed a short soaring flight, heck that would be an accomplishment.

Glancing at the forecast, the Poconos looked promising. Perhaps it would be good enough to poke around in that wonderful high ground? I set a short task up to Lake Wallenpaupack to do a little bit of sightseeing.

Taking off a little after noon, there were still low, scrawny clouds over the ridge. The first climb off tow was a struggle; 10 minutes in a half knot thermal to claw my way up to cloudbase at 3200ft. A short thermal street lined up into the wind, along the ridge. The DuckHawk was much more content flying straight than circling in these weak bubbles.

The line promptly ended at the hang glider launch, hardly ten miles away from the airport. A slow climb took me up to 3800ft and I looked over at the high ground to the northwest. The clouds were slightly higher over East Stroudsburg and the lift was fairly reliable. And heck, with a 50-1 glider, the odds are good that I’ll find something.

Sure enough, there were a couple bubbles along the way to keep inching upwards. Off my right, there was a rain shower; the sucker looked like an enormous billowing cauliflower, with a dark ominous bottom, slowly moving toward the airport. I didn’t think much of it at the time.

Looking dead ahead toward the Poconos plateau though, the sky totally transformed. The clouds formed little cottonball puffs at 6500ft and you could see miles and miles away. Once over the edge of the plateau, I found solid lift and climbed right alongside the clouds!

My flight computer read out that the wind was 300 degree or so; quite different than the 220-250 degree wind in the valley. I discovered that this was a new airmass, bordered by a trough parked right at the very edge of the Poconos. Coupled with the heating of the high ground earlier in the day, it created a steep boundary where the clouds rose thousands of feet. This was going to be cool to explore!

Along the edge of the line, the lift was not all that continuous, although it worked nicely where the clouds hung down like a curtain. And there it was really fun climbing up on the edge of the wispies!

Abeam of Beltzville, the line made a hard left and seemed to lose definition. I suppose it would be fun to poke deeper into PA. Who knows, maybe I could even make it to the Susquehanna River?

Picking up the pace, I found reliable 2-3 knot thermals under honest clouds. Going toward Hazleton, the cloud base dropped off, but no worries; my nose was aimed squared at the Berwick Nuclear Powerplant.

My name for the thermal that comes off the plant is Ol’ Faithful. The steam plumes are often visible from Blairstown, beckoning the wayward glider pilot like a siren to come over and harness its energy. Positioned in the middle of a valley, right by a river, it’s often the only lift within a considerable distance. The resulting thermal is nearly always marked by a cumulus cloud hanging a little lower than the rest; laden with the moisture coming from the stacks, the thermal is always in a hurry to condense into a cloud. And sure enough, there was a solid 3-4 knotter that picked up to a turbulent 5-6 knots near the top. The thermal was so gusty that at one point it nearly spun me out! After a fun rodeo ride, I was back in business at cloudbase.

Heading across Scranton, the Alleghany plateau invited me with beautiful clouds ahead. While I had flown up before, I’ve never directly flown across these imposing mountains. The wind is often times a bit too strong and the thermals are disorganized for many miles. Going into unlandable terrain, higher terrain, and a headwind is a dubious proposition. Most of the time the edge of this plateau acts like a brick wall.

This time, I cleaved into the higher ground without any difficulty, climbing right up to 7000ft. Out yonder, it looked even better!

But as I drove along, I ended down at 4500ft and felt low. There was an airport in comfortable gliding distance ahead, but that piece of property was situated at a daunting 2000ft MSL. Best to tread carefully.

After slowly climbing up and another tricky glide, I finally connected with a solid 2.5 knotter. A little stumbling around here and recentering there wound the averager up to eight knots. Woohoo!

I kept climbing, and climbing, and climbing. At 6000ft, the cloud above me didn’t feel any closer. Neither at 7000ft! Man, what’s going on here? At 8000ft, the thermal was still going and going, just like the energizer bunny.

That sucker topped out at 9,500ft! No wonder the sink was strong before; there were monster thermals around!

My watch inched toward 3:20pm. A pang of doubt crossed my mind; I better start thinking about heading home.

Around that time, the airport was experiencing an epic deluge. The shower I skirted earlier in the day turned into a massive, slow moving thunderstorm. The radar map showed all sorts of pretty colors and orange/red polygons. And then as you gaze at the legend, your eyes widen as you see a tornado warning in effect.

As the billowing cloud crept toward the airport, all the gliders airborne bolted toward the field. The pilots quickly landed, tied down and ran for cover. Those unlucky enough to be still outside when the rain swept in were caught in a torrential downpour. The wind was so strong that the rain came in sideways. This is the kind of the day when rusty stakes, frayed ropes, and creative knots are put to the test.

Meanwhile, I was oblivious to the mayhem back home. My thoughts drifted toward the ease and relaxation of being in the cool, dry air at 9500ft. My cloud was part of a cloudstreet extending ahead of me and it was just too good of an opportunity to pass up. I nosed over and flew up to the Buttonwood Ridge, 20 miles northwest of Williamsport, a good 108 miles from home. Figuring this would do for the day, I turned for home. It was 3:40pm.

Picking up the pace to 90 knots, it now was time to put the pedal to the metal. Better to run back home while the conditions were still working well! Sure enough, the lift remained totally solid over the plateau. Consistent 3-5 knot thermals to 9,000ft, good air in between and a tailwind for good measure too. This was glider pilot heaven!

Abeam of Scranton, 70 miles from home, the clouds ahead lost some of their definition. Off my left, the cloudbase dropped off precipitously.  I tanked up as high as I could; better to be thermalling up here, than down there! This climb took me to within 1000ft of a MC 3 final glide. This would comfortably get me across the whole Pocono plateau and might even do for squeaking it home in a pinch.

Over the next 45 miles, the air flattened out. The day was softening up; boy was I glad to have tanked up! I slowed up and floated in the good air, but there were no solid thermals for a long way.

Looking ahead, I could see Mount Pocono Airport beckoning in the distance, with many clouds still formed along a parallel line to the plateau. Sure enough, the trough line was still working! Beyond these clouds, the air was a hazy blue, devoid of all clouds. It looked like the streets at the edge of the Poconos were pushed into this invisible barrier, with the resultant cloud spewing in all directions; upwards, downwards, and sideways. The tendrils hanging down indicated solid lift was working ahead. I relaxed, knowing that I had it made.

Sure enough, approaching the line there was a good thermal and I easily climbed up for final glide with plenty of height to spare. But these peculiar clouds alongside me were just too tempting to simply bypass. Instead, I turned toward Lake Wallenpaupack and played with the line.

It was so much fun! When the glider sank a bit lower, I’d park my wing in the tendrils and thermalled right up the edge of the cloud. In between the streets, there was some mildly good air serving to extend the glides. This worked very nicely for a lap up and down the line, which was slowly inching its way northwestward. With my watch showing a little past 6pm, it was time to call it a day. After rounding the last cloud, the flight computer showing a MC-3 glide, I turned toward Blairstown Airport, heading into the blue, dead void.

Slowing down to best-glide speed, the air was dead smooth. I let go of the stick, turned the variometer down, and just watched the mass of trees under me, gliding toward the ridge off of my nose, the glider contentedly humming along. The upper reservoir was way off in the distance, slowly inching downwards in my canopy.

I looked down at the twists and turns of the terrain below, the setting sun off my right shoulder, and the clouds dissipating behind me. It was just so peaceful, so much so that it felt odd that the flight should ever end. It seemed like the sailplane will silently sail on forever.

Coming over the airport, the wind sock was dead limp. There was some mist forming off the runway and I lined up to land on 7. Since the original objective of the flight was to perfect my landings in this glider, it felt appropriate to oblige. I lined up over the trees, pushed over and landed short of the mid-field taxiway; a challenge completed!

Getting out of the glider, I was surprised to find the grass to be wet and squishy. Everything was soaked and the airport was totally deserted.

When young Kevin emerged out of the shack, it seemed like he was the sole survivor of an apocalypse. He greeted me with the harrowing tales of the afternoon and later helped me disassemble the glider. Later, a couple stragglers banded together to spend the rest of the evening trading tall tales of exploits in days and years past.

All in the adventure that we call a day at the airport!


What a wonderful day! A day that started with no expectations, yet ended in a 270 mile flight! Blairstown offers such dynamic and wonderful soaring; no matter how long you fly here, there will always be new challenges. Thanks Tommy for towing and Bill Thar for crewing in the morning!

Find my flight log here.

Daniel’s Ridge Commandments

Violate these commandments at your own peril, for the Almighty Ridge will smite those who fail to respect it.

  1. Thou shalt be proficient and prepared to tow in windy conditions (eg: Checklists complete, no loose articles, belted in tight, emergency plan prepared, familiar with tow signals, etc.)
  2. Thou shalt test the ridge with a landing option in glide and your approach planned.
  3. Thou shalt not fly low and slow near a ridge (eg: < 150ft AGL AND < best glide speed).
  4. Thou shalt not drift downwind of the ridge band!
  5. Thou shalt not turn toward the ridge.
  6. Thou shalt s-turn until sufficiently above a ridge (min: 200ft AGL, 400ft better)
  7. Thou shalt turn nose low, coordinated, and with sufficient airspeed (eg: best glide speed).
  8. Thou shalt not fly into a box canyon.
  9. Thou shalt have a landing option in glide and approach planned at every moment when completing a transition to another ridge.
  10. When approaching an unlandable area, thou shalt reassess the conditions and establish your landing options/approaches ahead and behind you.
  11. Thou shalt not fly on the downwind (lee) side of the ridge!
  12. Thou shalt respect the right of way rules: Right wing to the ridge has the right of way.
  13. Thou shalt be proficient and prepared to land in windy conditions. Maintain extra altitude and airspeed during approach/landing. (eg: +200ft above IP, +15-20 knots in the pattern, turn final 100-200ft higher and land long down the runway if practicable.)

And if you’re flying at a site that requires soaring back to your airport:

Thou shalt establish and maintain a minimum margin to return to the airport (eg: Blairstown – 2400ft in a 1-26).


Note that these margins are provided as ballparks and may need to be adjusted for a given ridge site, sailplane, conditions, and the experience of the ridge pilot.

Why Thermal in a Slip? | And the Hazards of Skidding

Experienced soaring pilots usually advise thermalling in a slip. Dick Johnson in the October 2004 issue of Soaring magazine provides an excellent technical explanation for how and why to use this technique.

The bottom line is that a turn requires a combination of pitch, bank, and yaw to maintain a stable configuration. And it requires some compromises to achieve the most efficient combination.

If you thermal fully coordinated, you will need to use top aileron to avoid “falling into the turn”. If you slip using top rudder, you will minimize or even eliminate the top aileron. You are compromising by dragging the fuselage through the air stream, while making the wing cleaner.

It seems like some combination of top rudder and top aileron is often most efficient.

Conversely, turning with ANY amount of skid is VERY inefficient. The MORE you skid, the MORE top aileron you need to avoid falling into the turn.

In this case, you are BOTH dragging the fuselage through the air stream AND using quite a bit of aileron to keep the turn stable. This is very bad!

I notice that many pilots thermal with a heavy inside foot, resulting in a skidding turn. Aside from being more spin prone, even a minor skid will be very draggy!

Next, skidding into a turn (leading with the rudder) makes the glider especially spin prone. Initially you rudder into the turn, followed by feeding in back stick and opposite aileron to stabilize the turn. This serves to load up the glider while putting in control inputs that aggravate stalling/entering a spin.

This is especially dangerous in the pattern. Many pilots have a tendency to over-rudder their turns while on approach.

Here is a scenario that can easily result in a stall/spin. A low and slow base leg, followed by an over-ruddered, button-hooking turn.

As you start turning, you use too much rudder. This is followed by pulling back to get the turn established. And finally, feeding in opposite aileron to keep the glider from falling into the turn. This results in the glider departing into an unrecoverable spin.

Building Your Toolbox | Responsibly Developing Your Margins

Many accidents in soaring are while flying cross country, particularly during landouts. Most landout related accidents have little to do with unexpected occurrences in a good field. Instead, they have more to do with the situational awareness, judgment, and decision making of choosing an appropriate field at the right time and selecting the right time to quit soaring and land.

Most pilots get injured or killed in the stall/spin during low thermalling, or a poorly planned approach into the field. Or, neglecting the field selection process until it’s too late and the nearest field is unsuitable due to obstacles, slope, or wires.

I’d like to focus on low thermalling and approach planning. What is extremely disconcerting is that pilots do dangerous things near fields. Dangerous is a relative term; what is unsafe for one pilot is “safe” for someone else with more skill, experience, and practice.

However, what is scary is that pilots who are generally “conservative” near their home airport under the close eye of their fellow club members will often take “chances” while flying cross country.

An explanation for this behavior is that it is an example of loss aversion. Pilots confuse being risk-averse/conservative with simply finding losses being painful. Rather than being conservative with respect to landouts, they simply really really don’t want them to happen due to their inconvenience or feeling embarrassed. And if they find themselves getting lower near a field, they will be MORE tempted to take chances to avoid landing out!

If a pilot is conservative, they will select a good field EARLIER and quit at a HIGHER altitude, rather than taking chances near fields! Instead, a loss averse pilot accepts safety risks to minimize their likelihood of accepting a loss.

To stem this behavior, I suggest developing a toolbox of skills and margins. Think of this like an athlete. You practice at your home court, your gym, your own pool or your personal track. And when you go to a meet, now you put your skills to the test.

Just like you shouldn’t try out a novel swimming technique while competing against other swimmers, you shouldn’t be experimenting with anything you haven’t practiced before while flying cross country. Especially as it relates to safety!!!

The toolbox MUST be built up in controlled conditions. The idea here is that abbreviated patterns, landing techniques, low thermalling, ridge soaring, final glide planning, or anything else should be thought through and practiced beforehand. Here are the steps to building your toolbox:

Think Through the Theory

Especially as it relates to safety skills, there’s a lot of disagreement over what constitutes reasonable judgment and decision making. For the purposes of this discussion, I will discuss choosing margins related to low thermalling, although you can apply this process to all safety related skills.

If you go on RAS, some people will tell you that thermalling below 1000ft AGL is absolutely insane and you should be thrown out of a glider club should you attempt it. Others will tell you that thermalling at 200ft AGL is perfectly A-OK and no one has any business telling them otherwise.

I doubt that there is any sport that has a 500 percent disagreement over what is reasonable and safe!

I have my own thoughts about these margins, but my objective here is not to proselytize. Instead, you should think long and hard about your goals. The closer you get to the edge, the narrower your margins for error and the greater your risk. Come up with a set of approximate numbers and consider the various contexts that you might apply them.

Note that your margins should be built around less than ideal circumstances. In the case of low thermalling, assume that you will be hot, tired, dehydrated, distracted, on the last day of a competition while in contention for placing well, on a somewhat windy day, near a less than ideal landing option.

Don’t assume you will be 100 percent on your game! Give yourself some room for error.

Consult a Respected Mentor

After you have come up with your limits, discuss them with a pilot you trust. They will provide you feedback and give you a sense if you are in the ballpark given your experience level.

One word of caution is to be careful to whom you gravitate towards. If you look at people in a positive light, the spectrum goes from pilots who are more focused on the sporting side of soaring while others are on the recreational side. The alternate perspective is the spectrum goes from “crazy” to “safety conscious”.

The truth is usually more complicated, but the point is to be careful seeking out affirmation of more aggressive minimums from a pilot that has a reputation for being “crazy”. Regardless of your feelings toward your mentor, you should expect opprobrium from a good portion of your flying club should you apply aggressive minimums if you are a beginner.

Practice in Condor

Once you decide what is reasonable and appropriate, practice these skills in Condor. Put yourself in many different situations and see how your margins play out. Practice thermalling low near airports, fields, in windy and turbulent conditions, etc.

Practice breaking your margins. See what happens when you get a little too far away from your field. What happens when you thermal a bit lower than your minimums? What happens when you thermal too slow and enter a single full spin?

Are your margins robust to failure, or do they require perfection from you to work?

The point is to practice every kind of failure you can think of in the simulator before you attempt it in real life.

Build Your Margins Locally

As you soar in gliding distance of your airport, practice your thermalling techniques and slowly build up your margins. Suppose you decide that your thermal minimums are 800ft AGL. On a non-busy, calm day, maybe take that turn in that thermal near the airport.

Practice your techniques in the real world. These margins now form your toolbox for cross country flying.

Applying Your Margins Cross Country

Approach flying cross country like you are performing at an athletic meet. NEVER do anything that you hadn’t practiced before. When you find yourself in a tricky situation, open up your toolbox and responsibly apply your skills/margins.

If the lowest you are comfortable thermalling near the airport is 800ft AGL, then you should NOT thermal lower than that altitude near a field!

If you are uncomfortable making non-standard patterns at your home airport, you should NOT do anything less than a full pattern into a field!

If you are uncomfortable arriving lower than 1500ft AGL at MC 4 to your home airport on a final glide, you should NOT arrive at an unfamiliar airport with any less margin!

If you are uncomfortable flying a weak ridge locally, you should NOT attempt a save on a weak ridge far away from home!


In summary, think through the skills you wish to develop, and practice them in controlled circumstances. Develop your toolbox. Practice, practice, and practice some more!

Note that these margins are elastic and depend on your proficiency. Just because you were comfortable doing something once, doesn’t mean that you can be comfortable doing it in the earlier part of a soaring season. Or ten years later after taking a hiatus from soaring. You must consistently assess and reassess your margins.

Think of cross country flying as going to an athletic meet. You are now performing, not practicing! And when you perform, don’t do anything you haven’t practiced before!

I believe if soaring pilots apply this approach to their soaring, they will be a lot safer.

Bringing It All Together | A Lap Along the Local Ridge

It’s a nice day with moderate wind, perpendicular wind direction, and decent thermals. We had towed over to the ridge, tested out the conditions and dropped down on the trees. We are finally ready to soar along the ridge, having trained all of the key ridge concepts and raring to go!

In this video, we do a simple lap from the Upper Reservoir, to the Delaware Water Gap, up to the Millbrook Powerline, and back to the Upper Reservoir. We discuss the local landmarks along the way and some of they key thoughts that come to mind in various stages of the flight.

If any of the concepts or landmarks are not familiar to you, refer back to their respective videos.

It’s worth noting that when the conditions are working well, ridge soaring *feels easy*. And in a way it is; when a pilot has the foresight and skill to choose the appropriate conditions and stays in the wonderful ridge band, there’s little that can go wrong.

But the training, coaching and the practice is to prepare you for that very reason. When you know the traps, have a plan and have the knowledge to extricate yourself from various situations, you will be able to fly the ridge safely.

And this is why there is about 3 hours worth of explanation and context that goes into a 20 minute video of showing how it works when everything goes right.

Introduction to Ridge Transitions | The Catfish Ridge Jump

The purple line is the flight path. We DO NOT fly in the “No fly zone” as this area is dangerous and the ridge works poorly. Instead, we make our transition from the local ridge to the catfish ridge. We often use the “gully line” to find a thermal and good air to make our crossing.

This segment is a crash course in how to do ridge transitions. We start out with the Catfish Ridge transition as it is the first one that many pilots will encounter in their ridge training. This little offset has all the features of a transition and gives our pilots a great way to practice their transition technique.

Ridge transitions often require a lot of attention in a ridge flight. These are areas where we have to cross from one ridge section to another, often due to the shape or current conditions making a section not work well enough to support the glider. These crossings are “hinge points”, as you are more likely to find sink, or a non-working section of ridge while completing a transition. Many ridge-related landouts are due to transitions going wrong.

When a transition goes wrong, you have to execute a landing very quickly in sporty conditions. A couple seconds here or there could make a big difference in the outcome.

Having extra altitude and margin goes a long way to mitigating the risk.

Situational Awareness

While flying the ridge, you should be completely aware of all the transitions on the ridge you intend to fly. You should recognize that you are approaching a transition point as you are flying the ridge. Next, you should have scouted the landing options at the base of the ridge, should the transition go wrong. You should find them and plan out your approach before you begin the jump.


There are five steps a transition:

Gain altitude (Float up in the ridge band or thermal)

As you approach a transition, it usually pays to slow down early and gain altitude. By working your way up into the higher lift band, you can make the ridge do the work of giving you sufficient altitude, rather than struggling to climb later.

The amount of height you will need depends on the conditions, your experience, and your glider. We often give some numbers for pilots to start out with, such as ~2100ft MSL for the Catfish Ridge transition. When we provide these values, we are giving pilots “the highest common denominator” with respect to altitude. The height that you would make it across assuming you run a bad line with a less favorable wind direction. But with more experience, you can judge the conditions on a day-by-day basis.

Pick your line

A big decision is deciding where you are going to jump off from. The simplest way to do it is to simply find the shortest line; get as high and as close as you can to where you want to go and make a beeline across to the other side. However, this neglects the effect of the air in between. Often transitions will have thermals or energy lines that line up consistently due to local terrain features. It often pays to run “a good line” upwind and maintain higher altitude rather than simply taking the shortest path. Conversely, making a transition in strong sink into a strong headwind will make your altitude evaporate very quickly and you may not make it across.

Probe the air

When you start a transition, you are not immediately committed to going all the way across; you can test out the waters. If the transition is working out well and you are generally maintaining your altitude, that’s good. If you start hitting sink and dropping out, you can still turn around and try again.

Point of no return

There is a point when you can no longer get back to the ridge you started from. You must recognize and acknowledge this point as you do your transitions. Once you have gotten beyond the point of no return, you will either make it across, or land in a field that you have scouted out in case the transition does not work out.

If you have extra altitude and you are going upwind, your point of no return can be delayed quite a while. Downwind jumps will reach this point a lot earlier as you get blown too far downwind to make it back very quickly.

Commit to the transition

This is less the case in small jumps like to the Catfish ridge, but there are instances in large transitions that you get beyond the point of no return and may or may not be able to make it across. This is the case such as if you are trying to do big upwind transition and you are in the middle of the valley, considering whether you have enough energy to safely go over the top of the mountain. During this stage, you are considering your landing options along the way. As you get closer, you decide whether you will want to commit to the transition and continue over the top of the mountain.


Doing Transitions Low

In the videos, we explored how to do transitions by the book and what happens when you do them marginally. As you get lower, factors such as the wind direction can play a significant role as to whether you will make it across or not. If the wind angle is off and you have a significant headwind component, you may have to go a long way into lee sink, headwind and around a corner to find a working section of ridge. You will lose a lot of altitude along the way.

Next, we see how the stages shift based on your margins. If you’re low, you will reach the point of no return sooner. This commits you much earlier and you are taking a greater chance of coming up short and landing in a field.

In sum, a couple hundred feet here or there makes a BIG difference in ridge transitions. Stay ahead of the steps, know your outs, and maintain your margins.

Off-Angle Wind

When the wind angle shifts more than 30 degrees off from perpendicular, the ridge lift becomes less reliable. As a result, we strongly recommend that beginners “stick to the formula”; wind speed 15-25 knots at ridge top, within 30 degrees of perpendicular for the section you are flying. In these conditions, you can generally expect the well-flown ridges to have “robust” ridge lift. This is to say that the ridge lift should be consistent and reliable; few factors can suppress or significantly affect the ridge band.

However, when the wind is outside the formula, this is not to say that the lift shuts off. Instead, there are many more complications that can affect how the ridge band works. Certain sections may work very nicely, while other sections are completely flat. The high part of the band may allow you to float at a moderate speed, whereas the low band may not be working.

With experience, it becomes possible to anticipate these factors. That said, it requires flying on many days, progressively exploring the ridge, and building up your margins. Intermediates may explore these days in the comfort and safety of the local ridge and experts may take advantage of these days going cross country.

While I do not advise beginners to fly on an off-angle ridge, beginners should nonetheless have a sense of what to expect if the wind angle shifts, for instance if the conditions unexpectedly change over the course of the day.

The more off-angle the wind is, the higher off the ridge you have to be.

As the angle shifts, the air becomes violent down on the treetops. There will be a turbulent wash as the wind angles over the mountain. By the time the angle is 45 degrees off, you typically have to be at least 300ft-400ft above the trees for the band to work well. Aside from being turbulent, the lift will typically be disorganized and weaker lower.

The more the angle shifts, the higher you must float along the ridge.

If the wind is on the weaker end of the spectrum (<20 knots) and/or the thermal activity is limited (think overcast above), the high band will get weaker.

If the wind is weak and/or the thermal activity is suppressed, watch out. This will weaken the high/float band. This is a really big problem! The lift band becomes compressed; it becomes only possible to float at best glide speed at 2000ft MSL or so and you cannot get higher or lower. It takes very little for this lift band to weaken to the point where it will no longer sustain you.

If the wind is weak/moderate and/or the thermals are not working well, do not count on an off-angle ridge.

Expect substantial sink when encountering thermals on the ridge.

Watch out for thermal suppression, especially when heading into a quartering headwind. Recognize that you will be approaching the thermals on a cross angle. This means you will need to traverse a long band of sink before you encounter the lift.

If the ridge band is not working well and the thermals are strong, you can easily get flushed down to ridge top. Moreover, this effect worsens as the wind angle increases. For example, if the wind angle on ridge top is 45 degrees off, but the thermal street above angles 55 degrees off at cloudbase, you may traverse 5-10 knot down sink over the course of a half mile! This amount of sink could be enough to knock a glider off a ridge, especially a low performance ship.

Watch your airspeed while down at ridge top.

When going upwind, your ground speed will be very low. However, when you turn downwind, your ground speed will be very high. When heading downwind, it is easy to let yourself get dangerously slow if you are not paying attention. The trees will be flashing by very quickly, giving you the illusion of flying a lot faster than you really are.

Certain ridges are tolerant of an off-angle wind; others are not.

Generally, ridges that are fairly high, straight, have few upwind obstructions, and few issues like gaps, bowls and spurs are more tolerant of an off-angle wind. Conversely, any of these issues will cause a ridge not to work in a given section if the angle is sufficiently off. A ridge with many issues may not work with a wind angle greater than 30 degrees off.

In summary, when the angle shifts beyond suggested tolerances (+- 30 degrees), the conditions become marginal. This makes flying in these conditions an expert endeavor. However, the lift does not necessarily go away. With practice and experience, you may still find a solid working ridge band. And if the conditions unexpectedly shift, you will know what to expect.