Monday, February 15, 2016

Learning from Simulation - Week 4 Mifflin ridge task


Each winter season, I organize a group of folks at Harris Hill to fly together in what we call "Flight Night".  We're into week 4 of the season and I thought I'd post about some things I learned in a miserable performance this time.

I don’t have very much experience with ridge flying and that’s one of the reasons I wanted to include a task with Mifflin, PA in our online flying.

The task was pretty straightforward up the ridge to the first turn point at sawmill, then back down the same ridge to Allensville and back to the Finish line at Mifflin County Airport.  There were two twists.  The first was the Allensville turn point was across the valley - into the wind.  The second was the finish height was 5,000 feet.  Even though I set up the task, I caused myself trouble in both cases. 

Leg 1

The start and first turn point to sawmill went smoothly.  On a ridge task, the lower you fly, the faster you can go, which can be very disconcerting if you’ve never done it.  The key here is to keep a plan in mind at all times as you move along the ridge.  That usually translates into the maxim that “speed is life”.  If you have speed, you have options.  You can quickly pull up, put a reasonable amount of altitude between you and the ridge and turn upwind, fly out into the valley and land.  I flew along at between 100 and 110 knots to the turn point and made it without too much trouble.

Leg 2

Returning along the same ridge, I noticed after about the halfway point that the lift was a bit weaker as I approached the second turn point.  Checking the wind on the PDA, it was down to around 13-15knots, which is indeed weaker.  I had to fly lower to maintain 100knots and maintain altitude.  I was closing on Tom Hogrefe at this point and was in full chase mode.  

Here’s where my problems began.  The Allensville turn point is ACROSS the valley, which means I had to fly into the wind to get to it.  That slows ground speed and requires altitude.  How high does one need to be to get to the other side of the valley, tag the turn point, and get back?

I didn’t really have a mental math model to do this.  Knowing that the turn point was not at the top of the peak across the valley, I wanted to fly to it, then use the tailwind to fly back to the ridge, then pick up that ridge again and make it to the finish line.  I looked at the PDA and it said I had the turn point made by just a bit.  I’d already made the mistake of not stopping to thermal about a mile back when I encountered good lift on the ridge as I flew under a cloud.  I turned back to that cloud, but as I looked, it was beginning to die.

The First Stupid Thing I Did

That’s when I did something pretty stupid.  I circled in the thermal near the ridge.  I was above ridge height, but as I turned onto the downwind side of the circle (towards the ridge) I re-learned something that I’d been told - NEVER CIRCLE IN A THERMAL NEAR RIDGE HEIGHT.  It only takes a brief pass through sink and you’ll slam into the ridge.  This has caught many real life ridge pilots. 

I was lucky.  Period.  I made the circle, realizing my error, then flew a figure 8 ALWAYS TURNING AWAY FROM THE RIDGE to sort of ‘elevator’ myself up in the lift.  Turns out the cloud was dying and the lift wasn’t great.  At that point, the PDA showed me making the turn point with a bit of altitude to spare, so, impatiently, I headed across the valley.

The Second Stupid Thing I Did

I arrived with far less altitude than I should have.  In real life, I’m sure I would have turned back to the ridge behind and waited for a good thermal to come along.  In the simulator I didn’t do that and this is a good point to make about simulated flying - you need to distinguish between what your limits are in real life and what you sort of science experiment you've decided to conduct in the simulator.  At this point, I noted to myself that I was departing from my real life decision making.  I would normally have ended my real life flight right here.

I pressed on as I could see the turn point was close, but learned something - it was still further up the ridge than I was comfortable with.  There were plenty of fields around for landing, but I hadn’t really scoped them out on the way across.  Another bad decision on my part.  At that point, I was really flying behind the glider, not ahead of it.

I did make the turn point a few hundred feet above the ridge and turned back across the valley but Condor doesn't simulate the sink on the backside of a ridge and I'm certain that would have sunk me for real.  Again, I'd already noted that I was now conducting a science experiment, not a real life flight.

Finally, my brain got in gear to plan for contingencies.  I knew with a strong tailwind I’d be back pretty quickly but would be about 1/2 way up the ridge.  I sidled along the ridge and had a plan to land immediately in the valley if I couldn’t find the lift I needed.  I had my eye on a field as  I passed over it and found the lift.  I kept my speed up climbing slower than I wanted because I needed to keep my speed.  I found lift and was pretty quickly up the ridge to the top.  At this point, I need to emphasize that my flight so far had relied on LUCK, not planning.  It was going to get worse.

The Third Stupid Thing I Did

Fairly quickly, I was back to Mifflin County airport.  Knowing that the finish line was over the airport, I left at ridge height planning to finish and if I needed to land, the airport would be right underneath me.  As I approached the finish line I realized that it had a MINIMUM FINISH HEIGHT.  I’d failed to plan for this!  So here’s the situation:  I’m in the middle of the valley, too low to reasonably go back to the ridge and I NEED A THERMAL to finish.  I tried a nearby cloud, but got nothing.  I turned back to the airport and thought I’d try a cloud on the other side but as I flew downwind, realized I really needed to stop soaring and start landing instead.  So, I did.  No task finish.

What can I learn from this flight?

1.  I should plan further ahead.  I knew I was going to have to transition across the valley and should have kept an eye on possible thermals EARLIER than I did.  When I turned back to catch one I’d flown through, I was already behind on my decision making.  I made things worse by deciding I had enough altitude to get across and back when I really needed at least another 500 feet to do so comfortably.  Upwind transitions to another ridge line are tricky - I know this.  Now, I have no excuse for making the same mistake again.

2.  I got behind in a risky transition and return to the ridge.  I remained behind by not checking the finish height.  That was just poor decision making and caused me to effectively land out and not finish the task.

3.  The whole chain of mistakes was set off by not being patient enough to find a real thermal to climb off the ridge before crossing the valley.  Going fast is sometimes also about being patient.

I’m worried about my ability to fly at a place like Mifflin.  The mistakes I made were ones I’d read about and the solutions are known.  Worse, I committed a cardinal sin by thermaling at ridge height.  In real life, that could cost me a lot more than time.

This flight showed both the value of simulation and the pitfalls.  There’s no ‘gut-check’ in the sim-world.  In real life, I would probably be more careful, but if that’s true, then it’s an issue with simulation.  It’s not that it breeds overconfidence, it’s just that the consequences don’t affect your decision-making as directly as they do in real life.  Many times I read or have been advised that “You just have to go.  Just go.”  But, a lot of pilots don’t do that because they are afraid of landing out.  It’s presented as a concern for risk that you have to manage.  This was the opposite - in “Just going” without that real-life filter, you are aren’t flying like you do in real life.

In any case, I learned a lot in this flight and being able to analyze my mistakes will help me in real life.  Putting aside the non-reality simulation issue, I can still learn lessons I can apply to my real life flying.

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