Is the 200ft below Min Finish Height Rule Working?

On Tuesday, January 21, 2014 12:46:33 PM UTC-6, Luke Szczepaniak wrote:
A hard deck in a 4 mile radius doesn't resolve the issue, only moves the
problem further away from the airport. The only solution is a hard deck
throughout the task area - but wait... what about mountain sites, that's
OK, we will come up with a separate rule for that when we get there .

Cheers,

Luke


PS: I am not advocating a hard deck throughout the task area.. I am
just trying to demonstrate what happens when we move the responsibility
of flight safety from the PIC to the RC...



I don't want to start this pointless argument, but let's at least get the facts straight.

A hard deck sits over the valley floor. Mountains stick out. A hard deck is defined by SUA files, so varying valley floor is not a problem. There is no technical problem in using hard deck for mountain sites. Yes, the hard deck does nothing about crashing in to mountains or low thermaling over ridges. You'll have to do some PIC work.

A hard deck does the opposite of "move the responsibility of flight safety from the PIC to the RC." Under current rules, when you're at 500 feet, the RC says loudly "come on, thermal away, we give you hundreds of points if you pull it off." Under a hard deck, at 500 feet the RC says "we are not going to bias your decision either way. Thermal out, land, do what's safest. You are PIC. You get the same points no matter what you do."

How you can possibly construe this to be taking "responsibility for flight safety" is beyond me. Think just a little bit.

Again, I do not want to start a hard deck war. Pilots have spoken, and do not want it. But let us not pass around pure silliness on the subject. A hard deck is straightforward to implement in ridge and mountain sites. A hard deck does not tell the pilot what to do, it merely removes the current big point bonus for one decision.

Choose not to have a hard deck because you like winning and losing races at 300 feet, not because of false facts and rumors.

John Cochrane

On Monday, January 20, 2014 10:20:15 PM UTC-5, wrote:


You did not provide a logical reason why this big change (scoring as land out) was made rather then just raising the finish height and leaving gradual penalty.



The point of scoring low finishes as a landout is real simple. When you're deciding "shall I land in the last good field or press on" at MacCready 0 plus 50 feet, it needs to be crystal clear that you will gain nothing by pressing on. This is not safety legislation -- points are off the table, make a good decision, points are the same either way. With a graduated penalty there is always some benefit to pressing on. And complexity. Didn't you guys want simple rules? Try figuring out the points to finish 397 feet low.



It just moves the hard ground down. You used to be scored as a landout -- with none of this mollycoddling graduated penalties -- if you missed the fence by a foot.



Don't think of it as a "penalty." The task is to start below (say) 5000', get inside three turnpoints, and finish no less than (say) 700'. If you didn't do that, you didn't fly the same race as everyone else. In what other sport can you miss the finish line by 200 feet and still get a "finish?" And want more?



John Cochrane

John, you are saying this is not "a safety legislature" then what is it? What was the purpose of this change, more fun?

This rule does not change behavior. If old rules were in effect a pilot would try to make it to the field and he would get there say at 450 feet (safe).

According to the new rule he thinks he can not loose so many points by being scored as land out. So what does he do? He says oh well I am going to try to thermal low on final glide in hope of finding the missing points instead of ending up safely at the field at 450 feet and accepting penalty according the old rules.

This rule creates a bad incentive. You just changed one not so bad situation for much worse.

You just can't fix the world. Smart pilot will think about going home safely to his family a not so smart pilot will take risks no matter what.

Let's not cry out about how bad finishes are in Europe. We already had the 500 feet we did not need any more improvement. What is next? This never ends like it did not end on 500 feet.

Hank Nixon wrote:
I'm unclear by what BZ describes whether he is suggesting raising the top(1000 ft finish with 500 ft landout threshold, or lowering the bottom. Clearly the latter is less safe.

I am not suggesting that the RC lower the bottom but rather raise the top of the “penalty zone”. As I read the RC notes concerning proposed rule changes on the SSA website, it says in part:
Guidance Revised: Setting Minimum Finish Height
This amends the guidance to highlight the need to consider additional factors

The notes suggest to me that the CD has great latitude on setting the MFH depending on the competition site and other considerations. It defines the MFH as “the minimum height for a penalty-free finish.” The notes continue, “Because a valid finish (with a very small penalty) may be up to 200’ below the MFH (to accommodate instrumentation errors),it is this lower height that should be considered when setting the MFH. Thus in the absence of
landability, traffic, or other concerns, the MFH should normally be 700’ AGL at a mile, which
avoids creating a big step in points (landout rather than speed finish) at 300 ft AGL leaves even
the lowest valid finisher with 500’ for a pattern and landing.

I read that is the minimum altitude to avoid a land out is “normally 500’ with a “penalty zone” of 200’ more. I am simply suggesting that the rule could be improved by adding 300’ to the fixed 200’ as a “penalty zone”. That would preserve the accommodation for instrument error and add an additional measure of safety. It would also make the accumulation of penalty points for a slightly low finish more gradual. My suggestion of a 500’ “penalty zone” was just an example. The RC could pick another number if it were more efficacious. The bigger it is the more gradual the accumulation of penalty points would be. The effect is that for a small error in arrival height there is less incentive to attempt a low save. Finding oneself 200’ lower that intended is more likely than being 500’ lower.

On Tuesday, January 21, 2014 3:41:35 PM UTC-8, Bravo Zulu wrote:

"I read that is the minimum altitude to avoid a land out is “normally 500’ with a “penalty zone” of 200’ more. I am simply suggesting that the rule could be improved by adding 300’ to the fixed 200’ as a “penalty zone”. That would preserve the accommodation for instrument error and add an additional measure of safety. It would also make the accumulation of penalty points for a slightly low finish more gradual. My suggestion of a 500’ “penalty zone” was just an example. The RC could pick another number if it were more efficacious. The bigger it is the more gradual the accumulation of penalty points would be. The effect is that for a small error in arrival height there is less incentive to attempt a low save. Finding oneself 200’ lower that intended is more likely than being 500’ lower."


Deep breath. Lots to discuss here.

In the interest of exposing some of the richness of the issues for those of you who are interested enough to dig into the actual details that inform these decisions, here we go.

There are three main objectives for setting rules around finish height and then a bunch of considerations. In rough order of priority:

1) The top objective is to make sure that pilots set up enough altitude buffer to get home without hitting the dirt under most scenarios of unexpected sink, headwind, etc. A decent MFH does this pretty well so long as it includes a penalty that costs more than the speed points lost from stopping to climb in a weak thermal. (Otherwise pilots gain points by ignoring thermals below the break-even climb rate for the penalty gradient). This is the highest order pilot decision - setting up the glide is at the top of the final glide decision chain. The penalty is fundamental - without a penalty structure MFH is practically meaningless. If you want to have all pilots set a 1000' arrival you need around 100-200 points per 1000' at stake to create an incentive in favor of climbing in a weak thermal rather than pressing on.

2) A related, but separate, second objective is to not create a points temptation to go for the finish cylinder at a height from which you cannot safely make the airport - instead of picking a decent field while you have a little altitude. This is mostly a "glide gone wrong" or "glide that was never right" scenario and is a totally different pilot decision from #1. This minimum safe altitude is, as has been pointed out, around 400-500' a mile out, depending on the airport configuration. Therefore, the penalty for 500' or below needs to be around 400 points to get rid of the points incentive to press on. That means you need to spread 400 points of penalty over the difference between MFH and 500 feet. That's 0.8 points per foot for a MFH of 1000'. If you set a 700' MFH you need to use 2.0 points per foot and if you set a 501' MFH it's 400 points per foot.

3) A third objective is to not encourage pilots to thermal low. This objective is subordinate to the other two in part because it conflicts with the other two and because it's pretty clear that having everyone finish at zero feet is not a good solution to not having people thermal low. Any MFH with a penalty will yield some situations where a pilot would prefer no penalty to any penalty and will try to climb up to get out of the penalty zone. The old rule, BTW, also had this feature only with fewer points at stake. It is not clear how many pilots would reject a climb to avoid a 50 or 100 point penalty but would take the same climb when the penalty is 400 points, maybe some, but experience indicates that many pilots would take a climb at 500' for to save a small number of points.

Then there are additional considerations that shape the final solution. People hate complexity so having a variable penalty based on MFH was set aside as was restricting the MFH to 1000' because some sites need MFH lower mostly to accommodate ridge tasks. One to two points per foot was viewed by many pilots as draconian small misses so a more gentle penalty was put in place for the first 200'.

After all these additional considerations you are left with basically no room for further graduation of the penalty for MFH700' - and a pretty steep gradient even for MFH=1000'.

Also worth pointing out, the old rule only addressed the first objective, not the second or third. The new rule addresses the first and second, but not the third. Adding a 500' hard deck for 5+ miles around the finish (either to the current rule or some steeply graduated variation) would address the first two plus mitigate the third quite a bit because you'd push the problem out so far that any pilot who is facing it is already in a landout situation. Not sure the pilot community is supportive of a hard deck, even a small one around the finish, but I'd be curious to know if it's viewed as worth it in order to reduce the low thermalling temptation.

9B

On Tuesday, January 21, 2014 5:17:10 PM UTC-8, wrote:

Also worth pointing out, the old rule only addressed the first objective, not the second or third. The new rule addresses the first and second, but not the third. Adding a 500' hard deck for 5+ miles around the finish (either to the current rule or some steeply graduated variation) would address the first two plus mitigate the third quite a bit because you'd push the problem out so far that any pilot who is facing it is already in a landout situation. Not sure the pilot community is supportive of a hard deck, even a small one around the finish, but I'd be curious to know if it's viewed as worth it in order to reduce the low thermalling temptation.


A correction - the 5 mi/500' hard deck would not necessarily require a steeply graduated penalty above 500'. You can allow a modest penalty gradient for the entire distance between 500' and MFH, not just the first 200'.

You probably want the hard deck out at least 5 miles so even the most optimistic pilot who reaches the top edge of the deck will already know (s)he's not making the airport.

9B

Unfortunately the rules committee has failed to reverse a very unpopular rule change. It was clear by the overwhelming negative vote at 15M nats that the pilots don't like it.

Why not make a simple rule that gives a penalty for a finish lower than the official finish height and leave the rest alone.

How about this

1 mile finish ring at 500 Agl.

You miss it you get a 25 point penalty and -0.4 points per foot.

This would give a maximum of 225 points penalty. It gives plenty of incentive to stop and find lift.

On Tuesday, January 21, 2014 7:22:55 PM UTC-8, Tim Taylor wrote:
How about this

1 mile finish ring at 500 Agl.

You miss it you get a 25 point penalty and -0.4 points per foot.

This would give a maximum of 225 points penalty. It gives plenty of incentive to stop and find lift.

Hi Tim,

Your proposal addresses the first objective of a minimum finish height/penalty, but not the second or third (see my earlier post). Maybe you are okay with that. The pilot survey (and this thread) reveals a wide range of views and preferences on the subject. There very well may be a better alternative out there, but with a bifurcated pilot population it will need to be something outside the box to bridge the gaps in what the community would like. This discussion has exposed some potential new elements and preferences that I personally think might be worthy of further development.

Andy

Op dinsdag 21 januari 2014 14:28:50 UTC+1 schreef :
On Tuesday, January 21, 2014 7:14:15 AM UTC-5, J. Nieuwenhuize wrote:

Op maandag 20 januari 2014 21:21:11 UTC+1 schreef : On Monday, January 20, 2014 3:03:41 PM UTC-5, J. Nieuwenhuize wrote: Why not use the total height? So height (AGL) plus potential height (speed²/(2*a)) That makes ballistic pull-ups useless, allows, actually favors smooth finishes. Then set the total height rather high and substract one point per feet too low. Simply put- because this becomes a pilot and scoring nightmare. Note that each glider converts kinetic energy to potential energy differently. UH Not really; in fact they do it exactly the same way. Even an unballasted club class glider looses only a few percent (due to drag during the pull-up). Since virtually all pilots fly with a TE energy system and rely exclusively on it, I highly doubt it'd be a pilots nightmare. The ideal finish with a fixed height finish line/circle (or point substraction when too low) is fairly straightforward; fly at best MC, say 100 kts and pull up agressively, just before the finish ring. Exactly the opposite of what you'd want... A hard deck within - say - 4 miles from the finish line is a simple alternative. Get below finish height and you're scored as a land-out.



You are suggesting an alternative that requires computation in the cockpit to allow for kinetic energy and then asking the scorer to do the same. The current systems use direct measurement of one attribute (height) measured with a simple existing instrument and easily verifiable by the scorer.
If you dumb it down enough, there'll be a point where it's a simple "get up and fly as far as you can". YMMV, but the hard deck is a simple alternative, to which I can't see any major drawbacks..

The glide final scenario you describe is actaully not optimum. A perfectly flown ending has the glider at a fairly low speed, roughly the average speed for the task,and does not have a big pull up.

Yes, it is the optimum. If you fly from a given point A with a given lift to a given point B, ignoring sink or lift during the final glide, flying mac-Cready, while decreasing the altitude of point B with the potential height from the given MC gives the smalles time and thus the highest speed. Then you'd fly @ MC till you're below point B and pull up vertical. With a ground-level finish this is impossible, but flying MC until you're near the ground and coasting out in ground effect then is optimum (least time taken=highest speed)

Could we please just raise the finish height to 2000 feet and get it over with? i'll just do contest style finishes when i'm not at contests.

having made my sarcastic remark, I do appreciate the efforts to make this sport safer. the problem is you cannot prevent accidents universally, this is aviation and racing combined. Instead we need to encourage pilots to make safe decisions rather than trying to protect everyone by implementing rules.

my two cents.

2000 ft is a little high ;-), but (based on the discussion within this thread) we definitely need to consider moving MFH and any hard deck up to just above a mutually agreed "safe circling altitude." This minimum acceptable safe circling altitude is the key. I think we all agree that any finish height rule is absolutely going to cause a certain subset of pilots to instinctively try and save their points just outside the distance barrier and just below the penalty altitude.

1200 feet AGL is probably the right MFH (with graduated penalties down to 1000 AGL) as a stall spin is PROBABLY recoverable from 800 - 900 feet in most gliders. This is where the gliders "caught" by this rule will be "doing their dance!"

At 18 meter nationals last summer (due to the nature of the finishes and the lack of acceptable landing options surrounding the airfield) the MFH was moved up mid contest. There was luke warm debate although the CD managed the discussion very eloquently. Ultimately, a vote was taken and the result was in favor of raising the MFH. I think it was moved from 700 to 800 AGL.. It might have been higher. I do not remember.

1200 ft, is only 400 above 18m Nationals last summer. Clearly, it offers a greater cushion should the unthinkable happen and someone spins...

Of course, the other alternative is simply to remove this rule altogether and just allow the pilots to make their own choices. It is a quite a pickle....

Personally, I am open to both options. What I don't really like is the current rule which results in gliders circling below 700 ft and in some cases below 500 just prior to arrival at the finish location.

Sean
F2

On Wednesday, January 22, 2014 9:18:32 AM UTC-5, Andrew Brayer wrote:
Could we please just raise the finish height to 2000 feet and get it over with? i'll just do contest style finishes when i'm not at contests.



having made my sarcastic remark, I do appreciate the efforts to make this sport safer. the problem is you cannot prevent accidents universally, this is aviation and racing combined. Instead we need to encourage pilots to make safe decisions rather than trying to protect everyone by implementing rules.



my two cents.