That TLAR doesn't look right

On Monday, July 13, 2015 at 11:03:41 AM UTC-4, kirk.stant wrote:
It's always surprised me that the 360 overhead pattern hasn't been taught in glider flying, because it is probably the easiest way to setup a consistent pattern into an unfamiliar field.

This is not new, militaries have been doing it since before WW2, and it has the beauty that it works anywhere with no ground references needed.

If you think about it, it's a variation of how XC students are taught to fly a pattern for an off field landing.

Finally, I really think glider pilots (well, all pilots) should be able to setup a successful landing from just about anywhere near the airfield, from a steep straight-in to a button-hook reversal when you realize the wind just switched directions.

It's called airmanship...

Kirk
66

I think you meant, "With no altimeter reference", not "Ground reference".

I use the same basic pattern for my home field as well as "off airport". You should always practice what you'll use.
An off airport landing can be stressful enough, why add yet another thing to deal with/stress out over?

And yes, I tend to agree with the "airmanship" comment.

A rectangular flight path is a very useful, easy to use tool when landing - especially during a strange field or off field landing.

It allows inspection of the chosen landing area, obstructions, slope, animal holes, wind, etc.

A disciplined landing pattern is practiced time and time again while learning - then is used in case it is needed at a strange location.

Inspecting common off field landing GPS traces, it is very common to observe pilots demonstrating the "wandering around" method while they desperately search for elusive lift - finally committing to the actual landing with an abbreviated, undisciplined landing pattern.

At one time, we actually taught our students to perform landings without an altimeter reference. The altimeter was covered as they entered the landing pattern. We stopped doing this because of liability concerns.

The TLAR method as described in the Glider Flight Training Manual explains the downwind leg is flown "no closer than a 45 degree angle to the landing surface" it goes on to explain the importance to have enough spacing to accommodate a proper length of the all-important base leg. A 30 degree angle is suggested as being more appropriate to ensure a reasonable length base leg that can easily accommodate judgments of both flight path and dive brake applications.

The text book further explains if the downwind leg is flown correctly, the turn onto the base leg will normally occur after passing a 45 degree angle looking back to the intended touchdown point - well within the landing area.. One of the most common errors is to turn too early and be so high that full dive brakes are necessary.

Pilots need to understand it is not normal to need either full dive brakes, or no dive brakes on the final approach, and this is a way to recognize if the landing pattern was flown correctly.

We have operated Ridge Soaring Gliderport for 40 years, and during that time, we have seen (probably) thousands of gliders landing long on our 3,300 ft runway. They wanted to stop near the tiedown area where most pilot stop, but make the common errors seen at every gliderport everywhere and end up too high and too fast on the final approach.

Off field landing accidents almost always involve landing much too long.

We have had exactly two gliders land short of our runway in the 40 year period.

Without taking the time or resources to examine every glider landing accident, The statistics will show the statistics are similar to our observations..

There is more to this subject, and this format is not appropriate for such discussions.

Tom Knauff

On Monday, July 13, 2015 at 10:44:00 AM UTC-5, Charlie M. (UH & 002

I think you meant, "With no altimeter reference", not "Ground reference".

By "Ground Reference" I meant using a known feature on the ground to initiate actions in the pattern: IP at the lake, turn downwind over the farm, base over the gas station, etc. The airfield/landing zone is the only "ground reference" that should be used.

Agree, once the pattern is started, what's the point of looking at the altimeter?

Kirk

On Monday, July 13, 2015 at 1:21:43 PM UTC-4, kirk.stant wrote:
On Monday, July 13, 2015 at 10:44:00 AM UTC-5, Charlie M. (UH & 002

I think you meant, "With no altimeter reference", not "Ground reference".

By "Ground Reference" I meant using a known feature on the ground to initiate actions in the pattern: IP at the lake, turn downwind over the farm, base over the gas station, etc. The airfield/landing zone is the only "ground reference" that should be used.

Agree, once the pattern is started, what's the point of looking at the altimeter?

Kirk

Ahhhhh..... Gotcha. Correct I don't use/didn't teach using fixed ground references, the angle was all it took.
Thus if you started early in the pattern (and you used angles), you should be further away "if it looks OK".
If you started low (and you used angles), you should be closer "if it looks OK".

Farmer Browns field does not have the lake/tree/parking lot/etc. your home field does, so the angles work there as well.

We're in agreement. ;-)

I routinely look at traces for the patterns flown to our airport, and I fly closer than all but one or two (out of roughly 75 pilots) to the runway. Measuring traces, I fly roughly 1000' offset from the runway (800' out to a max of 1200'). Entering the pattern (TLAR) and using standard trigonometry, I may be no closer than a 45 look down to be at 1000'out. I do not like to be closer than that, and I flew USAF closed patterns in a previous life. Abeam touch down point, I look to be not lower than, and hopefully right near 30 degree look down/dip...less than 30 degrees I feel low and move it in and turn in sooner. I tend to do curvilinear patterns all the way around from this range and it is smooth and easily corrected at half speed brakes.

Measuring on Google Earth, to make the same turn from 600' seems like it would require me to fly way past my normal turn in point (45 back) or really play for a full speed brake, higher bank turn--needing a much higher level of flying perfection to make the landing spot than one should safely plan for. Simple math, 2D flight: 30 degree banked turn at 55 knots = 932 foot turn diameter. Same 55 knots, 45 degree bank = 538 foot turn diameter--not much margin for error at 600' offset (Seen anyone doing that for 180 degrees of turn and maintaining full boards to get down?? Didn't think so). I routinely fly the 30 degree bank around so I guess the math is close.

I agree with others based on the traces I've seen. If someone is claiming they use 45 degree dip/lookdown abeam touchdown point, on downwind, they aren't judging the angles correctly. I see most high performance sailplanes at least 2000 to 2500 feet away on average-much further than my little Pilatus likes to be. Which is fine, if they are consistently landing correctly as stated, that is TLAR to them no matter what they choose to name that angle. Having spent years rolling into 10, 20, 30, 45 and 60 degree dive bomb patterns, I can agree with others: they are thinking they are steeper than they really are (until they get more practice most new guys are always shallow). Same reason most pilots do not really get to 45 and 60 degrees of bank in thermals when they say they do....

Oh, and Kirk, I still do come up initial, pitch out and land in my glider like we did in fighters. The radio call confuses half the club: "Inbound, 1 mile north for initial, left break, stop south."

Squeaky

On Sunday, July 12, 2015 at 2:40:56 AM UTC+12, wrote:
In the latest edition of Soaring magazine there is an article about TLAR. For those not familiar with TLAR, it is a landing approach teaching method that is based on angles as opposed to elevations and distances.
Using angles automatically compensates for variations in altitude. On downwind , if you are high, you fly further away from the runway, if you ar low you fly a shorter pattern. The TLAR method is superior and safer than trying to teach fixed distances and specific altitudes for turns.
However, I found a problem with something said in the article, but being the author a very recognized figure in the world of soaring, I was hesitant to write about it. I am refering to the dip angle between the glider and the runway on the downwind leg.
The article states "The pattern shpuld be flown so on the downwind leg, opposite the touchdown point, the pilot is about 600 feet above the ground looking down at the touchdown point at a 45 degree angle". That angle looks too high for me, and I think it could be dangerous.
I've always thought that angle should be more around 25 degrees, which would produce close to a 1-on-2 slope, as opposed to the 1-on-1 slope of 45 degrees.
The 25 degree angle will put you at around 1300 feet from the runway, or close to a quarter mile away when you are at 600 ft agl.
Getting too close to the runway prevents the pilot from having a good base leg where you can better judge your position to enter the very important base-to-final turn. In the worse case scenario, being too close will force you to use very steep banks or going for a button hook turn. New pilots and many old pilots may try to force the turn with rudder, and we all know how bad that can end.
Is 600 ft too close? I'd say it is. I'll use a typical example. In calm conditions, many gliders fly a pattern at 50 knots. In theory, the radius of a 45 degree bank turn flown at that speed is 220 ft. But that doesn't take into consideration that you start the turn from zero bank, bank to 45 degrees, stay in the bank and unbank back to zero, so at the end you have a spiral turn, followed by a circular turn, followed by another spiral. If we assume it takes 2 seconds to bank to 45 degrees, the net effect is that your turn has an equivalent radius of 310 feet. When I repeat the calculations with a 30 degree bank, the equivalent radius of the turn is 440 feet.
I am trying to spare you from the equations, but if you don't believe me, look at your flight traces in google earth, or just using google earth, measure the distance from the location of your downwind leg to the runway. On your home airport, you should have a good idea of more or less where that is. I assure you that nobody is flying at 600 ft, it would scare you. Also, take a look at the angle to the runway when you are flying. Definitely not 45 degrees. Even on your chair as you read this look down to your left or right at 45 degrees and imagine the runway is at the floor.A little steep?

I reviewed a number of my videos of flights.

I'm pretty much always passing the touchdown point at 550 - 600 ft. In some cases I'm 400m - 500m to the side. That seems to invariably be in rough turbulent conditions, and I'm then making a full brake continuous turn until on finals, and then reducing brake as required.

Most of the time when I'm flying I'm more like 600m to the side.

When directing new students I seem to usually take them about 800m to the side. This gives more time on base leg, and possible to line up with the runway with a less aggressive turn.

All flights in a DG1000.

With first time students (trial flights) I also often open full brakes just after turning final for enough time that they can observe for themselves that we're not going to make the field, then go to closed brakes to show we can still fly well past the far end of the field, and then resume a standard half brake approach. Many people express doubts that you can land an unpowered aircraft precisely, or think that you're likely to get into an unrecoverable situation. It really isn't a problem if you're paying any kind of attention at all, and this demonstration quickly clears that misconception up.

Well I finally figured out how to measure on google maps and yesterday I
made a close observation of my ground track on downwind. The results
surprised me: At 800' AGL abeam the numbers, I was about 2,000 ft
displaced from the runway. This is a bit wider than I usually fly but
the angle worked out to about 22 degrees or about half what I expected.
I'll try again next time a bit closer, but I think a 45 degree look down
will make for a very steep banked 180 degree turn to final and will
probably require about a 45 degree look back at the touchdown point.
This is fun!

On 7/16/2015 10:09 PM, Bruce Hoult wrote:
On Sunday, July 12, 2015 at 2:40:56 AM UTC+12, wrote:
In the latest edition of Soaring magazine there is an article about TLAR. For those not familiar with TLAR, it is a landing approach teaching method that is based on angles as opposed to elevations and distances.
Using angles automatically compensates for variations in altitude. On downwind , if you are high, you fly further away from the runway, if you ar low you fly a shorter pattern. The TLAR method is superior and safer than trying to teach fixed distances and specific altitudes for turns.
However, I found a problem with something said in the article, but being the author a very recognized figure in the world of soaring, I was hesitant to write about it. I am refering to the dip angle between the glider and the runway on the downwind leg.
The article states "The pattern shpuld be flown so on the downwind leg, opposite the touchdown point, the pilot is about 600 feet above the ground looking down at the touchdown point at a 45 degree angle". That angle looks too high for me, and I think it could be dangerous.
I've always thought that angle should be more around 25 degrees, which would produce close to a 1-on-2 slope, as opposed to the 1-on-1 slope of 45 degrees.
The 25 degree angle will put you at around 1300 feet from the runway, or close to a quarter mile away when you are at 600 ft agl.
Getting too close to the runway prevents the pilot from having a good base leg where you can better judge your position to enter the very important base-to-final turn. In the worse case scenario, being too close will force you to use very steep banks or going for a button hook turn. New pilots and many old pilots may try to force the turn with rudder, and we all know how bad that can end.
Is 600 ft too close? I'd say it is. I'll use a typical example. In calm conditions, many gliders fly a pattern at 50 knots. In theory, the radius of a 45 degree bank turn flown at that speed is 220 ft. But that doesn't take into consideration that you start the turn from zero bank, bank to 45 degrees, stay in the bank and unbank back to zero, so at the end you have a spiral turn, followed by a circular turn, followed by another spiral. If we assume it takes 2 seconds to bank to 45 degrees, the net effect is that your turn has an equivalent radius of 310 feet. When I repeat the calculations with a 30 degree bank, the equivalent radius of the turn is 440 feet.
I am trying to spare you from the equations, but if you don't believe me, look at your flight traces in google earth, or just using google earth, measure the distance from the location of your downwind leg to the runway. On your home airport, you should have a good idea of more or less where that is. I assure you that nobody is flying at 600 ft, it would scare you. Also, take a look at the angle to the runway when you are flying. Definitely not 45 degrees. Even on your chair as you read this look down to your left or right at 45 degrees and imagine the runway is at the floor.A little steep?
I reviewed a number of my videos of flights.

I'm pretty much always passing the touchdown point at 550 - 600 ft. In some cases I'm 400m - 500m to the side. That seems to invariably be in rough turbulent conditions, and I'm then making a full brake continuous turn until on finals, and then reducing brake as required.

Most of the time when I'm flying I'm more like 600m to the side.

When directing new students I seem to usually take them about 800m to the side. This gives more time on base leg, and possible to line up with the runway with a less aggressive turn.

All flights in a DG1000.

With first time students (trial flights) I also often open full brakes just after turning final for enough time that they can observe for themselves that we're not going to make the field, then go to closed brakes to show we can still fly well past the far end of the field, and then resume a standard half brake approach. Many people express doubts that you can land an unpowered aircraft precisely, or think that you're likely to get into an unrecoverable situation. It really isn't a problem if you're paying any kind of attention at all, and this demonstration quickly clears that misconception up.

--
Dan Marotta

It may be too high, but it's hardly dangerous. Since you can basically turn the glider around virtually on a dime (think rope break), Your distance from the runway is not critical. And you can easily lose 600 feet, or even a 1000 feet on final by just opening the dive brakes and diving at the end of the runway (don't try this in a power aircraft however).

I thought we were discussing traffic patterns, not the capabilities of pilots and machines.
As I've mentioned before, it is possible to land from many combinations of heights and distances to the runway. In this thread we are talking about a normal pattern with enough spacing from downwind to the runway, in order to arrive to a final stabilized approach with the right amount of height, speed, distance to the runway, etc.
We are trying to prevent excessive slips and manouvering in the pattern.

When landing accidents are looked at, the most common landing accident is landing too long. As I stated before, in 40 years at Ridge Soaring Gliderport, we have had two gliders land short of the runway. Probably thousands have landed well beyond where they intended - but not off the far end.

A well placed, proper length base leg is a very important judgment tool - especially when landing at a strange field. Speed control is also important as is dive brake technique.

Airspeed should be proper for the conditions and constant. The dive brakes are a good indicator how a pilot has performed the landing pattern. Full dive brakes should not be needed. Of course, a no-dive brake landing is also not using good judgment - but this is relatively rare.

A precision- flown landing pattern is based upon the need for a reasonable length base leg at a reasonable height flown at a reasonable airspeed, with a reasonable dive brake setting.

Tom Knauff