There's another thread right now with a lot of comments about "dragging" off-airport landing sites. In the interest of not hijacking that thread, here is a dedicated thread for beating this particular horse.

Honest question- when and why would you drag an off-airport strip? There's a pretty experienced school of thought that if you are going to roll wheels off-airport, you want to be going as slow as possible, not faster than necessary. Generally if I've sized up a site with a few low passes and decided I'm going in, I'd rather "find" that rock, hole or log at 40 mph, than at 70 mph. One exception I can think of is checking your ski tracks for water, or packing out a ski landing spot. Maybe if you suspect it's soft and grabby, like a beach, then it makes sense to drag it? Obviously terrain can play a factor, as in a one-way, no go-around site.

Also, I'm a fan of something Paul Claus apparently said, that if a landing site doesn't look good by the third low pass, it isn't going to look any better after the fourth, or the tenth.

-DP

Had to stop for a bio break the other day, a dry lake bed was a few minutes ahead. I couldn't tell from the air if it was dry, and we had been getting a lot of rain, so I drug it. It was dry and didn't,t feel too soft. Came around and landed, one wheel track was softer than another, and the drag almost ground looped me. It must have been a soft spot running parallel to shore and I managed to straddle it with the mains. Weird. Dragging did not clue me into the differential, but at least I knew the base was solid so I didn't over compensate thinking it was sinking in mud.

I always "drag" a beach when conducting beach landings. I come back around and look for water in the tracks...I give it a couple of minutes so if water is going to back-fill the tracks, it has enough time to fill the tracks enough for me to see from the air.

"Dragging" the beach will also tells me if the sand is too soft. You need speed for this because if the sand is soft, and you are going too slow, the deceleration caused by the soft sand may be too much and you will end up landing...when ya don't want to!

I also "drag" a strip if I think the rocks are a bit big. I get a feel right away if it's "do-able".

I also "drag" a strip if it has varying slopes or a steep slope to it. This gives me a feel of what kind of acceleration I can expect (or not) on departure.

I don't usually "drag" a strip if it meets my critical MK 1 eyeball inspection and the slope (s) are negligable. I will still do a practice approach (or 2, 3, etc) to get a "feel" for the air, the touchdown area, the departure route, and the slope of the surface.

You're point about speed is valid though...it comes down to judgment as to when to go "fast" and when to go slow.

I have definitely dragged landing sites a time or five. I would consider it a practice with merit when field length and approach clearance are not questionable, but the surface is. Two cases where I would pull this technique out of my bag of tricks are:

1. When it is difficult to tell exactly how big rocks are on a gravel bar by visual inspection on a pass, touching the mains down will equip you with much better information, with which to make a wiser land or abort decision. The mains (especially with bushwheels) can handle much larger rocks than a tailwheel can, so if it feels rough on the mains, maybe you do not want to drop your tail on that surface.

2. As was the case for Blackrock on the desert, If you commit to a landing on sand, mud, dirt, snow or any other soft surface, you might end up on your nose, back or in a groundloop if all or part of the surface is softer than expected. I have first hand experience with nosing in on a soft surface. It felt great until I got down to about 25 mph or so, and at that point I was making plans for alternate transportation from my landing site and was committed to splitting the cases on my engine Had I pushed forward on the stick while still flying, I would have felt the drag associated with the wheels penetrating the surface and gone home.

If a landing site is surrounded by tall trees or terrain and the field is short, I want to be damn certain that the surface is firm and free from roll out/takeoff obstacles. I want to approach at a low angle when dragging and have the field length to touch the surface gingerly. I would not want to roll a site and lose speed on a draggy surface and then have the need to climb steeply to clear obstructions on departure after learning that the surface is unfit for landing.

As a general philosophy for evaluating off airport landing sites: I will land a short field or demanding approach if I am confident that the surface is good, and I'll land a soft field if the approach is open and I have considerable margin with respect to field length and options after aborting.

DP, this doesn't answer your question completely, but a summary of good technique written up my MTV here:

https://www.backcountrypilot.org/knowle ... t-landings

Great article MTV. In Crzyivan 13's Impact article, this evaluation would probably have sent him to practice on airports first and later to choose a different site than up hill in tall grass.

One consideration, should up hill in tall grass become necessary: We would probably expect to not to be able to make any surface evaluation touchdowns without being committed to landing going up hill. It would be another really tough evaluation, from walking the ground, as to the possibility of getting back out down hill in tall grass. I am not familiar with the really big tires, except on the Stearman with a R-985. Also very light airplanes with very large engines such as the 450 hp Stearman without 200 gallons in the hopper. I always had to deal with the 200 gallons in the hopper.

I'm a dragger. Very little down side to dragging. If the approach and departure path allows running a tire or two down the strip then you can check off several variables by doing so. I try to have the fewest number of unknown variables working against me.

Dragging is not always slow or fast. Sometimes I only put a little weight down. Sometimes I put a lot of weight down. Just whatever it takes to check off that unknown variable that is at the top of the list for that particular LZ.

And it's damn good practice.

I land on a lot of turn rows at the edge of farmers fields, and always drag them at least once to check for ruts. A lot of the land around here is black loamy clay, and it can be tough to tell where ruts are or big chunks of soil from the air. I'll set up for a landing and then add a hair more power than necessary and roll up on the mains, keeping the wings loaded enough to feel for any chunk or rut that will toss me back in the air.

DP, the thing Claus says about making 3 passes max and then doing it or forgetting it, is something I always think about on my 10 th or 15 th pass! But several times I have seen things I didn't see in the earlier passes, or I manage to plot a line through the hazards that are seen. For me it's like lining up a tricky pool shot, except I'm at least not holding anybody else up. I think that rule or suggestion is real variable depending on the type of terrain, brush, and rocks. I don't see any down side to however many passes it takes, well there is one, the air gets pretty churned up after a while and I've hit my own wake.

Dragging is more trouble sometimes then its worth if its a one way uphill strip, I do it a lot of the skis much less often on the tires, but like making many passes, the more info the better. It also has it's own hazards, heck sometimes the dragging was a whole lot more exciting then the actual landing as the dragging involves a lot more speed. Just typing this makes me want to go out and play.......

Guess for me it's a decision maker. Many places the plane could land if I commit, but I probably shouldn't to play it safe...

Plenty of spots I have dragged and decided they were easier than I thought, other times I question why I thought the approach and landing surface was ever going to work out.

I like planning on doing a go-around on some trickier spots, because it takes the pressure off the decision points the first time around. It certainly makes for a more relaxing landing experience overall, and I think I've used some of my better judgement (discretion!) because I had a tentative look at the place first, and then thought the better of it.

When I drag a strip, I am going at landing speed...I just don't let it slow below that as the wheels are touching. So that's 50 in my PA-22. Surface can look great, but if it is pulling at the tires, it is soft, and how soft is a matter of how hard it is pulling. I get back in the air, sort through the data, and make a decision. 3 times is absolutely plenty. More than that, you are trying to talk yourself into it...bad plan. IMHO.

Troy Hamon wrote:When I drag a strip, I am going at landing speed...I just don't let it slow below that as the wheels are touching. So that's 50 in my PA-22. Surface can look great, but if it is pulling at the tires, it is soft, and how soft is a matter of how hard it is pulling. I get back in the air, sort through the data, and make a decision. 3 times is absolutely plenty. More than that, you are trying to talk yourself into it...bad plan. IMHO.

When I make more then 3 passes, sometimes many more as mentioned, I am simply gathering more info then I can get in a arbitrary number of 3 passes. I mean, really... if you need more then a single pass some would say that you shouldn't land there. I'll have to start counting next time, not really There's a fine line between "talking yourself into a landing" and being satisfied you've identified all the potential pitfalls after X amount of passes, the exact number of passes is totally irrelevant. How many? As many as it takes, I'm not counting. Some sites get no passes before landing (easy sites, with no life changing consequences if things go wrong a bit), others get a lot (major disruptions in lifestyle and economic status if things go wrong), no set rule works for me.

I don't count flying around a looking at it as a pass, I count the low approach near-landing and the dragging of tires as a pass...so we might be on the same page...I will not drag tires more than 3 times in the same place as part of evaluation. At that point I just go somewhere else.

Troy Hamon wrote:I don't count flying around a looking at it as a pass, I count the low approach near-landing and the dragging of tires as a pass...so we might be on the same page...I will not drag tires more than 3 times in the same place as part of evaluation. At that point I just go somewhere else.

I agree with that too.

For instance, the most difficult spot I landed last year, I did about seven circuits, but only three proper drags of the wheels down the surface, each time a little slower and with more weight on the wheels. I would say that is the most closely I've inspected any spot, and three drags was plenty to know how uneven it was.

The previous circuits were looking for oversize rocks, lumps or uneven ground, or whatever else. I was also assessing the wind direction and slope, as well as measuring the available distance with the old 60 kts = 30 m/s rule.

I landed a new hilltop site today, and was thinking of this thread while I made 3 or 4 passes (OK, 5). The slope precluded dragging it, and also the onewayness of the site, that's a real word, look it up. The landing went well, and as expected. BUT, after parking on the side slope (parking brake ON) and getting out, I immediately noticed that hidden in the overall brush and grass growth (which was about what I had guesstimated height wise) were numerous sagebrush stumps, think pungi stakes.

No sage brush visible above the 14" to 18" high grass, just burned off stumps, the area must have had a fire in the last year or so, and the most volatile sage "leaf" and smaller and taller branches burned right off, but the bigger stumps/branches, wrist size, didn't. I was super glad I had the 29's, and I had them at 3.5 psi. These stumps were substantial enough to do some damage, and some were 16" high. In retrospect......I could have, should have seen them I guess, but damn I looked and they didn't jump out at me, the grass did a great camo job. The Airstreaks paid for themselves again. This was a new one on me, and another good example for having the biggest and best tires you can, and I think the low pressure I run them at helped them to just mush around any stump I may hit, rather then puncture them. I won't be going back to this site.

Interesting experience Courierguy.

I can totally relate to that. I hate landing on stuff I can't see into. I am just paranoid about it.
You have your rabbit warrens, rocks, driftwood, old broken-down fences, nesting birds, jeez - anything!

This time of year when my favourite riverbeds grow thick with autumn weeds, I go so far as to stop landing on them. I just can't stand the risk!

When I approach a potential "LZ" I carry small 6 inch kids balloons with flour inside to toss out and get a idea of wind direction . I approach and overfly the area at 100ft.AGL about 10 MPH above my final approach speed -for me this is about 70 indicated -use 20 degrees of flap and approach from several different directions . Figure the slope of the grade if I'm going up as a plus. I figure about 100 ft. per 1000 ft. above sea level -and don't forget Density Altitude . Get and use a LRI for slowest approach speed -Alternate is MAF approach with slow to stall speed about 1000 agl and take note at what speed airplane gets mushy lets just to say for instance 60 add 10% and get 66 as your approach speed at that weight -altitude. Land tail low but not "stall it in-and bounce " keep the noses up and little braking . Full flaps seem to work well for landing -EZflap.com is the ticket for control. Takeoff is 20 degrees applied quickly with nose off ground at 20 or so mph and drop nose to increase over the ground speed. Get up to about 60 and climb out.

You really can't apply a general rule of thumb like "only make three passes" to aviation, and certainly not to off airport aviation. There are simply too many variables, and too much range of experience.

Here's an example: Go ski flying when there's a lot of overflow out and about.....three passes do the trick? Not for this kid to land. Now, you're going to argue that this is "Ski flying, not off airport flying". Really? What is ski flying if not off airport flying? The point is, there's a tremendous variety of "off airport" landing sites, as Courierguy noted.

Secondly, there's the experience factor of the pilot. I have no doubt that Paul Claus rarely if ever makes more than three passes at a landing site. But you're talking about someone who does this for a living, day in and day out, and has for decades. And, he's pretty much operating in the same general area.

I teach my students to make as many passes as is required to convince one that this spot is landable. That may be one, or it may be five or six. As the person gets more experience with the plane and the whole program of off airport, the number of passes will naturally decrease.

But, don't put any arbitrary number on the investigations of a landing site.

Every pass should add something to your knowledge of that site. Sometimes, particularly when you're new to the process, it gets a little overwhelming to gather more than one or two pieces of data on one pass. Again, as you get more familiar with the process and your airplane, this process is expedited, and takes less passes.

FWIW,

MTV

182 STOL driver wrote:When I approach a potential "LZ" I carry small 6 inch kids balloons with flour inside to toss out and get a idea of wind direction

Can you explain this part in more detail?

rw2 wrote:

182 STOL driver wrote:When I approach a potential "LZ" I carry small 6 inch kids balloons with flour inside to toss out and get a idea of wind direction

Can you explain this part in more detail?

Go to dollar store and get bag of kids balloons ,small funnel -stop by grocery and pick up flour . Go home and fill balloons with flour to size of soft ball approx. tie up filler tube . Put them in airplane and keep with in reach. When wanting to check wind circle area at 2-300 ft and drop out window -and watch . In snow or ice add some food coloring to be more visible .