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Runway condition concerns


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Hi everyone.  On a cross country last year I stopped for fuel at PNC because of the price.   The A/FD lists the runway condition as "Fair".   During the rollout I was afraid of a prop strike in our C.  The runway surface was so uneven, but with some periodicity, and our airplane started "bucking" .    I'll never land there again.

This raises the question: Since our Mooney's don't have what I would consider excellent shock absorption, should we avoid everything but "Good" runways?   Any other trick to find good landing surfaces other than avoiding "Fair" runways?

Thanks,

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It's always a good idea to keep your Mooney, light on it's gear. Good soft field technique is always a good plan. But I wouldn't limit where I can go in the Mooney, within reason, of course.

I've been in and out of gravel strips in Northern Canada, in and out of BurningMan several times, and to numerous other grass and less than "good" runways. I've never had a problem with my 252 or the M20C. The 252 has the extra low gear doors as well. 

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48 minutes ago, Bravoman said:

Mooneys have terrible shock absorption. The oleo system is way better. I guess there is a design reason it wasn’t used in the Mooneys.

Mooney landing gear pucks evolved from the M18,  which initially used International Harvester rubber tractor motor mounts for the Mooney gear. 

Mooney engineers experimented many times over the years whether to change to the oleo system, as was used on the M22 Mustang.   Obviously, that never happened !

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Soft field landing technique does not address what I'm talking about.    I know how to land an airplane slow and easy and I usually do <knock on wood>.

Let me restate my question:   From about 1994-2017 I didn't fly much in the U.S.  I got busy with job and family and didn't fly at all from 2006-2017.   In my experience before 1994, mostly in the '80's, runways were generally in pretty good shape.  Fast forward to now, in this age of deferred maintenance and infrastructure budget cuts, the quality of the random runways seems to be worse.   I never used to see grass and weeds growing up between cracks in the runway surface or potholes on taxiways.   Now these things are not hard to find at all.  The runway at PNC was, I think, unsafe to land a Mooney on no matter what the speed or landing technique.

How to avoid crappy runways?    Only go with ones that the A/FD lists as "good"?   I have satisfied myself in one case for sure that "fair" isn't good enough.  Any thoughts?  

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I’m not sure how to answer your question. Are you looking for better info than the A/FD?

If the runway is less than good, call the airport and ask them.

The worst runway I ever landed on was 27R at KELP back in the 90s. It had cracks in the asphalt that would swallow your wheels. 

The Mooney landing gear it tougher than you think and unless there is something sticking up about 6 inches, the prop isn’t going to hit it with the mains on the ground..

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I have to agree with comments above. I fly my 252 on a few dirt runways every winter and have been for many years and I've visited many runways that pilots all complain about and the mooney does just fine with the proper technique. I personally have never felt the need to avoid crappy runways with the exception of uneven grass runways cause we really don't have the suspension to be bouncing in and out of grass holes (sorry there are better words to describe it) that causes significant rattling of your airframe as you rollout. That is something I want to avoid. But little 1/4 to 1/2 potholes aren't a big deal IMO, nor is some grass. 

But make sure your pucks are still in decent shape  so that your plane isn't handling like a tank as you taxi around at slow speed. Perhaps that is part of the issue?

To me, some of worst to use runways are just uneven surfaces usually from heat damage that causes waves in the surface - not that uncommon with asphalt in the SW US, and pretty typical with a dirt runways. But keeping the yoke back so that nose wheel gets off the runway as soon as possible will greatly smooth out your ride as well.

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2 hours ago, 0TreeLemur said:

My experience was best described as "resonant coupling" between the runway and the airplane.  Scary.

That’s the point that everyone is missing. Happens in seaplanes if the periodicity of the waves is just right for a certain speed. The pitching up and down builds in amplitude. It is an underdamped oscillation. The same thing can happen on a runway. It’s not just roughness or bumpiness; it requires a surface with a periodic spacing between peaks and troughs. It is unlikely to persist over the entire length of the runway, so if encountered on landing, the safest  thing is to go around and try again touching down in a different spot.

There used to be an freeway structure in Oakland CA that had supports at regular intervals and a definite sag between them. It used to be great fun for a young engineer to find the exact speed to drive that would result in the maximum periodic vertical motion of the car’s suspension. Then the Lomita Prieta earthquake happened in 1989 and this section collapsed.

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I learned a couple of summers ago, that in the great white north, gravel runways are much better than paved runways. With all the freezing and thawing, the gravel runways just get graded and are good to go. The paved runways just get worse and worse until after a few years, they get rebuilt.

Pro Tip: Avoid CYTH and go to CYGX instead. And when at CYYQ you want the short gravel runway rather than the very long concrete runway.

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11 minutes ago, PT20J said:

That’s the point that everyone is missing. Happens in seaplanes if the periodicity of the waves is just right for a certain speed. The pitching up and down builds in amplitude. It is an underdamped oscillation. The same thing can happen on a runway. It’s not just roughness or bumpiness; it requires a surface with a periodic spacing between peaks and troughs. It is unlikely to persist over the entire length of the runway, so if encountered on landing, the safest  thing is to go around and try again touching down in a different spot.

There used to be an freeway structure in Oakland CA that had supports at regular intervals and a definite sag between them. It used to be great fun for a young engineer to find the exact speed to drive that would result in the maximum periodic vertical motion of the car’s suspension. Then the Lomita Prieta earthquake happened in 1989 and this section collapsed.

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Happened to me while taxiing on the smoothest ramp I can recall seeing. Crossed a taxi entrance to the runway, turning away, and thought for a minute the Mooney was going to leap into the air. I braked very gently, and after not much more than a dozen oscillations, it calmed down. But for three or four hops there, I was worried!

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15 hours ago, PT20J said:

That’s the point that everyone is missing. Happens in seaplanes if the periodicity of the waves is just right for a certain speed. The pitching up and down builds in amplitude. It is an underdamped oscillation. The same thing can happen on a runway. It’s not just roughness or bumpiness; it requires a surface with a periodic spacing between peaks and troughs. It is unlikely to persist over the entire length of the runway, so if encountered on landing, the safest  thing is to go around and try again touching down in a different spot.

There used to be an freeway structure in Oakland CA that had supports at regular intervals and a definite sag between them. It used to be great fun for a young engineer to find the exact speed to drive that would result in the maximum periodic vertical motion of the car’s suspension. Then the Lomita Prieta earthquake happened in 1989 and this section collapsed.

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That is the reason for landing a little long at KCHA. The ripples in the first 1000' get you bouncing upon landing and start an oscillation on take off. Landing just a little long on 20 still allows the turnoff into the FBO to be easily made.

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