Spring is here, and the sod is soft

[PilotDAR]

It's day two rolling my grass runway, to smooth out winter's frost heaves and bumps. As I ride up and down the runway on the tractor, I was thinking to ask the eager aviators out there to ask before landing on someone's grass runway before the middle of May. Failure to do so could mean at least putting ruts into it, and becoming memorable in a not good way. At worst, you dig the wheels right in, and damage the plane. This time of year, it's best just to stay to firm surfaces, and surfaces you know well.

Should you ask, satisfy yourself that the information you're getting is to your liking. Last year at this time, I planned to venture to another Ontario airport, and park my plane for a few days. I phoned first, and asked about tiedowns. I was told "park on the grass". Doubtful, I asked if it was firm enough, and was told it was fine, airplanes had been using it.

When I pulled off the paved taxiway to the spot instructed, I sank my plane up to the axles. After being kindly pulled out, I commented that I had taxiied as instructed. Apparently the kind voice on the phone really had no idea about the conditions, and no planes had been anywhere near there since the thaw.

Be sure....

[iflyforpie]

I remember seeing the MAF guys with a stick to test the softness of the ground and the suitability for flying off of it. It was like the handle of a shovel or broom that tapered to a point at about a 20-30 degree angle. The taper was divided up into three sections.. top third was no-go for any aircraft type... middle third was good for light aircraft with big tires (206, Kodiak, etc) , then the bottom third was good for King Airs etc etc.

I wish I could find the drawing or a similar device... might come in handy if you want to do due diligence ground scouting your landing areas.

[Posthumane]

IFP, what you're describing is essentially a rudimentary cone penetration test. It's a pretty good way to measure the bearing capacity of soil.
http://en.wikipedia.org/wiki/Cone_penetration_test

[pelmet]

Back in the days of flying skydivers, the airport I flew from had a paved runway but nothing else was paved. It was really weird how in some areas at that airport in the spring, the ground would get so soft but it seemed to be more underneath the first few inches of soil. You could walk on the ground no problem but the ground would deflect downward almost as if it was pure water underneath.

I do remember one year, it had dried out quite a bit and in a less boggy area, our new chief pilot wanted to taxi the airplane. He knew it was soft, so he took a run at it thinking that by going fast it would help but the nosewheel sank in and the prop dug a nice pattern into the ground. Walking on the area later in the day, it was a bit soft but didn't seem too soft. I guess it is just better to wait as light aircraft wheels are quite narrow compared to many other vehicles. Of course if you have tundra tires.......