How to tell if a grass runway is too wet to takeoff?

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gms5002

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gms5002
I'd like to go flying tomorrow but we've had a couple days of on/off rain. Any tips on how to tell if the runway is too soggy to use? I was thinking if I drive my car on it and it doesn't make ruts it's probably fine :dunno:.
 
gms5002 said:
I'd like to go flying tomorrow but we've had a couple days of on/off rain. Any tips on how to tell if the runway is too soggy to use? I was thinking if I drive my car on it and it doesn't make ruts it's probably fine :dunno:.
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Ask the person in charge of maintaining it, then drive your car on it.
 
gms5002 said:
I'd like to go flying tomorrow but we've had a couple days of on/off rain. Any tips on how to tell if the runway is too soggy to use? I was thinking if I drive my car on it and it doesn't make ruts it's probably fine :dunno:.
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In case it DOES leave ruts - don't drive crossways on the runway or too much in the center. When I was using a grass runway more regularly I'd generally walk the field. Never know when gophers, hogs, or other beasts have done something to the runway. We used to always go make sure all of the gopher holes had been knocked down first, then flew. A walk is always a good thing because looks can be deceiving from one end.

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What kind of soil, sand, clay, any standing water in spots, how long is the grass, too many variables for anyone here to answer. Walk it your self and make a determination based what you find, don't forget that long wet grass has an enormous amount of drag, and don't forget about other factors too like temps and altitude affects.
 
Reasons to not use it:
Ground is soft and you will damage the surface.
Too much drag and you are not off the ground at a point that allows you to clear the trees and still leaves you enough room to easily stop.
 
If you sink in when you walk on it, you don't need to test it further.

Note that even if the runway is firm (ours is pretty much sitting on rock so most of it doesn't ever get soft), note that wet grass can be incredibly slippery. I had some fun when I applied the brakes on our wet runway. Fortunately, I let off them immediately and we just let the friction slow us down (fortunately we've got 3000' and I need less than a third of that even with brakes).
 
The owners of our grass strip keep the main runway well seeded and rolled. My rule of thumb: if I can taxi my 2000# oldie, I can fly. The taxi way at my end of the runway is a lot softer.

The second rule is: don't damage the runway. The locals have guns.....
 
I ended up canceling because of low ceilings. I did go walk the field though and it seemed firm. It didn't "squish" while I was walking.

My main concern was damaging the field. The runway is 2500 ft long with a large field of some sort of crop only a foot or two tall off the departure end. So I don't think I'd have a problem getting airborne.
 
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brian];1904374 said:
The owners of our grass strip keep the main runway well seeded and rolled. My rule of thumb: if I can taxi my 2000# oldie, I can fly. The taxi way at my end of the runway is a lot softer.

The second rule is: don't damage the runway. The locals have guns.....
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Yup.....:yes:

Rolling out ruts... SUCKS,,,,:mad2::mad:
 
Its not the grass, its the mud. Some of them are made of gravel and sand, and while maybe its not grass, its something green that can be mowed. That one drains really well and is usually usable when wet. It all depends. Ive seen some real mud pits that you wouldnt want to be in. At the very least youre gonna get mud all over your plane, and leave some ruts in those muddy ones.
 
Remember your weight. I was flying around in my 300LB ultralight, taking off and landing on our swampy grass strip.

A 172/182 came in to say high and promptly dug in midfield. Took an ATV to tow him out. Twice. He's lucky he didn't prop strike or flip.
 
As someone else noted, hard to say due to variables. Here are a couple of benchmarks. If it takes lots of power just to taxi, it is too soft. If you are sling mud (not just muddy water), it is too soft. I'll fly my Cub lots of days I won't fly the others. Ballon tires help. Smaller tires compound the problem.


Jim R
Collierville, TN

N7155H--1946 Piper J-3 Cub
N3368K--1946 Globe GC-1B Swift
N4WJ--1994 Van's RV-4
 
On my field it's never too wet to takeoff down hill or too slippery to land uphill.
 
I really wish someone had shot a video of the rooster tail that came from Tony and me taking off out of Gaston's in the Aztec (and Tony flying it through a lake) some years back. That would be a good example.
 
Another consideration is coming back if you have a problem. Even morning dew on our short little grass strip makes it downright slippy if the grass is clipped short enough. I wouldn't count on brakes doing anything useful in the event you needed them.
 
Ted DuPuis said:
I really wish someone had shot a video of the rooster tail that came from Tony and me taking off out of Gaston's in the Aztec (and Tony flying it through a lake) some years back. That would be a good example.
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The scariest takeoff I ever had when I was flying was taking off from a very wet runway at Gaston's in 2004 in my Cardinal RG. I had my two sons with me and the drag on the runway, along with the small wheels on the RG, really made acceleration difficult. My knees were shaking violently as I saw that ridge approaching my windshield.

It was dry when I landed on Friday, but a bunch of thunderstorms on Saturday dumped a lot of rain, making the Sunday morning departure difficult. All the calculations said it should be possible, but it is not something that I would want to do again. When I got back home I took a lesson with the Cardinal guru to ensure that my soft-field takeoff technique was proper. Other than the wet runway, the only other thing that I could find was slightly underinflated tires.

Wells
 
One sure way to tell a runway is too wet is when you see a floatplane tied to the rack of your 4-wheeler that's otherwise submerged.

Beware of puddles. At speed you hydroplane across them. As you slow they grab. That's particularly inconvenient with tail draggers.
 
My wet takeoff wasn't scary, it was more funny (at least in retrospect). I was digging grass out of the gear for 6 months.
 
One positive of a wet runway is it paints brown racing stripes on the bottom of the airplane :)

At least I hope it looks good as I'm usually too lazy to wash it off...
 
brian];1905026 said:
One positive of a wet runway is it paints brown racing stripes on the bottom of the airplane :)

At least I hope it looks good as I'm usually too lazy to wash it off...
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Back when I was based on grass...I had those brown stripes on the bottom of my wings and across my horizontal stab often!

It is also why I used to regularly go thru wheel bearings. When I had my wheelpants on, I'd regularly flush the mud out. Those 1850's technology felt seals don't seal very well!
 
Carb ice can also be a factor when dealing with wet grass.


Carb ice isn't a problem here...
 
Go drive you car down it.

Or just get some ABWs and not worry about it :D
 
James331 said:
Go drive you car down it.

Or just get some ABWs and not worry about it :D
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Yea, and you might find yourself having a "conversation" about not driving a car on the runway. Heck, I've seen people get upset about driving on the taxi way...
 
brian];1905144 said:
Yea, and you might find yourself having a "conversation" about not driving a car on the runway. Heck, I've seen people get upset about driving on the taxi way...
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Between that and getting my plane rutted in, I'm fine having some dude whine at me. If he's not going to to keep on top of runway conditions himself and post them, or take financial responsibility for damages to my airframe and pax, meh
 
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Why would he take financial responsibility for damages to your plane caused by your decisions? There's no need to rut up a runway or taxiway to check conditions.
 
UngaWunga said:
Why would he take financial responsibility for damages to your plane caused by your decisions? There's no need to rut up a runway or taxiway to check conditions.
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If you're going to prevent airmen from surveying questionable runway condition, and you're not going to provide a survey of said conditions, the damage caused is on you.


If I'm going to try to takeoff from grass after heavy rain, you bet I'm going to drive the runway, kick and scream all you like
 
Maybe I have lower minimums, but if I can't walk the runway to figure out the runway conditions, then I'm not going.

The guys with the grass strips are making little if any money on the deal. Most are private and the few that are public need our support.
 
The grass strip where I'm based is privately owned, public use...an FAA approved and funded airport. Drive an automobile down the runway without prior approval and you will likely get reported to the FAA and local law enforcement.

Would you drive down the runway at a paved airport?

I have no problem looking at our runway and surrounding areas and knowing what is safe to use and what isn't.


Jim R
Collierville, TN

N7155H--1946 Piper J-3 Cub
N3368K--1946 Globe GC-1B Swift
N4WJ--1994 Van's RV-4
 
N3368K said:
The grass strip where I'm based is privately owned, public use...an FAA approved and funded airport. Drive an automobile down the runway without prior approval and you will likely get reported to the FAA and local law enforcement.

Would you drive down the runway at a paved airport?

I have no problem looking at our runway and surrounding areas and knowing what is safe to use and what isn't.


Jim R
Collierville, TN

N7155H--1946 Piper J-3 Cub
N3368K--1946 Globe GC-1B Swift
N4WJ--1994 Van's RV-4
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Yes I would and yes I have.

We get ice spots up here, we get snow coverage which can be a little deceptive, I'll drive the runway, I've also called police and had them check and drive a runway before I made my go/no go decision.

It's not a big deal and is actually a sign of a responsible and intelligent PIC.
 
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The problem is, if soft your car will leave ruts where a plane won't. Kinds frucks things up for everybody. Not exactly what I call responsible.


Jim R
Collierville, TN

N7155H--1946 Piper J-3 Cub
N3368K--1946 Globe GC-1B Swift
N4WJ--1994 Van's RV-4
 
James331 said:
Yes I would and yes I have.

We get ice spots up here, we get snow coverage which can be a little deceptive, I'll drive the runway, I've also called police and had them check and drive a runway before I made my go/no go decision.

It's not a big deal and is actually a sign of a responsible and intelligent PIC.
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I had to fly to a remote paved strip in Montana ( Dell ) a couple of years ago in the late afternoon.. FS had no runway reports on it during my briefing , so I called the Montana Aviation Dept.. REALLY nice folks.... Told them my ETA and they set up a drive by with the local sheriff...

If the runway was snowed in /drifts the police officer would put on his emergency lights while parked on the taxi way...

If it was landable, he would have his driving lights on only... I got there are dusk, was barely able to see the windsock ( which the cop had positioned his Cruiser to illuminate) to see the direction of the wind.. And sure enough, the officer was parked with his running lights on waiting for me... Landed and taxied up the guy.. Got out and shook his hand... Turns out he had a Super Cub back at his ranch and flew all the time........

I LOVE small airports and GA....:):):)
 
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