Aircraft tie down

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Bede
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Aircraft tie down

Post by Bede »

Just curious, why do we tie down aircraft, especially to "movable" concrete blocks/tires? If the wind is strong enough to move a 1600# aircraft, it's going to move 1600# +200# of concrete blocks without much more effort.

Wouldn't chocks on both main wheels work better?

Personally, I tie down into anchors in the grass, 30" into the soil.

However, right now, my skiplane isn't tied down because it's frozen to the snow (and I can't find the anchors under the snow).

Any thoughts?
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PilotDAR
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Re: Aircraft tie down

Post by PilotDAR »

A story will follow....

The POH for most 100 series Cessnas from the late '50's to the mid '60's, in section IV, "Care of the Airplane" contains the following statement: "... Tie sufficiently strong ropes or chains (700 pounds tensile strength) to wing, and tail tiedown fittings...". So, I like 700 pound as a minimum "weight" for anything on the ground to which I tie my planes - 'cause Cessna said.

Back in the late '70's, I was the custodian of a very nice 172, which the owner flew irregularly. In return for caring for it, I was allowed to fly it. It lived at a private runway owned by Max Rice, just off the no longer present Kleinburg VOR. The only other aircraft parked there was a Seabee, which was distant across the grass apron. I never saw the Seabee move in the many months I took care of the 172. Both aircraft were tied to hearty ropes, which were tied well around about a dozen stacked 24" square poured concrete patio stones. The grass was grown up around these stacked stones so as to suggest they had been there forever. One morning before six, the occupant of the farmhouse there phoned me in a panic, during the windstorm last night, the planes had blown into each other! I was horror struck, as I had used the 172 last - I flew my car down the road to do whatever I could. When I arrived, sure enough, the aircraft were now occupying the same tiedown spot - the spot I'd left the 172 in! It was the Seabee which had cartwheeled across the apron several hundred feet, wingtip floats curled up, and other corner damage. The Seabee was still tied to its stacks of patio stones, which had thrashed their way along with the cartwheeling plane.

I was in shock thinking about what damage had been done to the 172 as the obstacle against which the Seabee had come to rest. As I got closer, I could see that the Seabee wing had passed over the 172 wing, without touching it. The tiedown rope from the Seabee wing to the stack of patio stones was now deflected by the 172 aileron, whose trailing edge was a little curled. With a lot of muscle and maneuvering, I was able to push the 172 out from under the Seabee, and then taxiied it to an otherwise unused tiedown spot, and retied it. I looked it over high and low, and it was undamaged, other than for the curled aileron trailing edge. I pressed that out with a couple of pieces of sawn 2x4, and then flew it over to Brampton at a later time for a second check - nothing wrong! Ahhhh! The Seabee remained as I'd left it for a while, then was gone one day, never to be seen there again.

Form that I learned, if you think you need to tie a plane down, you need to tie it down well! Not only for its own sake, but for the more expensive thing it could hit if it got away. Sacked patio stones, tires or pails full of concrete, or a few concrete blocks just won't do it for me! if I don't think there's 700 pounds+ capacity, I'll look elsewhere for a tiedown!
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Old Dog Flying
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Re: Aircraft tie down

Post by Old Dog Flying »

My little Grumman AA1A weighed 1050 Pounds. My friend had a slightly bigger Grumman.. We were tied down side by side when an 85 Kph wind hit.. My a/c stayed put with both wings and tail tied securely while the other Grumman which was also chocked with large rubber chocks. His a/c jumped the chocks and swung 90*...by the way his was an HU-16A Albatros.

No matter what you do Mother Nature is going to piss you off and the last thing you want to do is leave an aircraft untied.
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C.W.E.
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Re: Aircraft tie down

Post by C.W.E. »

Well lets look at this in a logical way.

How much weight will your airplane lift?

At what wind speed will it fly with that weight?

I always tied down every light aircraft I ever owned and always made sure the tie down was secure enough to hold the airplane with at least twice the weight it would lift.

And just as important I "" Always "" put external locks on all flight surfaces, ailerons, elevators and rudder.
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digits_
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Re: Aircraft tie down

Post by digits_ »

Bede wrote: Mon Jan 07, 2019 5:00 pm Just curious, why do we tie down aircraft, especially to "movable" concrete blocks/tires? If the wind is strong enough to move a 1600# aircraft, it's going to move 1600# +200# of concrete blocks without much more effort.

Wouldn't chocks on both main wheels work better?

Personally, I tie down into anchors in the grass, 30" into the soil.

However, right now, my skiplane isn't tied down because it's frozen to the snow (and I can't find the anchors under the snow).

Any thoughts?
I've always been thinking the same thing: small concrete blocks won't make a difference. But if you think about it, in strong winds, it is usually the gusts that will cause problems. Having 200 lbs concrete blocks on *each* tie down, gives you an additional 600 lbs that needs to be moved, which makes it a bit more significant. Another thing, is that even a 200 lb block could prevent one wing from lifting and blowing it over. You don't need 1600lb of force to lift/flip an airplane, but maybe only half. 200 lb extra on a required 800 lb makes it more significant as well.

Bottomline, it's probably not enough, but if it's all there is, it could help a bit.

Just don't tie down a navajo with 50 lbs concrete blocks. Now you are just being silly.
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aeroncasuperchief
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Re: Aircraft tie down

Post by aeroncasuperchief »

I have heard of old wives tales about tying down, one is leave a little slack so that the taughtening of the drying wet rope doesn't break your wing! :lol: I tie mine down with about 100 pounds force each side, if a wind lifts a wing(s) its positive lift not negative lift and no worries about wing damage
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fleetcanuck
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Re: Aircraft tie down

Post by fleetcanuck »

Never underestimate the power of the wind. In '75 I hopped on a Western Airlines 727 from VR to LAX to ferry a 150 back to the VR area. There was a huge blocking high off the BC coast that aligned with the (now) Salish Sea. Many small planes were flipped in the Fraser Valley, boats were destroyed and ferries were delayed. The 727 had jumped its chocks and with the aft airstairs down, had blown about 25 feet across the ramp. We spent the next three days battling headwinds to get home.
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CpnCrunch
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Re: Aircraft tie down

Post by CpnCrunch »

This is what you need:

Image

Airport management helpfully placed this massive concrete block behind the plane after the Tripacer next to it was flipped. This plane already had the tail tied down using a screw tiedown, and it didn't move in the wind (46kt direct tailwind).
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aeroncasuperchief
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Re: Aircraft tie down

Post by aeroncasuperchief »

Ok, this is my beef ! WHY for the love of bent metal are airports all around this so-called advanced country failing to provide Proper tie-downs for both long term and itinerant aircraft? I consider this negligence and POOR customer service far from welcoming anyone to their airport/ town etc.
There should be 2000 pound underground supports AND provisions to tie down every aircraft on the airport and all those who visit!
Beef over !
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C195 Driver
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Re: Aircraft tie down

Post by C195 Driver »

I agree totally. I planned to fly to CYQW in mid December however the forecast had overnight winds of 35+ knots. With no itinerant tie downs, no hangar space available and only wheel chocks I drove 6+ hours instead. Sure enough the winds hit that night. Glad I drove. I’ve been into YXE a few times and not sure if there are any intinerant tie-downs available.

Almost all airports I’ve been to in the US have tie downs available. Not sure why we can’t have them here, especially if I’m being charged a tie down or landing fee.
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rigpiggy
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Re: Aircraft tie down

Post by rigpiggy »

super chief, because it is harder to mow/snowplow around. personally I like the 1" cable linked to a big buried anchor with secondary smaller anchors every 30-40 ft
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JasonE
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Re: Aircraft tie down

Post by JasonE »

A few winters ago I flew into Peterborough after hours. I'd called ahead to ensure:

1) Where to park
2) Tie towns were not buried in snow/ice
3) Ropes were available
4) I could plug in to preheat in the morning.

All was confirmed ok. I showed up to a crap show of a circuit, 7 or so planes in the air (Seneca). Tie downs were frozen under 2 inches of ice, no ropes (brought mine anyways) and no where to plug in the next day. I spent 40 minutes in -20 weather chiseling away at the ice with a pair of vice grips (The only thing I could find). That was fun. To top if off the next day I paid the lady at the desk for overnight parking (after waiting 20 minutes for her to get off the phone talking to a friend) and they still sent another invoice for it. Never again going into that airport.

So calling ahead doesn't always help. Be prepared to fend for yourself!
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Re: Aircraft tie down

Post by C.W.E. »

super chief, because it is harder to mow/snowplow around. personally I like the 1" cable linked to a big buried anchor with secondary smaller anchors every 30-40 ft
I installed exactly that for my airplanes when I had my flying school in 1986 and it is still there as good as the day I installed it.
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rookiepilot
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Re: Aircraft tie down

Post by rookiepilot »

JasonE wrote: Wed Jan 09, 2019 7:31 pm A few winters ago I flew into Peterborough after hours. I'd called ahead to ensure:

1) Where to park
2) Tie towns were not buried in snow/ice
3) Ropes were available
4) I could plug in to preheat in the morning.

All was confirmed ok. I showed up to a crap show of a circuit, 7 or so planes in the air (Seneca). Tie downs were frozen under 2 inches of ice, no ropes (brought mine anyways) and no where to plug in the next day.

So calling ahead doesn't always help. Be prepared to fend for yourself!
Yup, yup and yup. Gotta love Canada in the winter.
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aeroncasuperchief
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Re: Aircraft tie down

Post by aeroncasuperchief »

The running cable is a good idea. At my airport the anchors are too far apart to have the needed stiffness ( Aircraft will fly 5-10 feet in the air because of the loose cable ) I do like the imbedded hook/ snap lock idea,,,,, There MUST be forward thinking airports in the world that have come up with a reallllllly good idea for year round tie-downs !
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aeroncasuperchief
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Re: Aircraft tie down

Post by aeroncasuperchief »

PS: Smaller airport service in Canada is like comparing a drunken beggar to a millionaire FBO ( sorry , the beggar is not normally paid to provide good service, it is usually a 1 way street )
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Re: Aircraft tie down

Post by valleyboy »

I can remember one of the first times in Nuuk I saw all these tie down rings embedded in the ramp. Didn't think much of it at the time until I came back once to see all the -7's tied down. Then over the years I discover 100 kt winds are not uncommon there. 7F lost the rear door off the hawker there in high winds.

Over the years I have witnessed so many small aircraft with tie downs that one just rolls their eyes at.
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Lotro
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Re: Aircraft tie down

Post by Lotro »

Consider using lift spoilers tied to the tops of the wings if able. I hear a pool noodle can work in a pinch, but I've been eyeing these for a while: http://www.alaskawingcovers.com/
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groncher
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Re: Aircraft tie down

Post by groncher »

Pool noodles work! There was a 185 in the Antarctic that used them in conjunction with buried tie downs for years and never had a problem.
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ahramin
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Re: Aircraft tie down

Post by ahramin »

What's this pool noodle business?
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