What's the purpose of tie down rings on light aircraft?
From FlightSim
Q:
What's the purpose of tie-downs on small planes? Will any wind throw a plane into the air unexpectedly? At Lincoln Park Airport, I've seen them use tie-downs...except they use lawn mowers.
airkevin
A:
An aircraft has a LOT of surface area (try washing and waxing one), and is relatively light in weight, compared to cars, for example. And the surface of the aircraft is specifically designed to react to air movement (lift, control, etc.). So a relatively light wind will have an effect. Even on an otherwise windless day, some conditions (thermals, for example) can cause enough wind to blow a light aircraft over (or at least move it around), even though the wind may only be there for a few seconds.
Granted that a 10 knot wind won't be a problem for MOST light aircraft sitting still, but 20 knots can cause problems for many, and 30 knots can cause problems for most light aircraft.
A Cessna 172, for example, may have a maximum, fully loaded weight of around 2300 pounds (it varies a bit by model, though), less than all but the lightest of cars, and when on the ramp with no people or baggage, it'll be several hundred pounds lighter, yet there is a LOT of surface area, much like sails on a sailboat. In fact, put that C-172 on floats in the water, and it acts like a sailboat, in many ways. Floatplane pilots are actually taught to sail their aircraft on the water (not exactly like sailing a boat, but...).
Larry N.
Take a 172 with a rotate speed of about 55 knots and face into into 100km/h winds and you will see the need for tie downs pretty quick. Around here (along the Rocky Mountain foothills) winds that strong are very common all winter long. Also, as a previous poster mentioned, the plane won't have anyone inside it making it even lighter. Some light planes also have control locks that keep the elevator positioned to force the nose down if it gets windy too.
loki
Here in the Carolina's piedmont (Wilgrove), we pull the yoke back as far back as possible, and turn it to the right. We then take the passenger side seat belt and wrap the seatbelt around the yoke. Thats how we do it.
PiperPilot
I must be reading this wrong or something... If you pull the yoke back, that would make the plane bounce around more in lower winds and maybe even take off if the winds get up to 45-50 knots! Am I missing something? It seems like it would be smarted to push the yoke all the way forward, although with the seat belt that seems difficult. At Panorama, we use a control wheel lock that holds the yoke in place, with the elevator pretty far down.
Sorryboutthemess
No, you are reading it correctly. The Pipers I have flown are tied down the same way. The basic idea with locking the controls is just to keep the control surfaces from moving as they could be blown about by wind in general. Some, like the 172s I flew did keep the yoke slightly forward of neutral to help keep the plane on the ground.
loki
Many aircraft don't come with control locks, so tying the wheel or stick back with the seat belt is the next best thing. Keeping the control surfaces from whipping around in the wind is the prime purpose of a control lock, not controlling the aircraft. You don't even know which way the wind is going to come from, and the controls have minimal effect (though there is some).
Obviously, on a tailwheel aircraft, you'd want the stick back if the wind is from ahead and forward if the wind is from behind. The same is true on a nosewheel aircraft -- that's the recommended procedure when taxiing, so it should also work when tied down. But (so far) there is no way to make a control lock respond to the wind.
Finally, if the tiedowns aren't strong enough to keep the aircraft in place with the controls in the wrong position, they're likely not strong enough, either, when the controls are in the right position. But you can at least keep the controls from flopping around.
Larry N.
I can remember one time when I was back in High school and a Civil Air Patrol Cadet, we were doing a Practice SAR and it was a pretty windy day. four of the larger kids (myself included)were assigned the task of hanging on to the Wing's Cessna O-1 Bird dog while it was refueled so it wouldn't flip over because of the winds (no tiedowns in the fueling area) About a year later the same plane was tied down at Burlington airport and one night a bad thunderstorm rolled across the airport and a gust hit the Bird dog so hard it snapped the tie downs and it ended up on its back on the roof of the FBO's hangar. the tower measured winds of over 60 knots that night. And since a bird Dog can fly at about 40 knots flaps up.... you can guess the results. The plane was totaled and replaced with a 172.
Brian
A couple of years ago, I saw a Piper Seneca ripped off the tiedowns and flipped over on its back by 90 MPH winds at Jeffco airport (BJC) near Denver. Tore one wingtip and one landing gear right off.
jimrandazzo
