Just to add additional info to what everyone is saying here (and I used to be a lineboy
), the objective of tying down an aircraft is 1) make sure the plane stays on the ground during a gust of wind 2) make sure the plane can't be moved by the wind and 3) make sure the rope/chain slack is secured in such a way that it can't get blown into the aircraft itself on a gusty day (#3 is the one I call line personnel on all the time when I take a rented 172 cross-country...).
If there is a lot of slack rope/chain left over after tying the aircraft down, tie the rope/chain off using a single knot spaced every 18 inches or so (half a meter for you metric dudes
). Most chain tiedown setups have an extra hook in the chain for tying off the slack or adjusting a high-wing tiedown for a low-winged aircarft, but I've encountered ones that don't.
Also, if you make the rope so tight that it is pulling the aircraft, back off-the aircraft owner won't be too happy when they come back out to the plane.
Remember, treat every plane like it's your baby. You will be rewarded with complements by aircraft owners, and word spreads fast about poor line service (check out airnav.com and the FBO comments at your favorite airport!).