Tying Down Your Plane

At our local EAA chapter (Marathon Ch 1241) , July is the slowest month. So, the discussion over morning coffee at the buzzard's roost (where we sit and grade landings.... a whole 'nother story) has turned to tying down airplanes. That's appropriate since we're in the potentially "windy" (AKA Hurricane) season in the Keys.

As an aside, over the years we've had more damage in Marathon to airplanes IN hangars than to those tied out. Mainly because of hangar doors collapsing onto airplanes. Also, the last "event" we had was a flood, so indoor and outdoor planes suffered equally from rising salt water.

The first thing most of us do is to install our own ropes at the tiedown spots. You can't trust those little 1/2" or 3/8" hunks of stiff rope provided by the FBO. I use the biggest rope that will go through the eyebolts on the plane. I use what we call "yacht braid" because it stays supple and, as you'll see, you can make a good knot.

Ah, the topic of knots. In this discussion we'll turn to a great source of expert and easy to understand information, the Army Field Manuals. (I kid you not. FMs explain everything (see here) and explain it well!) US Army Field Manual 5-125 explains rigging techniques. Chapter 2, (CLICK HERE) gives great descriptions of and diagrams for knots. I don't care if you are a Boy Scout or a Bosun, FM 5-125 can teach you something about knots.

Most pilots learn to use a series of half hitches to secure the ropes to the airplane in an attempt to hold down the tail and wings. But, is the half hitch good enough? As the Field Manual states, "...It will hold against the pull on the standing part of the rope;however, it is not a secure hitch." (Note the nice use of a semicolon in this Army writing!) Later, the Manual makes the point that the series of half hitches needs "constant tension on the rope" to be effective. If the airplane starts rocking, rolling, and flexing in the wind, there will not be constant tension on every rope all the time.

You can push the half hitches together and create a clove hitch. This is better, but it can still come loose and it's much harder to untie if the rope is tight. That's a pain. I think the best answer is the Fisherman's Bend.

The Fisherman's Bend requires you to put the rope through the eye twice, but that's quite possible with soft braided rope. (AKA Yacht Braid)
Then, throw a half-hitch into the end of the rope to keep it neat. This works well and you can easily untie it.

You can even print off a diagram showing how to tie the Fisherman's bend at link above. This is an efficient and effective way to tie down your airplane. Give it a try!