American Aerolights Eagle

Trailing edge failure

A significant number of American Aerolights Eagles have suffered in-flight break-ups as a result of failure of the wing trailing edge. The Eagle has single left and right aluminum spars at the leading edge. The wing fabric is Dacron. The wing is composed of several panels stitched together. The aircraft, when assembled, maintains wing shape by tensioning the wing fabric. The "bowsprit", i.e., the structural tube which holds the canard (the small wing in the front of the main wing), is the attach point for the main tensioning wires. These wires exert a strong forward pull on the spars. This pull, in turn, places substantial tension on the trailing edge of the wing fabric. Over time, the Dacron fabric weakens, as do the stitched seams, especially at the aft center section which is often soaked and soiled by fuel and exhaust. If the wing fabric fails at the trailing edge, it will tear from back to front, and the wing will lose its shape and most of its lifting ability. This failure is likely to lead to catastrophic loss of control and lift. It is impossible to predict if and when this will happen; the wing may look sound, even though it is dangerously weak.

Remedy

The factory, before it closed, and most reputable sailmakers, advised re-inforcement of the trailing edge in one of two ways: (1) Attach a strip of heavy nylon webbing along the trailing edge, from wing tip to wing tip, properly stitched along its entire length. Most sailmakers wrap the webbing around the trailing edge, and stitch through the web, top and bottom, with the trailing edge sandwiched between the folded-over web. (2) Same as number 1, but with the added precaution of inserting a stainless steel cable in the fold of the web, attached to the wing tips.

IT IS UNSAFE TO FLY ANY EAGLE WHICH HAS NOT HAD THIS MODIFICATION!!!!!