Light aircraft are most often secured with ropes tied only at the aircraft tiedown rings provided for securing purposes. Rope should never be tied to a lift strut, since this practice can bend a strut if the rope slips to a point where there is no slack. Manila rope shrinks when wet; about 1 inch of slack should be provided for movement. Too much slack will allow the aircraft to jerk against the ropes. Tight tiedown ropes put inverted flight stresses on the aircraft, many of which are not designed to take such loads.
A tiedown rope holds no better than the knot. Antislip knots such as the bowline or square knots are quickly tied and are easy to untie (figure 11-22). Aircraft not equipped with tiedown fittings should be secured in accordance with the manufacturer's instructions. Ropes should be tied to outer ends of struts on high wing monoplanes, and suitable rings should be provided where structural conditions permit, if the manufacturer has not already provided them.