For aerotow operations in the United States, 14 CFR §91.309 governs aerotow rope requirements: ![[91_309.png]] Additionally, glider manufacturers may include aerotow rope strength and length requirements in the *Limitations* section of the flight manual - particularly if the glider was certified under *JAR-22*. ![[JAR-22 launch limitations.png]] \[from *JAR-22 Amendment 6*] ![[PW-6U aerotow and winch limitations.png]] ## Tow Rope Strength 14 CFR §91.309 explicitly describes aerotow rope strength requirements: - 80-200% of the maximum certificated operating weight of the glider A stronger rope may be used, if [[Weak Links]] are used on the glider and towplane: - Glider: 80-200% of the maximum certificated operating weight of the glider - Towplane: stronger than glider weak link; up to 25% stronger, while remaining less than 200% maximum certificated operating weight of the glider **Pilots must consult the glider flight manual, as the manufacturer may impose more stringent limitations on towline strength.** Ropes are manufactured in a variety of materials, diameters, and braids, each with different qualities of strength, durability, elasticity, cost, etc. When purchasing tow rope, check the manufacturer's data for that specific rope to ensure regulatory compliance. ![[GFH rope strengths.png]] ## Tow Rope Length 14 CFR §91.309, and the FAA *Glider Flying Handbook* and *Practical Test Standards* do not stipulate a **requirement** for aerotow rope length. In lieu of the glider manufacturer's limitations on rope length, some recommendations should be observed. The de facto standard for aerotow rope length is **200 feet**. This specific length is described as the "minimum for normal towing operations", for the purposes of avoiding pilot-induced oscillations (PIOs) in the *Glider Flying Handbook*. This minimum length "minimizes the influence of the towplane's wake and reduces the likelihood of PIOs". Additionally, a minimum length of 200 feet allows the glider pilot time to react to any disturbances of the towplane - with a 200 foot rope at a tow speed of 60kts, the glider will enter the same disturbance as the towplane approximately 2 seconds later. For aerotow operations outside the United States, pilots should be aware of any applicable regulations governing rope or cable lengths. For example, the *German Gliding Operation Regulations* does stipulate rope lengths for different types of aerotow operations: ![[German SBO aerotow rope lengths TOST catalog.png]] ## References - 14 CFR Part 91 - FAA, *Glider Flying Handbook* - JAR-22 *Sailplanes and Powered Sailplanes* - Politechnika Warszawska *PW-6U Sailplane Flight Manual* - TOST, *Product Catalog* (2022) ### by Kevin Sakson