In the article “Fabric Strength – Aircraft Fabric Covering” sourced from Aircraft Systems Tech, the paramount importance of fabric strength in aircraft coverings is underscored. Deterioration of fabric strength stands as the primary reason necessitating aircraft re-covering. Vigilance in assessing fabric strength is mandated at 100-hour and annual inspections, with re-covering being required if the minimum fabric breaking strength threshold is not met.

Fabric strength holds pivotal significance in determining the airworthiness of an aircraft. An aircraft is deemed airworthy as long as its fabric’s breaking strength remains above 70 percent of the strength required for new fabric. For instance, an aircraft originally certified with Grade-A cotton fabric having a new breaking strength of 80 pounds loses airworthiness when its fabric strength dips to 56 pounds (70 percent of 80 pounds). If re-covering utilizes polyester fabric with a higher new breaking strength, the fabric must exceed 56 pounds to maintain airworthiness.

Certification of an aircraft’s fabric is tailored to factors like wing loading and never exceed speed (VNE). Higher wing loading and VNE necessitate stronger fabric. Aircraft with a wing loading of 9 pounds per square foot and above, or a VNE of 160 miles per hour (mph) or higher, require fabric surpassing or matching the strength of Grade A cotton. For such cases, the new fabric breaking strength must be a minimum of 80 pounds, with the threshold for fabric becoming unairworthy set at 56 pounds.

Conversely, aircraft with wing loading of 9 pounds per square foot or lower, or a VNE of 160 mph or less, mandate fabric equivalent to or exceeding the strength of intermediate-grade cotton. Here, the new fabric breaking strength must be no less than 65 pounds, and the threshold for fabric becoming unairworthy is 46 pounds. Click here to learn more about Acme Mills products and services.

Photo and article with all rights reserved, courtesy of  aircraftsystemstech.com