If the original rib stitch spacing cannot be determined when re-covering an aircraft, what rib stitching should be used?

Using the rib stitching spacing chart in advisory circular 43.13-1B is the best approach when the original rib stitch spacing cannot be determined. This advisory circular serves as a vital resource for aircraft maintenance practices, providing standardized techniques and recommendations for various components, including rib stitching, which is crucial for maintaining the structural integrity of the aircraft wing or fuselage.

The chart in the advisory circular outlines effective spacing guidelines based on the type of fabric and the aircraft's design characteristics, thereby ensuring the re-covering process adheres to safe and accepted industry standards. This is particularly important for maintaining compliance with regulatory requirements and ensuring the safety and airworthiness of the aircraft.

While consulting the manufacturer's guidelines or previous coverings might seem reasonable, they do not offer the same assurance of compliance and optimal performance as the established guidelines in the advisory circular. Relying solely on averages or personal judgment may lead to inconsistencies that could compromise the effectiveness of the stitch, thereby affecting the aircraft's performance and safety.