The airworthiness of your paraglider should be checked as following :
Inspection frequency is specified in each glider's corresponding manual.
Line lengths are crucial since they control the shape of the wing.
The lines « check length » is defined as the distance from the lower surface of the canopy to the inside edge of the maillons connecting them to the risers. It must be measured with 5 kg line tension.
The lines check lengths should match the lines chart table of the corresponding glider within +/-10 mm tolerance. These chart tables are specified in each glider manual. An offset of +/-50mm of the chart table is acceptable.
As part of the overall line length, the risers should be measured. The measures of each riser's branch under 5kg load should match within +/-5 mm tolerance the lengths specified in the manual.
The line breaking strength should be measured by slowly increasing the tension of a single dismounted line until it breaks.
The minimum acceptable value is defined as following :
The same calculation applies for mid and upper levels. Minimum value for upper lines is 30 kg.
The tear strength is measured with a calibrated Bettsometer. The measure should be made at the middle of a panel, near the centre of the upper surface. At 600g load, the tear should not exceed 5mm, or break a ripstop thread.
Porosity is to be measured with calibrated Porosimeter. It should be measured at least in 3 different places on the upper surface, at 20-30 cm from the leading edge, in the centre of a panel.
Minimum acceptable value is 10 seconds. Below, the glider must be flight tested for approval.
The different components of the wing should be visually checked : panels, ribs, structural diagonals and straps, plastic rods sleeves, tabs, lines, splices, risers, seams…
Any damaged part should be repaired or replaced accordingly to the manufacturer specifications and reported in the maintenance logbook.