Phase 1 Rope Screening Protocol

The RampWarden Phase 1 Rope Screening Program is designed to compare candidate aircraft tie-down ropes under a controlled static loading protocol. The goal is not to certify a rope for aircraft use, but to create a consistent first-pass screening method that helps identify which rope constructions deserve further evaluation in later dynamic, gust, wet-cycle, and snubber testing.

Why the Rope Is Tested as an Assembly

Each rope sample is tested as a real tie-down assembly rather than as a bare rope section. The test configuration uses a bowline-to-bowline rope assembly connected between two fixed anchor points. This matters because an installed aircraft tie-down does not move only because the rope body stretches. Total movement also includes knot seating, fiber bedding-in, constructional settling, and other assembly effects.

For that reason, the Phase 1 workbook separates two important measurements: gauge-section elongation and ring-to-ring elongation. The gauge section is measured from marks placed on the straight loaded body of the rope, away from the bowlines. This is the best estimate of true rope-body stretch. The ring-to-ring measurement captures the total installed assembly movement between the anchor points.

Load Schedule

The official load schedule begins with a 10 lbf baseline. The rope is then loaded through fixed static steps to 500 lbf. Each intermediate step is held long enough to allow a controlled reading, while the 500 lbf peak step receives a longer hold. After the peak load, the assembly is returned to 10 lbf and then measured again after a 10-minute rest period.

Dry and Wet-After-Dry Cycles

Each rope is tested through four primary cycles: Dry Cycle 1, Dry Cycle 2, Wet Cycle 1, and Wet Cycle 2. The dry cycles are completed first without untying the bowlines between Dry Cycle 1 and Dry Cycle 2. This helps show how much movement changes after the assembly has already been loaded once.

After the dry cycles, the rope assembly is wet-conditioned by full water submersion for approximately 12 to 18 hours. The rope is then allowed to drip briefly before wet testing begins. Wet Cycle 1 is started shortly after removal from water, and the bowlines remain tied through both wet cycles. Keeping the knots tied helps preserve the assembly condition and makes the repeated-cycle comparison more meaningful.

What the Workbook Records

The Phase 1 workbook records rope construction, diameter, dry and wet weight, minimum breaking strength, estimated wet-and-knotted strength, and wet-and-knotted working load at selected safety factors. It also records qualitative handling notes such as stiffness, visible deformation, knot stability, ease of untying, wet handling, and any unusual behavior observed during loading.

For each rope, RampWarden creates the same chart set: gauge elongation percentage, ring-to-ring elongation percentage, gauge elongation in inches, estimated knot and assembly settling, and a stacked elongation mix chart at 500 lbf. Keeping the chart set identical across all ropes makes it easier to compare candidates visually and reduces interpretation bias.

How the Results Will Be Used

The preferred Phase 1 candidate is not simply the strongest rope or the rope with the least stretch. A useful aircraft tie-down rope should show controlled elongation, repeatable behavior across cycles, manageable wet performance, limited permanent set, stable knots, and practical field handling. A rope that is too stiff may transfer more load into the aircraft and anchor system. A rope that stretches too much may allow excessive aircraft movement. Phase 1 is designed to identify the best balance.

Phase 1 is therefore a screening program, not a final product decision. The strongest candidates from this work should advance to Phase 2 dynamic and snubber testing before any final RampWarden recommendation is made.