Structural testing of the ICON A5’s airframe is one of the final steps toward FAA approval and the culmination of years of design, engineering, and testing. Following months of preparation, these tests successfully confirmed that the A5’s airframe can sustain G-force loads well beyond those encountered within the normal flight envelope.
Research, design, and validation of new aircraft structures requires a variety of tests, and one of the last milestones on our way to FAA approval is airframe static-load testing. During static testing, the measured strength of the structure is compared to simulations and design specifications to validate a safe design. Ultimate static strength tests play a critical role in ensuring a structure like the A5 wing can withstand extreme loads caused by nature, such as wind shear or other large transient forces. Although these tests are an essential part of the testing phase, it is rare that a structure ever encounters stresses of this magnitude in the real world.
The tests require strict adherence to the standards established by ASTM International, using detailed data acquisition and analysis models to evaluate how the A5’s carbon fiber structure responds to simulated flight loads. Based on those standards, weight was applied to the wings and horizontal tail of ESN-2 (Engineering Serial Number 2) while it was held in upright and inverted positions. The exercise simulated up to 4 Gs (limit load, the maximum the aircraft will experience during flight), and 6 Gs (ultimate load, which is 150% of limit load). The ultimate-load test involved applying enough weight to deflect the wingtips more than 18 inches.
ICON’s tests also confirmed that the A5’s flaps, aileron, and control linkages are able to operate freely with a full range of motion, ensuring there is no binding or jamming so the pilot can maintain full and safe control of the aircraft under high G loads.
The data produced by the testing successfully validated the A5’s structural integrity and will be used as reference materials in the FAA audit that confirms the A5’s airworthiness and clears it for serial production.