For years the FAA snubbed its nose at angle of attack system retrofits for certified light aircraft. A handful of owners got lucky when the shop was able to sneak field approval paperwork through the FSDO, while others ran into a regulatory roadblock when field inspectors deemed AOA retrofits too major of a modification to approve. The expensive and time-consuming chase for additional supporting data often put an end to the project. That’s changing.
Under a new policy, manufacturers must build the systems according to standards from the American Society for Testing and Materials (ASTM) and apply for FAA approval for the design via a letter certifying that the equipment meets ASTM F3011 standards. That makes it easier for shops to win installation approval and easier yet for manufacturers to market a new breed of AOA systems to an industry that’s recognized the AoA indicator as a useful tool for avoiding aerodynamic stalls.