📝 SummarXiv

Abstract

Before 2025, no open-source system existed that could learn Lyapunov stability certificates directly from noisy, real-world flight data. No tool could answer the critical question: is this controller still stabilizable-especially when its closed-loop system is a total black box. We broke that boundary. This year, we released the first-ever open-source framework that can learn Lyapunov functions from trajectory data under realistic, noise-corrupted conditions. Unlike statistical anomaly detectors, our method does not merely flag deviations-it directly determines whether the system can still be proven stable. Applied to public data from the 2024 SAS severe turbulence incident, our method revealed that, within just 60 seconds of the aircrafts descent becoming abnormal, no Lyapunov function could be constructed to certify system stability. Moreover, this is the first known data-driven stability-theoretic method ever applied to a civil airliner accident. And our approach works with zero access to the controller logic-a breakthrough for commercial aircraft where control laws are proprietary and opaque. The implementation of the proposed framework is open-sourced and available at: https://github.com/HansOersted/stability