Traceable LLM-Generated Hazard Scenarios for Operational Safety Analysis of Aviation Systems Using ASRS Reports
This paper presents an AI-assisted framework that generates traceable and plausible hazard scenarios for aviation operational safety analysis by leveraging NASA's ASRS reports, employing large language models enhanced with evolutionary abduction to produce structured hypotheses and narrative event sequences.
Original paper licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine you are trying to predict the next big storm. You can't just guess; you need to look at how wind, pressure, and temperature have danced together in the past to create chaos. This is the heart of "safety analysis" in aviation. It's not about fixing a broken engine after it smokes; it's about using a crystal ball made of data to ask, "What if a pilot gets confused, the weather turns icy, and a computer glitches all at once?" The goal is to find these dangerous combinations before they happen, so engineers can build planes that can survive them. For decades, humans have done this by brainstorming and checking old accident reports, but the number of possible "what-if" scenarios is so huge it's like trying to find a specific grain of sand on a beach. Now, scientists are asking: Can we teach a super-smart computer to do this brainstorming for us?
This paper introduces a new AI tool called HaGen (Hazard Generator) that acts like a creative writing partner for safety engineers. Instead of just listing dry facts, HaGen reads thousands of real, historical accident reports from NASA's database and learns the "grammar" of aviation disasters. When an engineer asks, "Show me a scenario where a plane gets damaged during a clear-sky landing," HaGen doesn't just spit out a random list of errors. It constructs a full story: it picks specific, realistic causes (like a specific type of weather, a particular flight phase, and a human mistake) and then writes a vivid, technical narrative describing exactly how those factors would combine to cause trouble.
The researchers tested this tool against older, more rigid mathematical methods. They found that while the AI is great at writing the story, it sometimes trips up on the logic, inventing impossible combinations of events. However, they discovered a clever fix: they created a hybrid version called HaGen+. In this version, a different, highly logical AI first builds the "skeleton" of the accident (the list of causes), and HaGen simply fills in the "flesh" (the story). This combination proved to be the most reliable, producing scenarios that were not only realistic but also consistent and free of logical errors. The paper suggests that this hybrid approach could become a powerful assistant for safety experts, helping them spot dangerous situations they might have missed, as long as a human expert always double-checks the final work.
The Story of HaGen: Teaching AI to Dream Up Disasters (Safely)
Aviation safety is a bit like playing a game of "What If?" but with stakes as high as the sky itself. To keep planes safe, engineers have to imagine every possible way a flight could go wrong. They look at old accident reports—like the ones stored in NASA's massive database called ASRS—to see patterns. Usually, a crash isn't caused by just one thing; it's a chain reaction. Maybe the weather was bad, the pilot was tired, and a sensor failed, all happening at the exact same time.
For a long time, humans have had to manually brainstorm these chains of events. It's hard work, and because there are so many variables (weather, pilot actions, plane parts, air traffic control instructions), it's easy to miss a weird but dangerous combination. This is where the paper's authors step in with a new idea: Let's use Large Language Models (LLMs)—the same kind of AI that writes poems and answers questions—to generate these "What If" scenarios for us.
The Magic Tool: HaGen
The authors built a tool called HaGen. Think of HaGen as a creative writer who has read every single aviation accident report in history. When you give it a specific goal—like, "Write a story about a plane that gets damaged during a final approach in clear weather"—HaGen does two things:
- It builds a skeleton: It picks a set of specific, categorical factors (like "Night," "Icing," "Communication Breakdown") that fit the rules of aviation.
- It writes the story: It generates a detailed narrative describing exactly how those factors would play out in real life, using the technical language pilots and controllers use.
The paper tested HaGen using three different AI models (Llama, Ministral, and Phi) and two different ways of asking the questions (Zero-Shot, where you just ask, and Few-Shot, where you give the AI a few examples first).
The Problem: AI Hallucinations
Here is the catch. While HaGen is great at writing, it sometimes gets the facts wrong. In the experiments, the AI occasionally generated scenarios that were impossible or didn't match the rules. For example, it might suggest a plane crashed in "clear skies" when the story described a blizzard, or it might invent a part of the plane that doesn't exist.
The researchers found that simply asking the AI to "be creative" (Zero-Shot) led to a lot of mistakes. However, when they gave the AI a few examples of good stories first (Few-Shot prompting), the error rate dropped significantly. In fact, switching to this "Few-Shot" method improved the accuracy of the generated structures by about 52% compared to just asking without examples.
Interestingly, they tried to "fine-tune" the AI (teaching it specifically on their dataset) to make it better, but this actually made things worse for some models, causing them to fail more often. The best results came from using the Llama model with the Few-Shot approach and no fine-tuning.
The Solution: HaGen+ (The Best of Both Worlds)
The authors realized that while the AI is good at writing stories, it's not always good at the strict logic required to build the "skeleton" of the accident. So, they created HaGen+.
Imagine HaGen+ as a team of two:
- The Architect (EVA): This is a specialized, older algorithm that is very strict and logical. It builds the perfect skeleton of the accident, ensuring all the factors make sense together. It uses a method called "evolutionary abduction," which is like a digital evolution process that tests thousands of combinations to find the most plausible ones.
- The Storyteller (HaGen): Once the Architect builds the skeleton, HaGen takes over and writes the narrative around it.
This hybrid approach solved the biggest problem. Because the Architect guarantees the skeleton is valid, the Storyteller never has to worry about making up impossible facts. The result? The "HaGen+" tool produced scenarios that were just as realistic as the best standalone structured-only methods, but with zero invalid structures. It also made the stories much more consistent, reducing the variability in how realistic they sounded by 83%.
Why This Matters
The paper doesn't claim that AI can replace human safety engineers. Instead, it suggests that AI can be a powerful "assistant" in the loop. It can quickly generate hundreds of plausible, detailed scenarios that a human might never think of, helping engineers spot hidden dangers.
The researchers tested their tool against state-of-the-art methods for generating structured accident data (specifically those based on evolutionary search and causal structure discovery) and found that their AI-generated structured scenarios were statistically indistinguishable from those created by these dedicated, non-AI methods. Furthermore, the system provides traceability by linking each generated scenario to the most similar historical ASRS reports, offering evidence that the scenario is grounded in real-world patterns rather than just being a random invention.
However, the paper is careful to note that this is a tool for exploration, not a crystal ball for prediction. The AI generates "candidate" scenarios that must be reviewed by human experts. The authors suggest that for this to be used in real-world certification (getting official approval from agencies like the FAA or EASA), the AI would need to be part of a "Human-in-the-Loop" system, where a human always has the final say.
In short, the paper shows that by combining the logical rigor of old-school algorithms with the creative storytelling power of modern AI, we can build a better safety net for the skies. It's not about replacing the pilot or the engineer; it's about giving them a super-powered assistant to help them see the invisible dangers before they ever happen.
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