What aviation taught me about building AI for lawyers

During anti-submarine exercises, I used to hand-fly a P-3 Orion at 300 feet over the ocean, at night. Roughly the size of a 737, working with frigates to hunt a submarine. There was plenty to keep us occupied.

You trust your colleagues. You also trust that the charts, coordinates and other information you rely on have been properly prepared and kept current. Somewhere, someone has done a great deal of unglamorous work so you can concentrate on the mission.

I spent 15 years as a RAAF pilot. While still serving, I founded OzRunways in 2010. Suddenly, that unglamorous work was also my job.

OzRunways put maps, navigation, weather, airfield information and notices to pilots on an iPad. It grew to serve around 30,000 active customers, and Boeing acquired the company in 2024.

The screen was the bit pilots saw. Behind it were systems ingesting information from different sources, in inconsistent formats, with errors and peculiarities that needed resolving before publication. Updates had to arrive on published cycles. Coverage had to be complete. Our work as a CASA-approved data service provider under CASR Part 175 carried formal requirements for data quality and integrity.

A pilot opening the app doesn’t need to know any of that. They find the information they need and get on with the flight.

OzRunways changed where their attention went. Less time digging through books and manually calculating flight plans. More capacity for weather, terrain, traffic and decisions. The pilot’s experience became more useful.

I’m now co-founder and lead developer of dennis.law, and much of the work feels surprisingly familiar.

The idea behind Dennis was to create a thorough legal research tool where AI reasons directly from the cases, legislation and regulations, rather than secondary sources, to produce output with the rigour necessary for lawyers to rely upon it.

A lawyer asked me: “why can’t AI just know the law?”. There are many reasons why this is a complex problem. The most advanced AIs have a working memory that means they can only “see” at most 500,000 words at once, which is obviously not enough to thoroughly research and analyse the entire body of Australian law without specialised techniques.

The most advanced AI models can only read about 20 full High Court judgments before their memories are full. To produce an advice that reads hundreds of cases and can choose the best line of reasoning with dozens of supporting citations requires advanced internal tooling.

Dennis researches within a database of Australian cases, legislation and regulations, with open-internet access blocked. No law-firm blogs standing in for authority. No headnotes passed off as judicial reasoning. The work goes through multiple checking passes, moving from the source material into the draft, then tracing the draft’s propositions and citations back to their sources.

Dennis’s database includes its own network of millions of labelled connections between cases, recording appeals and how decisions treat one another. Its research tools follow those connections through the corpus of around 400,000 cases, helping uncover relevant authorities that a keyword search can miss. The AI agents Dennis uses for research will be given these details and understand the relationship between cases. They see, for example, when an appellate Court dismisses an appeal despite disagreeing with the reasoning of the primary judge. They understand that a recent appellate decision will be important even though no other courts have yet referred to it.

I now spend my time within the databases, updates, search tools and checking systems that make useful legal research possible. Prompting the AI models to research, author and check the final product are only a fraction of the work. AIs need exactly the right amount of source material to produce a world class brief - all signal, no noise - that can fit within its limited working memory.

I don’t pretend to be a lawyer. To develop Dennis I worked closely with several barristers and solicitors, each with more than 20 years’ experience, using their feedback to refine the research, legal structure and document formatting. Since launch, Dennis is now relied upon by dozens of law firms and barristers.

For the practitioner, it should feel simple. Upload your brief, choose your side and the document you need, then press Generate. Dennis produces an opinion, written submissions or client advice as a native Word document, with live paragraph numbering, footnotes and hyperlinked authorities, ready for your review and final edit.

You bring the experience to assess risk, choose the arguments and advise the client. We take responsibility for building and maintaining the research tools underneath that work.

That’s a result I recognise from aviation. Give an experienced person better information, with less work getting to it, and they have more capacity for better decisions.

Meet Dennis at LawTech: AI in Sydney on 30 October. Start a 14-day free trial. No subscriptions; pay per product after the trial. No credit card required.