The Melbourne chemist who taught aeroplanes to tell their own story
In 1953 and 1954, the world's first jet airliner, the de Havilland Comet, broke apart in mid-air more than once. Investigators had little to go on beyond the wreckage.
David Warren, a fuel chemist at the Aeronautical Research Laboratories in Melbourne, was brought in to test whether the fuel tanks had exploded. For him, unanswered questions about air crashes were personal. In 1934, when he was eight, his father died when the Miss Hobart crashed into Bass Strait. Nobody could say why it went down.
A small recorder and a big idea
At a trade fair, Warren saw the Minifon, a pocket-sized recorder that stored sound on steel wire. If one had been running in the Comet's cockpit, investigators would know what the crew saw and said in the final minutes.
In 1954 he wrote a short memo proposing a crash-protected cockpit recorder. By 1956 he and a small team had built a working prototype, the ARL Flight Memory Unit. It recorded up to four hours of cockpit voice, plus eight instrument readings sampled four times a second.
Australia said no
The RAAF said the recorder would capture "more expletives than explanations". Pilots disliked being listened to. The Department of Civil Aviation showed no interest.
The breakthrough came in 1958. Sir Robert Hardingham of the British Air Registration Board saw the device and invited Warren to demonstrate it in England. Production began in the UK.
Two years later, a Fokker Friendship crashed into the sea near Mackay in Queensland, killing everyone on board. The inquiry could not establish the cause and recommended flight recorders. Australia became the first country in the world to make cockpit voice recorders compulsory.
Bright orange, not black
Today every large passenger aircraft carries two recorders in the tail, the part most likely to survive a crash. They are painted bright orange so searchers can find them.
Warren earned almost nothing from his idea. The Defence Department decided a patent was not worth the cost. Recognition came late, including an Order of Australia in 2002 and a Qantas A380 named after him in 2008. When he died in 2010, aged 85, his family marked his coffin: "Flight Recorder Inventor. Do Not Open."
The coins
The black box is the only invention in the Royal Australian Mint's 2026 Bright Ideas collection with two coins: the $1 Black Box Flight Recorder and a coloured $1 version.