David Warren, Inventor of ‘Black Box,’ Dies at 85

David Warren, who is widely credited with creating the prototype of the flight data recorder, or “black box,” an advance in aviation that was partly inspired by the death of his father in a plane crash when he was 8, died on Monday in Australia. He was 85.

His death, at a nursing home in Brighton, a suburb of Melbourne, was announced by Australia’s Defense Department.

Mr. Warren, a government aeronautical researcher who had operated a ham radio as a boy, worked against skepticism and ridicule to create his device. But it, and later generations of it, proved to do exactly what he thought it would: simultaneously record the conversations of pilots and instrument readings.

After a crash, aviation authorities now scramble to recover the box — encased in steel and insulated against fire — so they can determine what happened minutes before. The information not only helps fix responsibility; it has also resulted in many safety improvements.

The Institute of Electrical and Electronics Engineers credits Mr. Warren with the invention, as do many other authorities in the field. Still, he insisted, he did not invent the black box — for the simple reason that he had painted it red.

Today’s black boxes — which remain red or orange, to make them easier to find in wreckage — record far more data than the first ones and help in investigations of countless catastrophes.

The story of Mr. Warren’s invention is not an entirely happy one. First, his idea was derided. If it were practical, he was repeatedly told, the Americans would have already made it. Then the Australian civilian aviation authorities said it had “no immediate significance.” The military huffed that it would yield “more expletives than explanations.” The pilots’ union called the device a sinister way to spy on them.

The invention’s salvation was a visit by a high-ranking British aviation official to Australia. He marveled at Mr. Warren’s brainchild and flew the inventor to England to show it off. The flight was the only remuneration Mr. Warren received for building the box.

How Mr. Warren’s red box came to be called a black box is not altogether clear. At the time, black box was a slang term in the Royal Air Force for a navigational instrument in an airplane. One story has it that a person who witnessed a demonstration said something like, “What a wonderful black box!”

In any event, within two years the English were putting the device into their planes. An American company produced its own version. More and more governments began mandating the boxes.

David Ronald de Mey Warren was born to missionary parents on March 3, 1925, on Groote Eylandt, an island off northeastern Australia. He was said to be the first European child born there. At age 4 he went off to boarding school.

His father died in one of Australia’s earliest air disasters, in 1934. His last gift to his son, then known as Bunny, was a ham radio set. The boy loved it and built radios to sell to his friends. When amateur radio was banned during World War II, he turned to chemistry as a hobby.

Mr. Warren graduated with honors from the University of Sydney, then earned a diploma in education from the University of Melbourne and a Ph.D. in chemistry from Imperial College London. He went to work for the Australian Defense Department doing aeronautical research. The department lent him to a panel investigating a spate of civilian air crashes.

When he volunteered to work on developing a flight-recording system, he was rebuffed. Mr. Warren remembered his boss’s saying, “If I find you talking to anyone, including me, about this matter, I will have to sack you.”

Mr. Warren persevered. His epiphany came when he saw a German-made recording device in a store window. It could record voices for up to four hours on fine wires.

It seemed so very simple, “I couldn’t get it out of my mind,” he said in an interview in The Age, a Melbourne newspaper, in 1998. He decided to buy one, even though its cost in today’s dollars was around $15,000. His wife, the former Ruth Meadows, told The Age that she was pregnant with their third child at the time and very nervous about the expenditure.

She survives him, as do four children, Peter, Graham, Meg and Jenny; eight grandchildren; one great-grandchild; and a sister, Grace.

In 1954, Mr. Warren wrote a paper titled “A Device for Assisting Investigation Into Aircraft Accidents.” Three years later, he completed building the data recorder, which he named the ARL Flight Memory Unit. The next year, 1958, having seen his device meet only rejection, he heard an unfamiliar British accent in his laboratory. It was Sir Robert Hardingham, secretary of the British Air Registration Board.

“I say, that’s a damn good idea,” he recalled the visitor’s saying. “Why don’t we put this kid on the next plane, and we’ll show it in London.”

Mr. Warren continued to work for Australia’s government, won many honors and was mentioned on lists of influential inventors. New generations of his invention include solid-state electronics, provide more than 200 measurements, dump data 128 times a second and are self-ejecting.

He told The Age that he had no regrets about not making money from his invention. If the government had offered him all the profits from the black box, Mr. Warren said, he would have rejected it flat, “Because you’ll give me the bills for all my other ideas, too!’ ”