He was born in the Brighton area in 1921 the youngest child of Frederick Warren Pearl and his wife Amy Lea Duncan.

In 1915, his father, Surgeon-Major Frederick Warren Pearl had been appointed to the American Embassy in London. With his wife, three daughters, a son and two nursemaids, they had boarded the RMS Lusitania in New York. On 7 May 1915 she was torpedoed by a German submarine and went down eleven miles off Kinsale.

Pearl had been in his stateroom when he heard the explosion. His wife had seen the torpedo hit from the deck. They sent the nursemaids and children up to the deck and followed them. Due to the crowds on deck, they lost contact with their children. After three hours in the water, Pearl was picked up by a lifeboat, and was rescued by a trawler. In Cobh, he was reunited with his wife who had been rescued by a tramp steamer. Their youngest daughter aged three months, and her brother were rescued as their nursemaid managed to get them onto a lifeboat. The other daughters and their nursemaid lost their lives.

The baby, Audrey, married Hugh Lawson-Johnston and was the last survivor of the Lusitania. She died in January 2011.

His parents retained strong connections with England living, variously, in Lowndes Square and at 7 Princes Gate in London.

Duncan was educated at Eton and Matriculated in 1940. He was up at Christ Church for a year.

He was gazetted as a Flight Sergeant on 14 March 1942 and promoted on 20 November.

He was a Flying Officer [Pilot] when he died on active service on 26 March 1943.

Originally, he was buried in the Cambridge American Cemetery Plot E. Row 1. Grave 51.

Later his body was repatriated and he is commemorated on the Maidenhead Register.

Those named within the Register were all non-Commonwealth foreign nationals who died serving as members of Commonwealth Forces. Their remains were removed to their home countries and are presently commemorated solely by their database record and register entry. The register is maintained at C.W.G.C. Head Office, Maidenhead.