The author and journalist, best known for his novel "Man and Boy," moved into a hotel in the airport Wednesday and will spend a week roaming the terminals in search of inspiration for his first collection of short stories.
Describing airports as "places of extreme emotion," he said he hopes "Departures: Seven Stories from Heathrow" will revive the airport fiction genre.
Parsons said after reading Arthur Hailey's novel "Airport" growing up, his stint at Heathrow feels like an "incredible opportunity" to write about people whose lives are touched there.
"Often when we travel we find ourselves in such a hurry to get to our end destination that we fail to appreciate the individual stories and moments happening before us," he said.
Five thousand copies of the book will be given away free to passengers before going on general sale in October.
Parsons is the airport's second writer-in-residence. The first, Alain de Botton, produced "A Week at the Airport: A Heathrow Diary," some of which was written from a desk in the airport's Terminal 5.