Losing the daily round of Uckers, a traditional military board-game, would consign the 28-year-old to a shift of servitude, at the beck and call of his bell-ringing comrades.
The relaxed setting of the Uckers board outside the airmen's VHR (very high readiness) tent belies both the fierce competitive edge to the game and the ever-present threat of a call to scramble to the Apaches.
Captain Simon Beattie, Harry's flight commander, explains the Uckers routine: "It's always the thing we do first in the morning, with my flight.
Harry defended his Uckers record amid rumours he was not as good at the game as he is on the PlayStation.
Similar to Ludo, Uckers is traditionally a Royal Navy game, but it is also very popular in the Army Air Corps.