The 5524G borrows some inspiration from these two early pilots watches, but is by no means a literal translation. This is not an hour-angle watch at all – Patek claims the goal here was not to create a re-edition or tribute, but a fully functional watch that may be used in 2015 by a modern man. Thus, we have a travel time movement with a fully adjustable GMT-hand, the same that you'll find in both the Travel-Time Aquanaut and excellent 5990 Travel Time Chronograph. Caliber CH 324 S C FUS is what Patek calls it; we call it one of the most dynamic and usable calibers in modern horology, with a Spiromax spring and Gyromax balance made of Silinvar (Patek's version of silicon), and the Patek seal, meaning it's regulated to -3/+2 seconds per day.