No other complication has taken centre stage on the dial of the Big Pilot's Watch more often than the perpetual calendar. Developed during the 1980s by IWC's former head-watchmaker Kurt Klaus, the large dial not only lends itself well to the mechanism's many display, but it also makes reading of the calendar information particularly easy. The Big Pilot's Watch Perpetual Calendar features a stainless steel case, a blue dial, rhodium-plated hands and a blue calfskin strap. The perpetual calendar automatically recognizes the different month lengths and the leap years, and will not require a manual adjustment until 2100. Engineered from only about 80 individual parts, the calendar module is driven by a single nightly switching pulse from the IWC-manufactured 52615 calibre. Components of the Pellaton winding system that are subject to severe stresses are made of virtually wear-free ceramic. When fully wound, the two barrels store a power reserve of seven days. The elaborately decorated manufacture movement is visible through the sapphire glass back.