Here’s how it works: when you use the pushers to move the local-time hour hand forward or backward in one-hour increments, an isolator uncouples the time-zone mechanism from the going train, which prevents the degradation of the balance’s amplitude and allows it to continue oscillating at a regular rate. The upshot is that the watch should continues to run with the usual accuracy while you’re using the mechanism. The movement that’s equipped with this feature — along with powering a sweep seconds hand and an analog date — is Patek Philippe’s self-winding caliber 324 S C FUS manufacture movement, which is visible through the watch’s sapphire caseback and boasts a heavy central rotor in 21K gold. Caliber 324 S C FUS — most likely a descendant of the movement that debuted in last year’s Nautilus Travel Time — is made up of 294 pieces and meets all of the stringent technical and decorative standards of Patek Philippe’s own in-house quality hallmark (For more on how these stack up to other brands’ criteria, click here). These include a rate accuracy with a tolerance of -3/+2 seconds, chamfered bridges with Geneva stripes, a circular-grained gold rotor, snailed flanks, and other haute horlogerie finishes.
The dark navy blue of the dial is said to be inspired by the body paint of 1930s American fighter planes; the big, applied Arabic numerals are made of white gold and the Super-LumiNova-coated baton hands for the local hours and minutes also aid in legibility. The skeletonized GMT hand for the second time zone conveys its information subtly: it’s placed behind the main hour hand and hidden for the times when local and home times are identical. There are separate day/night indicators for each time zone (local at 9 o’clock and home at 3 o’clock), and a brand-new date subdial at 6 o’clock that displays the date in three-day increments.
The white-gold Calatrava-style case measures 42 mm in diameter and has a flat, slightly inclined bezel. Its time-zone pushers (at 8 o’clock to advance the hour, at 10 o’clock to retract it) are equipped with a patent pending safety lock that prevents unintentional adjustments. The strap of the Calatrava Pilot Travel Time is also one we’re not used to seeing on a Patek Philippe watch: made of vintage brown calfskin leather with contrast top-stitching, reminiscent of the leather belts worn by flyboys of yesteryear. Even the buckle (also in white gold) continues the theme, echoing the look of harnesses used by aviators to keep their gear deployable without restricting their movement.
The Patek Philippe Calatrava Travel Time Ref. 5524 is priced at $47,600 and is set for a September 2015 takeoff. Below you’ll find some live shots of the watch taken at Baselworld 2015.