The launch of the Code 11.59 collection is a crucial moment for Audemars Piguet. There has been no product launch of this magnitude over the past 20 years for the brand. In this respect, the Code collection presentation was the perfect opportunity to introduce a long-anticipated development that was announced a few years ago: the Audemars Piguet Calibre 4400, an in-house, integrated chronograph movement – by no means a small achievement since chronographs are extremely difficult to develop.Long awaited, finally here!Until now, Audemars Piguet has manufactured a few high-end chronographs in-house in the Le Locle APRP manufacture. However, the brand relied mostly on outsourced chronograph movements – either integrated with the Piguet-based?FP1185, or modular with Dubois-Depraz modules on top of the in-house 3120 Calibre. At last, the long-awaited Audemars Piguet in-house, integrated chronograph is now here! Ad - Scroll to continue with article The Audemars Piguet Calibre 4400 chronograph is a high-end, modern chronograph that has been five years in the making. Its construction focusses on performance and efficiency, and it incorporates several interesting technical specificities. The development started just a few months after the appointment of Fran?ois-Henry Bennahmias as CEO of the brand. In 2013, Bennahmias gathered his product and production teams, literally locking them in a meeting room and stating, nobody leaves the room until we have agreed on the key options and laid the foundation for the development of a chronograph movement.The Audemars Piguet Calibre 4400 encased in the Code 11.59 Chronograph.Following this mandate, Audemars Piguet developed not one but two movements, both 14''' in diameter and part of the same family: The AP 4300, an automatic base calibre – used in its AP 4302 variant in the Code collection The AP 4400, an automatic, integrated flyback chronograph – used in its AP 4401 variant in the Code collectionNaturally, both movements have a lot in common and share several components. They utilize the same barrel, the same regulator and common parts for the keyless works or wheel train. The look and feel are familiar with that of the previous Audemars Piguet movements, in particular with the design of the bridges.The new time-and-date AP4302 Calibre – self-winding movement, 32mm x 4.80mm, 32 jewels, 257 parts, 70h power reserve, 28,800 vibrations per hour. Functions: hours, minutes, seconds and date.Chronometric precision was a key factor in the development of these two calibres. For enhanced stability, Audemars Piguet has opted for a transversal balance bridge rather than a balance cock. On each side, there is a screw to adjust the balance end shake. The oscillator operates at 28,800 vibrations per hour. The large balance wheel has an inertia of 12.5 mg/cm2?to provide optimal stability. It features 3 harms and 6 adjustment weights. The large barrel ensures a healthy 70-hour power reserve. Winding is bi-directional thanks to two reversers with ball bearings – a comparable system was already used by Audemars Piguet for the AP4101 Calibre.Audemars Piguet Calibre 4400 – The new In-House, Integrated chronograph of the Code 11.59 collection.If the crown/stem operation is traditional (Position 1 for manual winding, P2 for quick date setting set, P3 for time setting), the keyless works integrate a smart patented solution. An oscillating pinion drives the selection of the function. When the crown is pulled, a wheel (that becomes inclined!) engages with the date correction wheel or the time correction wheel. This architecture avoids any backlash when pushing the crown back in.The Calibre 4400The Chronograph Calibre 4400 is a high-end, modern construction with a focus on performance and efficiency. This large movement (32mm) is an integrated construction with a column-wheel and vertical clutch.The vertical clutch of the Audemars Piguet Calibre 4400.Coupling?– A solution found in most modern chronographs, the vertical clutch enables absolutely precise starts and stops. As its name indicates, the connection of the chronograph mechanism with the timekeeping gear train is executed vertically and by friction, similar to the systems found in automobiles. The theoretical advantages of vertical clutch chronographs are that there are no teeth to engage or disengage, a principle that may cause the jump of the chronograph seconds hand when the teeth mesh.When you stop the chronograph, you disengage the drive train from the chronograph mechanism. At the same time, brakes are applied on the hour and minute recorders while the chronograph seconds feature a friction mechanism.Start-Stop-Reset – One of the first things to catch your eye on the Calibre 4400 are the three twin hammers and hammer springs. The hammers are responsible for resetting the hands. When the brakes are lifted, the hammers fall on heart-shaped cams rotating these until the hammers come to rest on the two shoulders of the heart and immobilize it.The three hammer springs are almost identical and positioned one next to the other. Not only is the function smooth and complete but it is really cool to see these in action one next to the other, which is superbly highlighted by the architecture of the movement.Flyback chronograph –?The AP 4400 is a flyback chronograph, which means it can be returned to zero and restarted instantly with a single push of the button. This function allows rapid retiming without the need for pressing pushers three times in succession to stop, reset and start the chronograph. But this means extra complexity as the reset must be operated without breaking any part, and the hammers then need to be disengaged to restart the chronograph.In the foreground, the clutch, the column wheel and chronograph mobiles. In the background, a chronograph hammer and hammer spring.Decoration – Finishings on the Calibre 4400 include straight and circular satin brushing, Geneva stripes and perlage – on both sides of the bridges, even in the hidden areas. The bridges feature large chamfers, perfectly diamond polished. Engravings are gold-toned. The 22K gold rotor is openworked with the AP logo, which offers a superb view of the mechanism.As with all Audemars Piguet watches, the timepieces equipped with the Calibre 4400 come with a 5-year warranty. For more information, please visit www.audemarspiguet.com.Audemars Piguet Calibre 4400 – Specs Architecture:?Integrated, automatic, column-wheel and vertical clutch, flyback chronograph Dimensions: 32mm x 6.8mm Frequency: 28,800 vibrations per hour Balance wheel: variable inertia, 6 weights, 12.5 mg/cm2 Power reserve: minimum 70 hours Winding: automatic, bi-directional Coupling: vertical clutch Jewels: 40 Functions: hours, minutes, seconds, date, flyback chronograph