The flyback function - precision and innovation in timekeeping

Flyback watches, such as those used by pilots, simplify timekeeping enormously. A single push of a button sets the watch to zero and starts a new measurement process. Below we explain in detail how the chronographs with the convenient stop function work, take a look at the history of their development and see how they differ from the split-seconds chronograph.

The most important facts in brief

• Flyback function: The flyback function enables the time to be stopped, reset and restarted immediately with a single push of a button and is therefore clearly one of the complications with enormous practical benefits.

• Rattrapante (split-seconds hand): The split-seconds hand or rattrapante chronograph (from the French “rattraper” meaning “to catch up”) allows split times to be measured using an additional hand. In the Triple Split version, which was originally developed by A. Lange & Söhne, such a chronograph measures split times over a period of up to 12 hours.

• Applications: Due to its ease of use and the resulting precision, the watch with flyback function has proven to be particularly useful in aviation, sports and scientific measurements.

What is a flyback chronograph?

With a conventional chronograph, the current measurement process is simply stopped by pressing the button. To reset the hand to zero and start a new measurement, the button must be pressed two more times. Flyback chronographs, whose mechanism is also known as “Retour en vol”, simplify handling immensely by using two buttons. The first button can be used to stop the hand, while the second button triggers the zero setting. The special feature: if you press the second button while a measurement is in progress, the measurement stops and you can see the hand fly smoothly back to zero across the dial. As soon as the pusher is released, a new time measurement process begins immediately.

Technical details and how it works

The most important component for the wearer of wristwatches with a flyback complication is the pusher, which, when pressed once, stops the current stop process, sets the second hand to zero and starts the new counting process. This superficially simple principle has long proven its worth, particularly in areas where precision and fast handling are important, such as cycling races or aviation.

But a look beneath the surface shows: Flyback chronographs are by no means “simple” complications. The function is made possible by a complex movement that disengages the chronograph for the brief moment of zero setting so that the hammers required for this are not damaged. The disengagement, which in conventional chronographs is permanent or lasts until the next button is pressed, is reduced in flyback watches to the one moment when it is essential.

The development of the flyback function

Originally developed for aviation in the 1930s, the flyback chronograph can be traced back to the Longines brand. It patented its in-house flyback caliber L13ZN in 1936, making watchmaking history in the process. After a period of active military use, in which the Breguet Type XX was able to shine, watches with flyback hands gradually disappeared from the scene. It was not until 1996 that major watchmaking companies once again ventured to produce modern interpretations of the well-known flyback watches, with the Blancpain reference 2185 F being one of the most convincing models.

To this day, watches with a flyback mechanism can be considered an exception, as they are still few and far between on the market. Nevertheless, watch enthusiasts looking specifically for a model with a flying second hand have a small but fine selection to choose from, including magnificent flyback chronographs such as the Big Bang Unico from Hublot or the reference 5905 from Patek Philippe.

Care and maintenance of flyback chronographs

Every complex mechanical movement should be serviced regularly to ensure a long service life. Of course, this also applies to models with a return en vol. Every few years, the watch should be presented to a specialist who can repair minor faults and damage before they result in expensive consequential damage.

Comparison: Flyback Chronograph vs. Rattrapante

Flyback, rattrapante, split-seconds - these are all terms that are frequently used in connection with chronographs and are often confused. Time to clarify: flyback chronograph and rattrapante are two different chronograph mechanisms that must be distinguished from one another. However, the terms rattrapante and split-seconds mechanism mean one and the same thing.

When a chronograph is called a rattrapante, this means that it has two second hands that can be stopped independently of each other. The second hand - the drag hand - is synchronized with the “normal” second hand, which drags it along, so to speak. A chronograph with a rattrapante is primarily intended for stopping split times and is therefore predestined for use in races. For example, it can be used to precisely and easily measure the time that elapses between the arrival of the first athlete at the finish line and the crossing of the finish line by the second participant. By pressing a pusher, the second hand moves up to the first and synchronizes with it again so that a new process can be started immediately.

A. Lange & Söhne last took the performance of the rattrapante function to the extreme in an innovative manner in 2018. To enable split times to be stopped beyond 60 seconds, the brand introduced the double split-second chronograph with two minute hands back in 2004. Recently, A. Lange & Söhne then astonished the watchmaking world with the Triple Split, a rattrapante watch with two second, two minute and two hour hands. With this masterpiece of watchmaking, measurements of up to 12 hours are possible.

Famous flyback chronographs

Finally, we would like to briefly introduce some of the most famous and popular flyback chronographs. First of all, of course, there is the Hublot Big Bang Unico Chronograph mentioned above. The watch, which is powered by the innovative HUB1280 UNICO caliber with an “open heart” and column wheel on the dial side, has a 72-hour power reserve and is available in many different variations - for example in satin-finished titanium or with a diamond setting. These models are also worthy of note:

• Patek Philipp 5935A: Mechanical world time watch with day/night display and flyback function

• Tag Heuer Monza Chronometer: Flyback chronometer in carbon case with skeletonized dial and sapphire crystal sub-dials

• Breguet Type 20 Chronographe 2057: Elegant wristwatch with small seconds, date display, rotating bezel and luminous indices

• Panerai Luminor 1950: Flyback chronograph with rounded case corners, automatic movement and small second hand

• Longines Spirit: Sporty double chronograph with flyback function and elegant gold-plated hands

Conclusion

The flyback function is undoubtedly one of the most impressive complications the watch world has to offer. The complex technology that makes these special chronographs so easy to use is a testament to the great achievements of haute horlogerie and quite rightly exerts a powerful fascination on every watch lover.