Longines - Marks 90 Years of Its Invention of the Flyback Chronograph

2026-06-16

The brand’s 1936 patent revolutionized precision timekeeping in both watchmaking and aviation

Exactly ninety years ago, on 16 June 1936, Longines recieved patent protection for its pioneering flyback chronograph, the Swiss watchmaker’s invention that transformed how pilots could measure and manage successive stages of a flight. Setting new standards in professional aviation timekeeping, the mechanism with two independent pushers went on to shape generations of pilot’s watches and remains one of the defining achievements in chronograph development. The Longines flyback’s influence and legacy of innovation continue to live on today through the Longines Spirit Flyback and Longines Spirit Pilot Flyback collections.

Turn the clock back to the 1930s: a time shaped by the relentless pursuit of progress and aviation had come to embody a new sense of possibility. From its workshops in Saint-Imier, Switzerland, Longines, whose watches were already a mainstay on the wrists of pioneering aviators, created a mechanism designed to match the speed, precision, and ambition of a rapidly changing world. The flyback reflected the brand’s enduring philosophy: to create instruments where elegance and functionality exist in perfect harmony.

A patent to usher in a new era

With the first production examples leaving Saint-Imier in late 1934, Longines moved to protect its pioneering invention, the flyback chronograph function, filing a patent application on 12 June 1935. Granted the following year and published on 16 June 1936, the patent secured 15 years of protection and gave the brand a significant lead in the development of flyback chronographs, by restricting competitors’ ability to offer comparable mechanisms. Preserved in the brand’s archives, the original drawings serve as testament to a mechanism that would go on to influence professional chronograph design, allowing the watch’s second hand to be stopped, reset and restarted with a single press. This eliminated the need to perform each action separately during flight, reducing the risk of human error, while speeding up decision-making and enabling faster real-time trajectory adjustments.

In an era when aircraft were travelling further and faster than ever before, this innovation transformed aerial navigation. Longines flyback chronographs became associated with a generation of aviators, explorers, and record-breakers pushing the boundaries of long-distance flight. In 1936, the flyback found its most enduring expression in the 13ZN calibre, today a treasure for collectors and widely regarded as one of the defining chronograph movements of the twentieth century.

13ZN: the birth of an icon

With the 13ZN calibre, Longines brought the flyback into serial production and established a new benchmark for chronograph design. Produced for only a limited period, the 13ZN remains admired for its compact construction, reliability, and unmistakable visual identity. Many early examples were delivered to Italy and the United States during the interwar years, where the rapid development of aviation helped establish the flyback among a new generation of pilots and technical pioneers, including the renowned American aviator, Richard Byrd. A pioneering US pilot and one of the foremost explorers of Antarctica, Byrd relied on the Longines flyback on his third expedition to the largely uncharted continent in 1939 and 1940. Nowadays, surviving Longines chronographs powered by the 13ZN remain highly sought-after by collectors worldwide. Beyond that, they stand as reminders of a time when aviation, engineering, and watchmaking advanced in lockstep at an extraordinary pace.

The flyback chronograph today

The reputation of the flyback has never rested on nostalgia alone, as evidenced by the role it continues to play, ninety years later, in the modern identity of Longines. Today, the flyback lives on within the Longines Spirit collection, where it is expressed through a range of chronographs inspired by the brand’s pioneering heritage. Longines reaffirmed its commitment to the flyback in 2023 with the introduction of the Longines Spirit Flyback, bringing one of the brand's most important innovations into a new generation of pilot's chronographs designed for precision, comfort and everyday wear. Powered by the self-winding L791.4 calibre, its 42-mm stainless-steel case comes with a bidirectional rotating bezel with ceramic insert, a screw-in crown, sapphire crystal with multi-layer anti-reflective treatment, and water resistance to 10 bar. The 2025 Longines Spirit Pilot Flyback showcases this heritage in a more compact 39.5-mm case, featuring the exclusive hand-wound calibre L792.4.

With a 68-hour power reserve, a monocrystalline silicon balance-spring, COSC certification, and a column‑wheel flyback chronograph mechanism, these two movements represent the pinnacle of mechanical watchmaking excellence, translating a historic pilot’s instrument into a contemporary chronograph. Across these iterations, Longines has remained faithful to the original purpose of the flyback mechanism, combining its distinctive functionality with the standards of Swiss watchmaking today. In doing so, the brand carries forward an invention conceived for aviation, preserving its essential qualities of precision, reliability, and intuitive use in a modern context.

In an age dominated by digital instruments, the flyback’s appeal lies in the enduring clarity of the concept behind it: a solution engineered to perform with speed, precision, and simplicity – when every second counts. The contemporary flyback models demonstrate how purpose-driven watchmaking resonates in the present. The result is neither a reproduction nor an homage, but the continuation of an idea that remains as relevant today as it was in the 1930s.

A legacy carried forward

Ninety years after the publication of the original patent, the flyback remains one of the most enduring achievements in Longines watchmaking history. In the second half of the year, the story will continue with the unveiling of a new take on the Spirit Pilot Flyback, demonstrating how an invention originally conceived for the pioneers of aviation continues to remain relevant with contemporary audiences.

About our movements

Backed by centuries of watchmaking expertise, Longines has played a pioneering role in numerous technical advances and continues to demonstrate an unwavering commitment to innovation. The brand’s constant pursuit of excellence has led it to equip all its a utomatic timepieces with cutting - edge movements featuring a silicon balance - spring. This material is not only lightweight and corrosion - resistant, but also resistant to usual temperature variations and magnetic fields. Its unique properties improve a watch ’s precision and longevity, allowing Longines to back these models with a five - year guarantee.

About Longines

Longines has been based in Saint - Imier, Switzerland, since 1832. The watchmaking house boasts expertise forged in tradition, elegance, and high performance. With its long standing experience as official timekeeper of world sports championships and partner of international sports federations, the Swiss watch brand has forged strong and lasting links with the sporting world over the years. Renowned for the elegance of its models, Longines is a member of Swatch Group Ltd, the world’s leading manufacturer of ti mepieces. The brand with the winged hourglass as its emblem has outlets in over 130 countries.