Two standards, great confusion: Many watch manufacturers, such as Rolex, use the designation GMT for their models with two time zones. Other manufactures, such as Rado or Sinn, call the same complication UTC. We explain the similarities and differences between the two designations and why the differentiation is crucial in many applications.

Greenwich Mean Time: Historical reference value

If you are looking for a difference between UTC and GMT, you will notice it when comparing the time: Both clocks permanently show the same time. GMT” stands for “Greenwich Mean Time” and refers to the time zone running through the prime meridian in London. We get it by subtracting one hour from our Central European Time (CET). Nowadays, Greenwich Mean Time has the status of an ordinary time zone and does not enjoy any special status compared to the 37 other time zones currently used on the globe. This was not always the case: before the introduction of UTC on January 1, 1972, Greenwich Mean Time served as an international reference time and was used as a standard in science, aviation and various other fields. The existence of such a reference time is indispensable: Uniform time information is essential not only in meteorology, but also for Internet-based applications, in space and even in Antarctica.

Lack of precision due to solar time calculation

A look at these application areas already suggests that maximum precision is of enormous importance when using a global standard time. However, this absolute accuracy cannot be achieved with the help of Greenwich Mean Time because it is based by definition on the mean solar time in Greenwich and thus depends on the rotation of the earth. The latter slows down over the years, which distorts the accuracy of the time. Much more precise is atomic time. After the world’s first atomic clock is constructed in 1949 and enormous increases in accuracy are achieved in the course of the 1950s, the official definition of a second based on atomic time follows in 1967. This lays the foundations for establishing an international time standard with perfect precision. Especially in the context of the Internet, science and space travel, even the smallest deviations can be disastrous.

UTC: Universal Time Coordinated with Atomic Precision

Since 1972, the Universal Time Coordinated (UTC) is the time standard which fulfills exactly this precision. Calculated by the International Bureau of Weights and Measures (BIPM) near Paris, its seconds cycle runs evenly with the SI seconds of International Atomic Time. Thus, between UTC and GMT, we can note the difference that Greenwich Mean Time is a time zone, while Coordinated Universal Time denotes a standard from which all time zones are derived. Coordinated Universal Time itself is not a time zone! By definition, Greenwich Mean Time corresponds to the “starting point” of Coordinated Universal Time, which is why both quantities look identical on two clocks placed side by side.

This does not mean that both quantities are exactly the same. Since London time is calculated using the Earth’s rotation and coordinated world time is calculated using the atomic clock, there is a small difference in the range of milliseconds. However, the difference is always less than 0.9 seconds because leap seconds are inserted into coordinated world time to compensate for the slowing rotation of the earth. This is done on an irregular basis; the last leap second was added on December 31, 2016. With the addition of this second, the last minute of the month lasts 61 seconds instead of 60, ensuring that our clocks do not permanently tick too fast.

By the way: The fact that there is a difference between UTC and GMT is underlined with the unique notation of the coordinated world time. In the IT sector, for example, you may have already encountered the three letters of Universal Time Coordinated. A complete specification provides not only the time but also the date and year. Example: You want to specify April 10, 2023, 12:15 p.m. and 30 seconds:

Basic format: 20230410T121530

Extended format: 2023-04-10T12:15:30

UTC and GMT: difference in the watch industry

In ordinary everyday use, there is no difference between UTC and Greenwich Mean Time that would be relevant for watch enthusiasts. Regardless of whether manufacturers talk about GMT watches or use the designation of Coordinated Universal Time, in both cases we’re talking about a time indicator that represents a second time zone in addition to its ordinary time. For many enthusiasts a nice gimmick, but for travelers and especially pilots a useful tool in everyday life. For example, those who switch between zones on a daily basis can adjust the main time and permanently set the second hour hand to home time. In addition, rotatable 24-hour rings allow lightning-fast programming of additional time zones.

Although “Universal Time Coordinated” would be a more contemporary and modern term for this complication, most manufactures still refer to GMT watches. The term is simply more familiar to most people, as evidenced first and foremost by the highly sought-after Rolex GMT-Master II. In all price ranges, from Tissot and Hamilton to the Breguet Classique collection, manufacturers use the old reference time designation. There is often a tendency for more traditional models to be called GMT watches, while the focus on technical innovation, progress and modernity is reinforced with the abbreviation of Coordinated Universal Time.

Second time zone: top watch models with UTC designation

Predestined for such a focus is the Frankfurt-based premium brand Sinn, which sets itself apart from the bulk of watch manufacturers with unique selling points such as Ar-Dehumidifying Technology and HYDRO Technology. Those with a penchant for two time zones should set their sights on the Sinn 105 St Sa UTC (Ref. 105.020): Winner of the Red Dot Product Design Award 2021, it highlights its second time zone with a bright orange hand. The additional hour display runs on a 24-hour basis, as the inscription on the bezel reveals. As a captive rotating bezel with a black hard coating, it scores with first-class robustness, which continues with the bead-blasted stainless steel case (41 millimeters). The legibility of the Sinn 105 St Sa UTC is unbeatable, and the water resistance of 200 meters is on a good Diver level.

Rado is also one of the most innovative manufacturers: above all, its ceramic expertise gives the traditional Swiss brand a high reputation and sets its model range apart from the masses. The best proof is provided by the Rado HyperChrome Classic Automatic UTC (Ref. R32050203): Limited to 999 pieces worldwide, it integrates its additional hour hand in a particularly elegant way and, at a powerful 44 millimeters in diameter, delivers a proud overall package at a good price-performance ratio.

In addition to the 80-hour power reserve of the automatic movement, sapphire crystal, 100-meter water resistance and, most importantly, the use of in-house plasma high-tech ceramics make the Rado HyperChrome Classic Automatic UTC a strong overall performer.

Der Beitrag UTC and GMT difference? erschien zuerst auf Uhrinstinkt Magazine.

Since its debut, the Breitling AVI (Ref. 765 1953) Re-Edition has been celebrated by brand enthusiasts: Conceived as a tribute to the legendary “Co-Pilot” of 1953, the re-edition inspires with its amazing closeness to the historic original and combines great tradition with modern mechanics. From 2022, additional emotions will be created by five brand-new Classic AVI watches, which will keep the pilot’s watch company with its XXL diameter and fighter plane DNA.

Comeback of an icon

Outside the world of watches, there are only a handful of timepieces with universal recognition. The Rolex Datejust or the Omega Seamaster featured in the James Bond movies are such examples. And certainly the Breitling Navitimer, often dubbed the most famous pilot’s watch of all time, is one of them. In the unprecedented fame of the classic watch with its distinctive slide rule, introduced in 1952, another icon of post-war history is almost forgotten: The Breitling AVI Ref. 765, which was launched a year after the Navitimer and quickly earned the nickname “co-pilot.” Like the second man in the cockpit, the model is an important complement to the Navitimer at the time.

Not everyone likes the complex appearance of the slide rule and is all the more pleased with the simple, robust design. In appearance, the Breitling AVI is a tribute to the Swiss manufacturer’s functional on-board watches from the 1930s and 40s, not necessarily known for their beauty. Few contemporaries would have expected that these watches would receive a tribute almost 70 years later. In 2020, the moment of glory arrives: with the Breitling AVI Ref. 765 1953 Re-Edition (Ref. AB0920131B1X1), the Co-Pilot returns to the limelight and, with a limited edition of 1,953 pieces, finds its way onto the wrists of aviation enthusiasts and brand fans.

Only the technology is modern – plus two small details

The exclusivity begins on the case back, where the lettering “ONE OF 1953” reveals: this pilot’s watch is not ready-made. But one thing at a time. The stainless steel case of the Re-Edition measures 41.1 millimeters, which not coincidentally corresponds to the exact diameter of the historical prototype – the complete new edition is modeled on the historical prototype down to the smallest detail.

The journey through time continues with the all-black dial, whose Superluminova coating is applied by hand and is identical in color to the luminous color of the 1950s model. The shape of the dial has also been precisely adapted to the first Breitling AVI.

Like the original, the totalizers appear in the same color as the rest of the dial. Even the syringe shape of the central hands is unchanged from the original. Inside the pilot’s watch, modernity reigns supreme. The watches from 2020 are fueled by Breitling’s manufacture caliber B09, which is largely identical to the B01, but replaces its automatic movement with a traditional hand-wound one. The 21st century benefits include COSC certification and 70 hours of power reserve.

Even more strictly limited: Breitling AVI in noble metals

Those who want to celebrate the ticking tradition with an additional prestigious case material can replace the stainless steel case with an 18-karat rose gold version (Ref. RB0920131B1X1). Limited to 253 pieces, it swaps the black leather strap of the regular Classic AVI watches for a vintage-style brown variant. The pinnacle of luxury is a platinum version limited to 153 pieces (Ref. LB0920131C1X1) with a blue dial and gold leather strap.

Both noble metal editions have an exclusive engraving with their respective number of pieces on the case back, are water-resistant to 30 meters and are powered by the same hand-wound movement as the stainless steel model.

Relatives with style: The Aviator 8 editions

All three new versions are grouped under the umbrella of the new Classic AVI collection, whose members have a close historical connection to the early history of the Swiss company. An established family member is the Aviator 8 Chronograph 43, whose name comes from the legendary Huit (French “huit” for “eight”) Aviation Department. Founded in 1938 by Willy Breitling, the special department was responsible for the production of the company’s highest-quality pilot’s watches in its time and established the myth surrounding Breitling’s on-board watches.

Fueled by non-manufacture movements, the Aviator 8 Chronograph 43 scores higher on affordability and exists in several special edition models – the most popular being the military green Curtiss Warhawk (Ref. A133161A1L1X1) and the black, red and white Mosquito (Ref. AB01194A1B1X1). Those who prefer simple elegance over elaborate chronographs will also find what they are looking for in the Classic AVI watches: The Automatic Day & Date 41 (Ref. A45330101B1X1) compresses the date, time and day of the week in a timelessly distinguished design.

Next Generation: New Super Aviator in Goliath format

From spring 2022, the Classic AVI watches are complemented by five newcomers that measure a whopping 46 instead of 41 millimeters in diameter and are therefore entitled to bear the name “Super Aviator”. Each model in the new collection pays homage to one of the most important fighter planes of the 1940s, with the legendary North American P-51 Mustang receiving two editions.

Firstly, a stainless steel version with a black dial (Ref. AB04453A1B1X1), secondly, an 18-karat red gold version with an anthracite front (Ref. RB04451A1B1X1). It is the only model made of noble metal.

Back in the steel world, we encounter the elegant Tribute to Vought F4U Corsair (Ref. AB04451A1C1X1) honoring the U.S. fighter plane with gull wings, as well as the military-looking Curtiss Warhawk (Ref. AB04452A1L1X1) in green design.

The most striking is the Super AVI B04 Chronograph GMT 46 Mosquito (Ref. YB04451A1B1X1) with black ceramic bezel, white contrasting totalizers and red accents. This pays tribute to the legendary De Havilland DH.98 “Wooden Wonder” which, despite being made of wood, was one of the fastest aircrafts of the 1940s.

All five Super Aviator editions are powered by Breitling’s in-house manufacture B04 movement, which adopts the technology of the better-known B01 with its ratchet wheel control and vertical clutch – 70-hour power reserve and COSC certificate included. An added bonus: 100 meters of water resistance, which sets the Super AVI noticeably apart from the 30 meters of the AVI 1953.

Der Beitrag Breitling AVI erschien zuerst auf Uhrinstinkt Magazine.