This existential question led me into the realms of aviation forums to see if I should even write this article. Pilots do use other tools to tell the time besides their airplane’s instruments, but it turns out that anything goes – so don’t be surprised if you see an egg timer in a hobby pilot’s cockpit.
“I love watches and I’ve searched for years for a watch that was cool looking and actually useful when flying and I haven’t found one yet.”An answer by user GdD in the Aviation Stack Exchange to the question of “Do pilots really wear pilot’s watches?”
Sorry to destroy the romanticism, but amongst all the high tech instruments, there is little use for a mechanical watch.
Still most forum users said that pilots still enjoy wearing a mechanical watch. Probably for the same reasons as us: we like tiny mechanics. We love the precision. We like the design. We enjoy the haptics of a well-made watch. Most commercial or recreational pilots also haven’t found a watch yet that meets their expectations of a true pilot’s watch. This means that a watch would match the criteria of on-board aviation instruments in terms of durability and usability. Looks like that is about to change.
No one asked, but here’s the DIN 8330
A sheet of DIN A4 paper will be exactly 29.7 cm tall, no matter where you buy it. If you need cash, you can rely that anywhere in the world your bank card will fit into the ATM slot. Standards ensure that manufacturers produce goods that are compatible, safe and have a high quality.
Standards sound bland, but they make our life easier.
A4, 297 × 210 mm (DIN EN ISO 216)
There are also some curiosities in the Land of Standards. Standard ISO 3103 deals with how to prepare the perfect cup of tea. Six pages of definitions all the way down to the shape of the teapot and how to pour the milk. Thank God we settled that.
Laco was one of those surprise encounters at this year’s Time To Watches in Geneva. I heard about the brand here and there, but wasn’t familiar with their models. I also never had a Laco on the wrist, since Swiss retailers selling German watches is still not the norm (get it?).
I was surprised to see that there is a lot of history in Laco watches and that the people behind the brand really care about how their products can be used. You’ll see in the following story why this might be the watch that a pilot would want on their wrist if conditions demand it.
The birth of a new standard
It all began with the “Technical Standard for Pilot Watches” (TESTAF), developed in 2012 by Frankfurt-based watch manufacturer Sinn in collaboration with the Department of Aerospace Engineering at Aachen University of Applied Sciences. This TESTAF document was a great first step, but wasn’t strict enough. The DIN 8330 goes a step further and adds stricter test criteria for magnetic resistance, readability, vibration loads, and resistance to liquids typically found in aviation, like kerosene. In addition, requirements for compatibility with night vision devices are defined for the first time. The new standard was introduced in 2016.
Source
laco.de
The goal of the standard is to bring back the original idea of a pilot’s watch, which certifies that it’s insensitive to the physical powers that occur during flight and that it could fully replace the time-measuring instruments inside the cockpit. Kind of like divers, that mostly use electronic dive computers, but still wear a backup dive watch, should the other one fail.
“I think something like the DIN standard for the pilot’s watch is a typical German thing. Standardizing things and making it clear what you can expect from the product, what requirements the product meets and what you get for your money. And also to know exactly in which bandwidth and in which environment conditions the product works.[…] It’s good to have this really measurable and not just described in soft words or nice phrases, but really with hard facts.”
Uwe Rücker, CEO of Laco, in this interview.
Source
laco.de
Watches that comply with DIN 8330 are designed to completely replace the cockpit timekeeping instruments if they fail or malfunction. That requires the watch to go through 16 individual tests, which ensures that they are functional, resilient, and safe.
16 steps how to make a great Pilot’s watch
Let’s walk through the different criteria and tests that the Hamburg GMT fulfills. That way it doesn’t only look nice, but also makes it a professional tool.
Functionality
Readability
Fast, clear and exact readability of the time, during the day and at night, as well as under difficult conditions such as strong vibrations.
Usability
The watch must be usable with gloves. The big “onion” crown and bezel have grip and aren’t too finicky.
Accuracy and power reserve
The rate deviation must be better than ±30 seconds per day – this is not very strict. The Hamburg GMT with its Sellita SW300 movement in the Top grade provides ±4 seconds. A level of precision I’d expect for a watch in this price class.
The power reserve must be at least 36 hours, which is not long for today’s watches. If you consider that a long commercial flight without refueling between Hong Kong and London is about 23 hours, that is plenty. And it’s an automatic watch, which means that as long as you wear it, it will keep going. The Hamburg GMT has 50 hours of power reserve.
Resistance to external stresses
Source
laco.de
Environmental pressure
A negative pressure test and a pressure change test simulate the stress on the watch caused by changes in pressure during an aircraft’s constant ascent and descent during daily flight operations. The test involves two hours in a pressure chamber with at least 2,000 repetitions.
Vibration resistance
The watch is mounted to a vibrating plate that moves between 2, 10, 30 and 60-times a second.
Source
laco.de
Source
laco.de
G-force testing
It must resist up to 6 g acceleration. To put this into perspective, imagine accelerating from 0–300 km/h (186 mph) in just 1.4 seconds. At 4 g humans tend to black out. The watch is tested in three positions.
Impact and shock resistance
The Hamburg GMT is hit with a small hammer going at 4.5 meters per second.
Source
laco.de
Source
laco.de
Resistance to liquids
The watch components are “marinated” for 24 hours in different fluids, like kerosene, diesel, lubrication oils and other chemicals. After that time the components are inspected and have to still be intact and not corroded. The Hamburg GMT is also water resistant up to 20 bar (200 meters).
Protection against magnetic fields
The Hamburg GMT can resist a magnetic field of up to 1,000 gauss – just like the Rolex Milgauss, just at a fraction of the cost and not marketed as heavily.
Source
laco.de
Security and compatibility
When conditions are tough, you don’t want to lose your watch. That’s why the lugs of the Hamburg GMT have a hole and the strap is secured with a screw. That makes the whole construction tough, but also means that a spontaneous strap change takes a few extra minutes.
Europe’s air traffic management organisation Eurocontrol reported an average flight delay of 15 minutes for June 2025 – that should give you enough time for that strap change and still be able to board in style.
Screwed lugs for additional strap security.
Anti-glare materials
The sapphire has an anti-reflective coating on both sides of the glass. It has a dark blue hue, when holding it against the light.
Wrist circumference: 17.5 cm (6.89″)
The dial stays readable even in direct sunlight.
Magnetic signature
Every object that contains metal (especially steel) can slightly affect the surrounding magnetic field. That influence it creates on a magnetic field is called a magnetic signature. If you for example bring a steel screwdriver close to a compass, the compass needle moves because the screwdriver’s magnetic signature disturbs the Earth’s magnetic field.
If a pilot’s watch has a strong magnetic signature, it could cause the needle of the magnetic compass in an airplane to deflect. Here even just a few degrees of error could be dangerous.
The Hamburg GMT therefore has such a small “magnetic fingerprint”, that the compass in the cockpit is not thrown off.
The Hamburg’s case appears to be made from titanium, but it’s actually made from stainless steel. To be more precise, it’s 904L steel, which contains over 20% nickel, which is about twice as much compared to 316L steel. The higher amount of nickel stabilizes the austenitic crystal structure, which makes the steel basically non-magnetic.
Funnily enough adding nickel tends to make steel magnetic – at least if you keep it below 8%. But above that threshold the reverse happens: the steel becomes amagnetic, which is what the Hamburg GMT wants to achieve amongst magnetic fields that occur in a cockpit.
The bidirectional bezel has 60 steps and contains a matte ceramic insert, which is essentially scratch free.
Compatibility with cockpit lighting and night vision devices
In an airplane you have special lighting so that you can read the instruments at night without blinding you. The lume of a watch certified after DIN 8330 can’t be so bright that it blinds you or clashes with instrument lighting.
Military pilots and some civil aviation pilots also use night vision goggles (NVGs), which are sensitive to certain wavelengths of light. The glow of a DIN 8330 watch has to stay NVG-friendly so night vision gear doesn’t get overwhelmed and the glowing elements start to visually “bloom”. This limits the design choices, but makes sure the dial is perfectly readable under all conditions.
“Blooming” of lights that are overwhelming night vision goggles.
Movement
Inside the Hamburg GMT is Sellita’s automatic SW300 movement in the Top grade, which gives it an accuracy of ±4 seconds. This is almost the highest grade, after that you’ve only got the Chronometer quality level. Again trying to win the game against magnetism, the movement is protected by an internal soft-iron cage, which typically shields against magnetism of up to 1,000 gauss. Click here to see the full spec sheet for this movement.
Considering that there are a lot of magnetic fields in an airplane, there is a real life application for those anti-magnetic properties. Every electric current produces a magnetic field, so if you’re reading this on your smartphone, you’re holding a mobile magnetic field. Some of them emit around 50 Gauss, which is enough for the balance spring of some watches to become magnetized, which results in the watch running too fast. So having a watch that is immune to this just makes it a better partner for everyday life.
How it wears
You know that I’m not a huge fan of judging a watch by its spec sheet. The same goes for the Laco. You might read the diameter of 43.5 mm and think that this watch is fairly large. The opposite is the case! Lug-to-lug the watch is only 49.8 mm. And below you can see that the watch wears great also on a smaller wrist measuring 14.5 cm (5.71″) in circumference.
Wrist circumference: 14.5 cm (5.71″)
The Laco Hamburg GMT on a smaller wrist.
Wrist circumference: 14.5 cm (5.71″)
Wrist circumference: 17.5 cm (6.89″)
What has the watch got to do with Hamburg?
If you go through Laco’s inventory, you’ll see that many Pilot’s watches are named after German cities. Amongst others there is a Münster, Leipzig or a Memmingen. This Laco is the Hamburg. The story spans back to a war-plagued continent, where the navigators of pilots were relying on mechanical watches for navigating the airplane. Those watches were called Beobachtungsuhren (observation watches), up to 55 mm in diameter and built by many brands, such as IWC, Lange & Söhne, Stowa, Wempe and also Laco.
Together with the watch you get a testing certificate signed by Laco’s CEO Uwe Rücker.
The German Naval Observatory in Hamburg, the Deutsche Seewarte, played a central role in testing watches, including observation watches. It was founded in 1875 and was an institution for testing marine chronometers, pocket watches, and pendulum clocks until 1945. Observation watches were also part of this. It’s not the deepest historical connection, but I think it fits, since the Hamburg is a new and modern watch compared to Laco’s other pilot watches, which are mostly recreations of historical aviation classics from the middle of the 20th century.
Similar to the aesthetic of a rugged aluminium suitcase, you get a nice metal box for your Hamburg.
Why the Hamburg earned its wings
Over the time I had with the Hamburg GMT DIN 8330, I became convinced that this is the watch not just borrowing the look and “inspiration” of aviation history, but here the watch actually meets the environmental conditions of modern-day flight. Withstanding pressure changes, 6G forces, magnetic fields and exposure to chemicals is not just marketing lingo, but you can take it for granted. It’s certified after DIN 8330, black on white.
I like that such a tool watch doesn’t have to be an unwearable hockey puck on the wrist, but wears really great because of its short lug-to-lug distance. This makes the Hamburg GMT wear surprisingly well, even on smaller wrists as you see in my photos.
There are lots of pilot’s watches out there, but if there is one that really excels in this category, it’s the Hamburg GMT.
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