Throughout the haze of confusion that was Spring 2020, there were watch announcements aplenty. Yet many were buried by more pressing news items. The new Khaki Aviation Converter collection by Hamilton was unfortunately not given much exposure at the time of the unveiling. So, let us change that and provide this tactical Hamilton with a second chance. To its credit, Hamilton was precisely on time with its release schedule — just like the Swiss railway network. But, as with any battle, the first casualty is the plan.

Now we are on the road to recovery, we can provide some breathing space for this collection of practical tool watches with a cracking design. The “Converter” part of the name refers to the slide rule bezel that turns bi-directionally. I am a terrible mathematician, so I will not even entertain the idea of explaining how to operate the bezel. But as an overview, aligning the known measures on the bezel will assist in calculating fuel consumption, speed, or distance.

Hamilton Khaki Aviation Converter Chronograph

Chocks away!

For those with their feet on the ground, rather than head in the clouds, the slide rule bezel also has everyday usage. You can use it to calculate tips and convert units of measurement. But, of course, it is rare for wearers of the watches with slide rule bezels to use them as intended. That does not stop the look of the bezel from being a refreshing throwback to the early days of aviation, especially for the pilots that yearn for the golden age of travel. There is an obvious comparison you can make to the Navitimer. But interestingly, that is not the first association I made — my mind drifted towards the Heuer Autavia.

The bezel resembles the landing gear on an aircraft.

Specifically, the Autavia released last year that focussed attention on the Avia(tion) side of the name. The knurling on the crown of these Hamiltons has a similar central groove. This is beneficial for grip and also resembles the landing gear on an aircraft. On the circumference of the bezel, we find the same repeating motif applied to ensure a maximum grip.

The glass is sapphire over the dial but mineral over the bezel. While it may not be sapphire over the rotating bezel, a coating brings the mineral crystal’s hardness and scratch-resistance up to a level that is comparable to sapphire. These features are seen across the range, but each model has other, subtle differences. Let’s check those out.

Hamilton Khaki Aviation Converter Auto

Hamilton Khaki Aviation Converter Auto

Firstly, the three-hander version has the date at 3 o’clock and broad sword hands with needle tips. Each marker has a corresponding numeral in line and towards the central section of the dial. You may recognize this style from the Khaki Field collection. The 42mm Auto is the smallest of the range but in no way less impactful. Powering the Auto is the H-10 movement. There has been discussion in recent times of the origins of the H-10 – it certainly is not a straightforward journey.

Hamilton Khaki Caseback

The H-10 shares its base architecture with the ETA 2824 Caliber — possibly the hardest working horse in the stable at this point. From there, the movement receives a frequency modification resulting in a power reserve boost to a healthy 80-hours and becomes the C07.111. Before inserting the movement into the case, Hamilton adds its repeating H pattern to the base plate and logo to the rotor. Once final checks are done, Hamilton christens the caliber the H-10. Luckily you can see these embellishments via the sapphire display case-back on the Khaki Aviation Auto.

Hamilton Khaki Aviation Converter GMT

Hamilton Khaki Aviation Converter GMT Auto

Next up is the GMT. This one is my favorite of the bunch. That might have something to do with the sunburst blue dial and red accents, for which I am a sucker. The date window shifts to the 6 o’clock position. This improved symmetry makes the layout more pleasing to my eye. I also prefer the 24-hour scale on the outside of the indices, rather than the inner section seen in the Auto model.

Hamilton Khaki Aviation Converter Side

As much as I like the look of the Khaki Field watch, the additional 12-hour scale on the 42mm Auto crowds the dial somewhat. To me, it appears a bit number-heavy — a bit like the computer screens in The Matrix. The GMT may bunch the 24-hour scale closer to slide rule bezel, but I still find it results in a cleaner dial with precise indications. The case of the Khaki Aviation Converter GMT is slightly larger than the Auto at 44mm. This diameter size is on the upper limit for many but not so much that it overburdens the wrist.

Hamilton Khaki Aviation Converter Chronograph

Hamilton Khaki Aviation Converter Chronograph Auto

Finally, we have the Chronograph. This is where I can see the most definite affinity to classic pilot’s watches. But that’s not to say these references lack a little modern decoration. Within the 12-hour and 30-minute totalizers is a smoky-grey gradient. Having the running seconds sub-dial with a plain black finish helps differentiate the functions too. When tracking elapsed time, you keep an eye on the central red-tipped chronograph seconds and smoky dials to eliminate confusion.

Hamilton Khaki Aviation Converter Chronograph Caseback

If you assumed the powerhouse behind the 6, 9, 12 and day-date is the Valjoux 7750, then pat yourself on the back. Likewise, with the H-10 movement in the Auto, Hamilton add their finishing touches to the 7750 to create the H-21 Si. Amongst the upgrades is a bump in power reserve from 42 to 60 hours and the silicon balance spring. Not too shabby for a sub €2,000 Swiss chronograph. As with the GMT, the case swells to 44mm. You can see more on the Hamilton Khaki Aviation collection here.

Watch specifications

Khaki Aviation Converter
Auto — H76615530 | GMT — H76715140 | Chronograph — H76726530
Black, blue
Case Material
Stainless steel
Case Dimensions
Auto — 42mm | GMT — 44mm | Chronograph — 44mm
Case Back
Auto — H-10 | GMT — H-14 | Chronograph — H-21
Water Resistance
100 meters
Leather or bracelet
Time and date, GMT, Chronograph
Auto — €1,195 | GMT — €1,495 | Chronograph — €1,995