Williamson Mk IV.A

Pilot’s Watches – Part Two – 1914 to 1918


As you may have read in our Dive Watch Blog, any war is a major catalyst and motivator for the development of equipment that may prove useful to armed forces.  Scientists and engineers are freed of ‘normal’ responsibilities and governments make funds available to them.

Interestingly, during the war, the pilot’s wristwatch was abandoned as a concept in favour of the old style panel mounted pocket watches.  The Air Forces preferred tried and tested technology at such a critical time, but there was still much that the watch industry could learn.

The Royal Air Force (RAF) didn’t exist during WW1.  In 1911 the British Army’s Royal Engineers Air Battalion & the Royal Naval Flying School combined to become the Royal Flying Corps (RFC).  Then in 1914, the Royal Navy re-established its own specialist airborne division, the Royal Naval Air Service (RNAS). These were the two forces that carried out the ‘Balloon Busting’ missions and took part in the famous and deadly dogfights.

For most of the pilots, the Mark IV.A and Mark V pocket watches were standard issue which they would carry onto the ‘plane and then fit into a bracket on the instrument panel – they became known as ‘Cockpit watches’.

In order that they could be wound during flight to maintain optimum accuracy, these pocket watches had a long winding stem and a large ‘onion’ crown

The ‘Mark’ watches were made by various manufacturers who didn’t sign the movements – Mark IV.As were often made by Smith and Mark V by Zenith and Omega among others.  As well as being issued to the Air Forces, they were sold through selected London retailers such as London’s Williamson’s and Birch & Gaydon.

Williamson Mk IV.A
Omega Mark V
Williamson Mk IV.A

It was during this critical time that manufacturers really focused on defining the vital features of a pilot’s watch and these are the characteristics that remain in place today:

The Dial – This must be both large enough and clear enough for a pilot to tell the time in varying conditions and sometimes under extreme pressure.

The Lume – In order to be read at a glance in the dark, the lume on the large legible dial needs to be very clear and bright.

The Crown – When these watches were designed it was normal for the pilot to fly wearing large leather gloves that made it impossible to work a standard crown.  Consequently, they were designed with oversized ‘onion’ crowns on long stems that they could use without removing their gloves.

The Bezel – Some pilot’s watches have more complicated bezels (Breitling Navitimer for instance), to allow the pilot to make extra calculations while flying.

GMT Functions – Nowadays, many pilot’s watches have a dual time or GMT feature allowing the wearer to tell the time in two over even three time zones simultaneously.

The Clarity of the IWC Top Gun Dial
The IWC Aquatimer Lume
The large crowns on the Bremont MB1
The Breitling Navitimer rotating bezel
Three time zones on the Rolex GMT Master II
The Clarity of the IWC Top Gun Dial

Since 2016 there has been an internationally recognised standard specification for pilot’s watches.  Launched in Germany, DIN 8330 was designed to ensure a very high standard of specification ensuring that the watch can be read quickly and accurately both during the day and at night, as well as being operated while wearing gloves.  It also established a standard for resistance to changes in temperature, resistance to shock and G-forces, as well as accuracy in a variety of changing conditions.

DIN 8330 also defines more precise criteria, including for vibration resistance, magnetic field protection, resistance to liquids commonly encountered in the aviation industry (fuel, lubricants, cleaning fluids and de-icer) and compatibility with night-vision equipment.

It’s interesting to see that all of the criteria defined 100 years previously made it onto the DIN 8330 list.

The first manufacturers to pass the DIN 8330 tests and produce certified watches were German brands Sinn and Stowa

Stowa Flieger Din Professional
Sinn 103 Ti
Stowa Flieger Din Professional

Our next instalment takes us away from war time and introduces the most famous postman ever…

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