WHAT IS A CHRONOGRAPH WATCH? A PILOT'S GUIDE

A chronograph is simply a watch with a built-in stopwatch. It's one of the most useful complications you can have on your wrist, and it has a long history in aviation. Here's how it works, how pilots still use one, and what to look for if you're buying.

How to use a chronograph

Most chronographs have two pushers beside the crown:

• The top pusher (usually at 2 o'clock) starts and stops the timer.

• The bottom pusher (usually at 4 o'clock) resets it to zero once it's stopped.

The large central seconds hand becomes the stopwatch, and the small sub-dials count the elapsed minutes and hours. One sub-dial usually shows the watch's normal running seconds. Layouts vary between models, so it's worth a quick look at the manual for your watch.

How pilots use a chronograph

In a modern airliner, the flight management computer does most of the timing. But plenty of us still start the chrono out of habit, and in light aircraft it remains genuinely useful:

• Holding patterns: the outbound leg of a hold is flown for a set time, typically one minute at lower levels.

• Navigation: timing each leg against your planned groundspeed is a quick check that you are where you think you are.

• Approaches: some instrument approaches are flown on timing from a fix.

• Fuel and engine checks: regular checks at set intervals, and timing items in the checklist.

On the ground, it's just as handy for parking meters, the oven and a 5K run.

What is a tachymeter?

A tachymeter is the scale printed around the bezel of some chronographs, including our Horizon Chronograph. It turns elapsed time into speed over a known distance.

Start the chronograph as you pass a marker, stop it after exactly one mile or one kilometre, and read the number on the bezel next to the seconds hand. That's your average speed per hour. Cover a mile in 20 seconds, for example, and the tachymeter reads 180: 180 miles per hour.

Quartz or mechanical chronographs?

Mechanical chronographs are wonderful but complex, and usually expensive. Quartz chronographs are more accurate, lighter and far more affordable, which is why all of ours use quartz movements.

Our AvGeek® and Horizon Chronographs use Miyota (Citizen) movements that time to the second for up to 11 hours, 59 minutes and 59 seconds. Our Swiss models use Ronda movements, rated at +20 to -10 seconds a month.

What to look for in a chronograph

• A clear dial. Sub-dials add detail, so a well-balanced layout and strong contrast matter even more than on a simple watch.

• The right size. Chronographs tend to be a little thicker. Try 38mm to 41mm if you have a slimmer wrist.

• Water resistance. 100m is ideal for everyday life, but don't press the pushers under water.

• The features you'll use. A tachymeter looks great and is fun to use; a date is handy every day.

Our pilot chronographs

• AvGeek® Chronograph (£199): 38mm and bold, in five colours plus limited edition Panda dials.

• Horizon Chronograph (£299): 41mm with a tachymeter bezel, date, sapphire glass and a steel bracelet.

• Aerobility (£199): a 42mm Swiss quartz chronograph with a teal dial, supporting Aerobility, the charity helping disabled people fly.

• Horizon Original (£199): our original 42mm Swiss quartz chronograph, in clearance while stocks last.

Weighing up a chronograph against a simpler watch? Read our guide to choosing a pilot watch, or browse all our quartz pilot watches.

Every FLYER® watch comes with free worldwide delivery, a 2-year international warranty and 14-day returns. Our watches support flying scholarships through Helping Dreams Take Flight, helping people of all ages and backgrounds into the air.

Frequently asked questions

What's the difference between a chronograph and a chronometer?

A chronograph is a watch with a stopwatch function. A chronometer is a watch that has passed a formal accuracy certification. A watch can be one, both or neither.

Does using the chronograph drain the battery?

On a quartz chronograph, yes, a little. Running it constantly will shorten battery life, so stop and reset it when you're done.

Can I use a chronograph under water?

You can wear a 100m water-resistant chronograph swimming, but don't press the pushers under water, as that can let moisture in.