Even though GPS and computers do all the work today, student pilots are still taught to calculate speed the old-fashioned way, by timing how long it takes to fly between section lines, or to know how long to maintain a standard rate turn in order to turn 180 degrees (one minute). As on the sea, accurate timekeeping is essential when navigating by air.
In my day the Air Force issued watches like this to student pilots and navigators. They were mechanical, requiring winding once or twice a day, with 24-hour dials and hackable sweep-second pointers. Some wore issue watches throughout their flying careers; many, like me, replaced them with fancier watches and chronographs we bought with our own money. Even though I didn’t fly with it for long, I hung onto my issue watch for many years, but somewhere along the way it disappeared and I no longer have it.
Not that any of us ever paid attention to this particular regulation, but the FAA and the military have always mandated a clock (displaying hours, minutes, and seconds with a sweep-second pointer) for instrument flight. A clock in the cockpit, that is, mounted on the instrument panel where it can be clearly seen. Wristwatches, no matter how pricey, do not meet the requirement.*
I have a confession to make: even though I wore one, I never once used a wristwatch to time anything in flight. I always used the clock that came with the aircraft. This clock:
And it wasn’t because I was aware of the regulation prohibiting the use of wristwatches for timing in instrument conditions. It was because the clock on the instrument panel was big, easy to read, and positioned so you could reach out and hack the timer button with your finger. These too, like our issue watches, were mechanical: fully wound they’d run for eight days, and being mechanical, even with total electrical failure you’d have a clock. I understand the FAA and the military have modified the rules to keep up with the times: electrical clocks with backup battery power, usually with digital readouts, have replaced mechanical clocks in new aircraft. Wristwatches, though? No change there that I’m aware of.
If you look closely, you’ll see the mechanical clock on this F-15A instrument panel. It’s on the bottom, just to the right of the trim button on top of the control stick.
*So if clocks are required in all aircraft and regs say we’re not supposed to use our wristwatches, why did the Air Force give us watches? The answer, I honestly believe, was so we’d have something to do during the preflight briefing when lead told us to sync our watches.