The glossary of movements and parts has the basic terms, but one function keeps coming up in QC questions: the flyback. One example of an original with this function is the Royal Oak Chronograph 26240ST. Audemars Piguet lists the functions of its Calibre 4401 as “Flyback chronograph, hours, minutes, small seconds and date”.
The questions: what exactly does a flyback do, and how do you check it on a rep?
[[PHOTO: Schema eines Chronographen mit zwei Drückern, der obere beschriftet mit „Start/Stopp“, der untere mit „Nullstellung (beim Flyback auch während der Messung)“]]
Editorial summary, not independently verified.
The difference in a few words:
- Regular chronograph: start, stop, reset, then start again. A new measurement takes three presses.
- Flyback: while the chronograph is running, pressing the reset pusher sends the hands to zero, and on release the timing restarts immediately. One press instead of three.
The name comes from the hand “flying back” to zero and running straight on.
Newbie question: isn’t that the same as a rattrapante? And can you just press reset during timing on any chronograph?
No and no:
- A rattrapante (split-seconds chronograph) has a second seconds hand that can be stopped while the other keeps running, to time intermediate splits. That is a different function from the flyback.
- On a chronograph without flyback, resetting while timing is running is not intended. Depending on the movement, the pusher is then locked. You shouldn’t force it.
Important for QC: before such a test, find out whether the original has a flyback function at all. On a model without flyback, it is not a fault if reset doesn’t work during timing.
You can only check it with a video, not with photos. A short sequence:
- Start the chronograph and let it run for a few seconds.
- While it’s running, press and hold the reset pusher: all chronograph hands should jump to zero.
- Release: the timing should restart immediately.
- At the end, stop and reset normally.
Watch whether the hands sit exactly on zero and whether they restart cleanly, without hesitating.
[[PHOTO: drei Einzelbilder aus einem QC-Video: Chronograph läuft bei 12 Sekunden, Zeiger auf null bei gedrücktem Drücker, Zeiger wieder bei 1 Sekunde nach dem Loslassen]]
And if the hands don’t sit exactly on zero after the flyback? Is that the same problem as with the normal reset?
Basically yes: a hand that stops next to zero is a reset adjustment problem. It then usually affects the normal reset too. What is normal and what isn’t is in the thread on chronograph hands not returning to zero. How to check winding, hacking and power reserve when unboxing is in the arrival check for rep watches.
A photo only shows that there are two pushers. Whether the movement has a flyback, how well the reset works or how accurately the watch runs can’t be seen in a picture.
Summary:
- Flyback: while timing is running, the reset pusher sends the hands to zero, and on release the timing restarts immediately.
- Regular chronograph: stop, reset and start are three separate steps. Resetting during timing is not intended and can be locked.
- A rattrapante is something else: a second seconds hand for splits.
- Before testing, find out whether the original has a flyback (example: AP lists it for Calibre 4401 of the 26240ST).
- Check by video only: start, reset during timing, release, clean restart.
- A photo proves neither the flyback nor the timekeeping.
Editorial summary, not independently verified.
Thanks. Point 4 is the most important one for me: first check whether the original even has the function, then test.