Flyback chronograph
Stops, resets, and restarts in a single pusher press
What it is
A flyback chronograph is a variant in which a single pusher press; while the chronograph is running; simultaneously stops, resets, and restarts the timing in one mechanical sequence. A standard chronograph requires three separate actions to achieve the same result: stop, reset, restart. The flyback mechanism collapses these into one press, which matters in aviation where measuring consecutive legs of a flight leaves no time for multiple pusher operations.
History
The flyback was developed for aviation timing in the 1930s. Breguet, Longines (caliber 30CH), and Heuer all produced flyback chronographs for the cockpit market. The IWC Mark XI (1948) and the Breguet Type XX (1955) are the canonical aviation flybacks. Modern references include the Breguet Transatlantique Type XXII, Patek Philippe 5170P, and the Lange Double Split, which adds flyback capability to a split-seconds mechanism.
How it works
When the flyback pusher is pressed while the chronograph is running, a flyback lever acts on the column wheel and hammer simultaneously, sequencing stop, zero, and restart faster than the operator can perceive. The lever must perform all three actions in the correct order; stop before zero, zero before restart; within a fraction of a second. The result is that the seconds hand snaps to zero and immediately begins counting again.
Parts required
Standard chronograph components plus a flyback lever that sequences the stop-zero-restart actions from a single push input, typically a pivoted lever acting on the column wheel and the reset hammer simultaneously
What makes it difficult
The three actions; stop, reset, restart; must occur in the correct sequence within a fraction of a second. If the restart happens before the zero, the hand jumps forward from its stopped position rather than returning cleanly to zero. If the stop happens after the zero, the elapsed count is disrupted. The tolerance stack in the flyback lever is smaller than in a standard three-action chronograph, and the mechanism must perform reliably across decades of use.
In the catalog
Related
- Chronograph: A stopwatch complication; start, stop, reset
- Rattrapante: A split-seconds chronograph; two independent timing hands
