FLYBACK complication “stops”, “resets” and “restarts” a stopwatch with only one pression on a command. Usualy, 3 commands need to be activated. This video shows you an HEUER ref. 918 dec. stopwatch with flyback complication.
This complication was developped by LONGINES in 1936 to help pilot aircarft to time quickly duration, while they were busy by many other manipulations in the cockpit.
Flyback is also a great adavantage to time quickly a serie of durations.