Montre d'Aeronef Type 20

“I am very satisfied with the Zenith watch, which I usually use, and I cannot recommend it too highly to people who are looking for precision,” said Louis Blériot on March 19, 1912. His Zenith watch sported a luminous dial and hands for optimal readability, and also had a crown that was easy to manipulate while wearing gloves. A seconds counter at 6 o'clock provided additional temporal information.

From 1939 onwards, the Zenith Montre d'Aéronef Type 20, with its 36-hour power reserve, was standard equipment on most French planes. Lauded by aviation builders and professionals for its reliability, sturdiness and accuracy, it appeared on the instrument panels of many airplanes, in particular the Caudron Simoun C.635 models used by the French Army for training and by the Air Bleu postal company for international and transatlantic routes.

Its case, made of a light alloy, could be attached to the instrument panel and included an easy-to-handle knurled bezel for winding and setting the watch. The dark dial was ringed with heavily-coated luminous numerals, giving the important criterion of visibility its due. The small seconds dial was at 6 o'clock, while the equally luminous hour and minute hands left no doubt as to the time displayed.

The mechanical movement had a bimetallic balance wheel coupled with a selfcompensating, anti-magnetic hairspring and a Swiss lever escapement – all solutions that met aviation's need for reliability and accuracy.