This is a very rare stainless steel Mark 11 made by Jaeger-LeCoultre (JLC) for the Royal Australian Air Force (RAAF) circa 1955. Mark 11s were manufactured by IWC and JLC based on specifications provided by the British Military Defense (MoD) in 1948. Before being issued for service, all watches had to endure rigorous performance testing at the chronometer workshop of the Royal Greenwich Observatory, where they were regulated to five positions and various temperatures over a two-week period. To maintain optimal operation, watches had to be retested annually, regardless of whether or not they were issued. Mark 11 is branded with a broad arrow on the case, and movement to denote government property.
Of the 2000 Mark 11s produced by JLC, approximately 50 are known to have the number 12 on top of the dial rather than the luminescent triangle, making our example in this pristine condition the Holy Grail of the Mark 11s. This watch is documented on the databases gathered and published online by experts such as Zaf Basha.
This watch features a chronometer grade, manual caliber JLC Caliber P488/SBr movement, with 17 jewels, fitted with a spirale Breguet. The case is antimagnetic. In keeping with the commission of the watch as a functional tool for military aviators, the movement is not decorated, but it exudes an emphasis on durability and accurate time keeping rather than fine finishes and cosmetics.
The caliber was produced in a low production run of about 2,950, and its formidable design was the basis for the Cailber P478/BWSbr used in the iconic 1958 JLC Geophysic.
This timepiece comes with sharp lugs and minor surface wear – no deep scratches or dings. The printed numerals and markers are original, as are the luminous radium hands and the crown. Due to age, there is a small amount of paint loss across the manufacturer’s signature that should be left alone. The dial of the Mark 11 was designed to lock in with an iron back to make the watch anti-magnetic. Many Mark 11 dials show rust from the iron back coming through the dial paint. Other than the slight paint loss, the dial on this example is near mint.
Case size is approx 35.5 mm
