Gro?e Fliegeruhr. The Big Pilot Watch.

The Gro?e Fliegeruhr was a military issue watch for use by Aviators. The large cased watches were referred to as “Nav B-Uhr” or “Beobachtungsuhr” (Navigation Watch).


IWC Big Pilot Watch (reference IW500401)


This specification of watch supplied to the Luftwaffe was dictated by the RLM (Reichsluftfahrtministerium), the German Ministry of Aviation (the RLM operated from 1933 – 1945).


Five manufacturers made watches to the specification dictated by the RLM; Lange & Söhne, Laco (Lacher & Co), Stowa (Walter Storz), Wempe and IWC.


The watches had a case diameter of 55mm, were marked on the back with FL23883 and were equipped with large winding crowns to facilitate operation whilst wearing gloves.


Additional features included a hacking movement (ability to stop the second hand when pulling out the crown), Breguet balance spring, chronometer certification and a long leather strap to allow the watch to be worn over a flying suit.


The strap typically featured two decorative rivets on each side, near the shoulders of the watch case (four in total).


The watch was fitted with an anti-magnetic casing to protect the movement against magnetic fields.  A triangular shaped index at 12 O’clock would feature on the dial with two dots either side, as required by the RLM.


IWC shipped 1000 pieces to Siegfried Heindorf, Berlin in 1940 and these have become incredibly sought after with high values being achieved at auction. In 2006 a model sold at Christies in Geneva for CHF 48,000.


The case

The case of the modern Big Pilot by IWC is 46.2mm in diameter, which is markedly smaller than the original Gro?e Fliegeruhr (55mm) typically worn by Bomber pilots during World War II, albeit still considered a large watch, especially with its oversized crown.


IWC Big Pilot Watch (reference IW500401)


The case is stainless steel but contains an inner core of soft-iron to protect the movement from external magnetic fields.


IWC Big Pilot Watch (reference IW500401)

IWC Big Pilot Watch (reference IW500401)


The crown is unusually large, dating back to its wartime origins when adjustment would take place whilst the wearer wore gloves. The onion-shaped crown has a fluted pattern and bears the text “Probus Scafusia” (good, solid craftsmanship from Schaffhausen), the motto which adorns many of IWC’s movements.


The movement

The Big Pilot of today incorporates a rotor which provides automatic winding of the mainspring, whereas the original Gro?e Fliegeruhr was a manually wound watch.


The current watch contains the Calibre 51111 incorporating 42 jewels.


The watch has a 7-day power reserve when fully wound. It  can store up to 8.5 days of power, however, only 7 days of energy is used before the movement is stopped prior to the tension in the mainspring approaching full exhaustion and the accuracy of the watch being compromised.


The dial

A notable departure from the original Gro?e Fliegeruhr is the presence of a power-reserve indicator.


IWC Big Pilot Watch (reference IW500401)


The dial does share the triangular index at 12 O’clock with two dots and has the type face and markings typically used in 1940.


A further modification from the original watch is the presence of a date window which did not feature in the original RLM specification.


The strap

The black alligator leather strap is a deviation from the original brown buffalo leather which I must admit I prefer and will adopt when the strap requires replacing.


IWC Big Pilot Watch (reference IW500401)


The deployant helps the strap sit comfortably on the wrist and reduces wear when contrasted with a pin buckle.


The decorative rivets of the original have been faithfully replicated and add to the visual appeal of the watch.



The IWC Big Pilot is a wondrous watch to behold. It’s similarity to the original is obvious but with the convenience of an automatic movement, date and power reserve indicator.


The clarity of the dial with hands, colour, numerals and indices, faithful to the original specification dictated by the Ministry of Aviation remains applicable to the current day, aiding immediate interpretation.


IWC Big Pilot Watch (reference IW500401)


I marvel at the clinical movement of the second hand and the multiple integers it passes though each second.


The imposing size of the Big Pilot suits this tall gentleman and whilst I am unlikely to wear the watch over a flying suit, the large dimensions are congruent with my own physique.

Whilst the watch is large and very visible, the reader should not confuse this with brashness or vulgarity. Its form is stylishly simple and continues to remain a relevant design over 70 years since Herr Heindorf received the original 1000 timepieces from IWC.


Gro?e Fliegeruhr. Big Pilot. A wonderful design borne out of practicality with an aesthetic beauty I will never cease to admire.

Related Links

Subscribe to our newsletter

Stay up to date with the latest post and updates

Subscribe to our Newsletter

Give us your consent