If you have a Jaeger LeCoultre clock you need
serviced, you will find services and charges listed on the Aircraft Clock
Restorations and Repair Services page.
the Hamilton and Elgin 37500 Elapsed Time clock, the USN and US Army Air
Corps specified the Jaeger LeCoultre A 10 Chronoflite. This clock is
seen with dataplates for both services as well as in RAF/Air Ministry
markings. After the US entered WWII, military timepieces from Switzerland
became unavailable, spurring the War Department to require US
manufacturers to create similar or better timepieces. The most
famous example being the Hamilton M21 Ship Chronometer used for
navigation which replaced the USN's pre war contracts for the Swiss Nardin
These clocks are very difficult to
find, especially with US military markings. They were used more
extensively in RAF bombers are generally found with
"Smiths" ( a British vendor) on the dial. Although
infrequently found, they seem to show up in USA AC USAAF and USN Beau. Aer.
markings equally. They also appear in USAF markings and were
specified into the 1950s after Hamilton ceased its war production of the
37500 in 1945 and the assembly line was disassembled.
instruments were provided with three grades (Elapsed Time; Elapsed Time
with 60 minute Center Seconds Chronograph, and Elapsed Time, Center
Seconds Chronograph with Civil Date Function). All configurations
have a large 2 3/4 inch dial opening. The USN seems to
have predominantly used the most complicated clock while the Air Corps preferred
those without the Civil Date function. In addition these clocks
were provided with either a 24 hour dial (USN) and 12 hour dial (USA
Finally, Pan America used the Civil Date LeCoultres in the Clippers and
other airlines of the preWWII era likely used the LeCoultre clocks as
most aircraft clocks and any watch, the Swiss A 10 (which include the
Breitling Wakmann) wind "backwards" and have no provision for
reversing the winder. Every other clock and all watches include a
clutch which prevents damage if the winding knob is reversed. It
is not unusual to find that a Swiss A 10 has a broken winding wheel.
Whether it is because crew could not judge their strength with heavy
gloves before realizing they were reversing the knob, or that the clock
fell into the hands of those unfamiliar with their operation will never
Some attempt to "repair"
this damage by "letting in" new steel teeth. There are
times when this approach is appropriate on historically important and
rare clocks in which the primary goal is to conserve every individual
piece. But when we encounter this in aircraft winding parts, we
make the required wheel or click out of steel as needed.
The process for making winding wheels is presented on the
Making a Replacement Winding Wheel
is one example of where it is our unique combination of skills and
interest enable us to serve the Warbird community.
than the winding, these clocks provide many of the same features of the
Hamilton and Elgin 37500 clock. However, they include a feature
unique to the A 10. Unlike any other Elapsed Time clock, the Swiss
A 10 (and its copy Russian "Mig" clocks) allow the crew to
pause the Elapsed Time recorder with a knob at the midline of the
clock. This enables the crew to stop the ET recorder, for example
when parked at an airfield during refueling. In this way they can
track Time of Trip without totaling the sum of the individual flight
These clocks use a single mainspring and
the damage from mainspring breakage is not an issue. At present we have
not found it necessary to have unbreakable springs custom made for these
clocks. However, we will have a run made when our stock of springs
These are the most expensive
clocks we regularly offer because of the low survival rate of these
timepieces. Available in RAF, USN, USAAF and USAF markings.
$1300 to $1700 depending on dial and hand configuration. Because
of the variability in configurations, call or email for photos of clocks
that are currently available.