180 YEARS OF

AVIATION | Longines Twenty-Four Hours
58 | WatchTime LONGINES SPECIAL
ON A SINGLE DIAL
In the 1950s, Longines
created a special watch for
the navigators of Swissair.
ese days, on-board ight computers calculate the path
from one place to the next. ey get their information
from the Global Positioning System (GPS), from various
radio beacons on the ground and from the Inertial Navigation
System (INS). Together these systems supply the
Flight Management Computer (FMS) with all the necessary
data required to calculate the correct ight path.
Before departure the entire route is entered directly into
the FMS or sent via laptop. e two-man crew can then
concentrate on their duties during the ight and y the
airplane or simply check the controls, depending on the
segment of the ight. Exact time in the cockpit these
days is supplied by the GPS and an independent digital
clock. And the pilots of the military forces always wear a
specic type of watch during dicult missions to serve
as an additional backup if necessary.
Like its predecessor:
The new Longines
Twenty-Four Hours
also has an onion
crown and a
central seconds
hand (far left).
The hinged back of
the replica model
covers the automatic
Cal. L704.3.
Many years ago cockpits looked very dierent than
they do today. In the absence of today’s powerful computers,
work in the cockpit was distributed among three
people: the captain, the copilot, and the navigator who
sat behind the two pilots in an area full of displays and
controls. e duty of the navigator was, as the name indicates,
to navigate. He was also a kind of on-board technician
who monitored many of the systems that are now
controlled by computers. e navigator also ensured
that fuel was pumped from one tank to another for optimized
trim of the airplane. e navigator was primarily
concerned with ight preparation and execution. He
calculated and continuously checked the course of the
airplane with all his various tools and instruments and
he collected any available data from radio beacons and
navigational aids on the ground.
During a long-distance ight an airplane may y
through numerous time zones whose times dier from
the UTC. e standard time must, therefore, be the same
in every cockpit. Earlier GMT (Greenwich Mean Time)
was the standard time; today it is UTC (Universal Time
Coordinated) in both air and sea travel. ere is also no
dierence between civilian and military time. Both base
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