The operation of scheduled night flying presents two tasks to aviation:—

• (1) The technical task of taking off from and landing on an aerodrome.

• (2) The operation of the flight from one aerodrome to the other.

The first task presents no completely new problem, as sufficient experience was gained during the war. All that was necessary was to provide facilities which guaranteed regular traffic.

The second task was purely one of navigation. It had to be solved in accordance with the strict demands of maximum safety and maximum regularity of the service. The only means of navigation then available, the compass, was not sufficient for these requirements, and at night it was not possible to count on keeping on the course by observing objects on the ground.