1. (1) Survey of the present methods of carrying out air transport service when visibility is bad.

2. (2) What is essentially required of technical aids for landing under bad weather conditions.

3. (3) Short survey of current German methods for solving the problem of landing in fog.

The necessity for being able to carry out air transport unhindered by weather conditions is inseparably associated with the idea of commercial air service. This great problem of “ flight in any weather ” has confronted us since the inception of regular services between places having corresponding traffic needs, that is to say, since the very birth of air transport.

It is possible to trace, in the flying equipment of birds, feathered versions of many of the refinements that render the modern aeroplane more efficient than its predecessors. It would, therefore, be a mistake to ignore birds as a guide to possible future developments. One of the most interesting groups of birds is that which includes all the owls, for there is a possible connection between the manner in which their strikingly silent flight is achieved and the increasingly pressing problem of silencing airscrews.