scope:

To ensure the regularity and safety of aviation, it is necessary that aero- drome lighting and radio navigational aids have high integrity and reliability . It is considered that the probability of failure of well designed and maintained lighting and radioaidsatacritical moment is extremely low.

The following material is intended as a guide to the recommended electrical engineering practices for design and installation of new systems and the modification of existing systems of aerodrome fixed lighting and of distribution of power to radio navigation aids. It does not imply that existing installations , if different , are wrong and should be changed automatically. It does mean that some of the earlier designs adopted are not recommended for repetition since they have been superseded by later thinking. Because of the differences in engineering style and equipment indifferent countries , this material establishes only basic design principles. It is not intended to illustrate detailed design or particular pieces of equipment or systems unique to any one State.

The electrical systems for aerodrome visual aids and navigation systems require good quality installations and consideration for features which are not usually involved in other electrical installations . This manual discusses the general features of electrical practices and installations with emphasis on those features which are less commonly involved or have special significance for aerodrome operations. It is assumed that those using this manual will be familiar with electrical circuits and general practices but may not be knowledgeable of certain features of aerodrome installations which are less frequently encountered in other electrical system. Some of these features are that mast eIectrical circuits are installed underground, series circuits are used for most lighting systems, higher reliability is required of the input power sources, and rapid, automatic transfer to secondary power i n case of power failures. Each aerodrome i s unique, and its electrical installation should be designed to provide economically power and control which is safe , reliable , and easily maintained.