Final answer:
NOTAM Authorities should use plain language and ICAO approved contractions as outlined in ICAO Annex 15 and ICAO Doc 8400 to clearly communicate NOTAM conditions.
Step-by-step explanation:
When using free text, NOTAM Authorities should use both plain language and ICAO approved contractions to clearly express NOTAM conditions, which are outlined in the ICAO Annex 15 and ICAO Doc 8400, also known as the ICAO Abbreviations and Codes. These publications provide guidance on the standardization of phrases and abbreviations to ensure clarity and understanding amongst aviation professionals worldwide.
The ICAO approved contractions are designed to communicate information efficiently and effectively, while plain language ensures that the NOTAM can be easily understood by those who may not be familiar with the contractions. By utilizing both approaches, the NOTAM conditions can be communicated with precision without sacrificing the accessibility of the information for a wider audience. This is vital for maintaining safety and efficient operations within the aviation industry.