Paragraph 1 F1F2

The light signal, consisting of a flashing blue light as defined in the Airworthiness Technical Manual of the International Civil Aviation Organisation (ICAO) Doc. 9051, is established for the use of medical aircraft to signal their identity. No other aircraft shall use this signal. Medical aircraft using the flashing blue light should exhibit such lights as may be necessary to make the light signal visible from as many directions as possible.