The present document specifies the minimum technical requirements for maritime two-way AM VHF radiotelephone pparatus for communications between ships in distress and rescuing aircraft. The standard incorporates relevant provisions of the ITU Radio Regulations , of IMO Assembly Resolutions  and of Annex 10 to the ICAO Convention . The maritime VHF equipment described in the present document is intended for communications on the aeronautical emergency frequencies 121,5 MHz and 123,1 MHz only. The present document is applicable to portable and fixed installed equipment. The intention of the present document is to define equipment that in all respects have mechanical and electrical design, construction and finish in conformance with good engineering practice and that is suitable for use on board ships at sea in distress situations.