The Helicopter Air Ambulances (HAA) industry continues to expand. In response to the dynamic growth of this industry, the Federal Aviation Administration (FAA) has issued this advisory circular (AC) to provide information and guidelines to assist existing HAA operators, other Title 14 of the Code of Federal Regulations (14 CFR) part 135 operators considering becoming an HAA operator and those considering new-startup HAA operations. To address an increase in fatal HAA accidents, the FAA has implemented new operational procedures and additional equipment requirements for HAA operations.