Michigan Compiled Laws, Chapter 259. Aviation § 259.5

(a) “Hazards to air navigation” means any obstruction of whatever character, object of natural growth, or use of land, upon or surrounding or adjacent to an airport, landing field, or other aeronautical facility, that prevents the safe use of the facilities for the take-off or landing of aircraft.

(b) “Heliport” means an area of land, water, or a fixed structure used or intended to be used for the landing and takeoff of helicopters or other rotary wing aircraft.

(c) “Heliport approach surface” means an imaginary plane beginning at the end of the heliport landing area with the same width as the landing area and extending outward and upward for a horizontal distance of 4,000 feet where its width is 500 feet. The slope of the approach surface is 8 to 1.

(d) “Historic aircraft” means an aircraft that is over 30 years old and that is owned solely as a collector's item or for participation in club activities, exhibitions, tours, parades, or similar uses, but that is not used for general transportation.

(e) “Hospital” means that term as defined in section 20106 of the public health code, 1978 PA 368, MCL 333.20106.

(f) “Hospital heliport” means a heliport limited to serving helicopters engaged in air ambulance or other hospital-related functions.

(g) “Hospital helistop” means a minimally developed facility for the boarding and discharging of helicopter crew and passengers and the loading and unloading of helicopter cargo solely for an air ambulance or other hospital-related functions.

(h) “In-flight” is that time from the beginning of an aircraft's take off run to the end of the landing run.