The helicopter most commonly used for helicopter sightseeing flights is of the type Robinson R44 with a 6-cylinder piston engine from Lycoming. The consumption is around 55 liters of aviation fuel (AVGAS) per flight hour. The combustion of 1 liter of avgas generates about 2,3kg of CO2 – a 20-minute sightseeing flight with 3 passengers + pilot in the R44 generates an estimated 42,17kg of CO2. So 14kg CO per passenger2.
For comparison: a Bell 206 “Jetranger” turbine helicopter requires 100 liters of kerosene per hour. The combustion of 1 liter of kerosene generates about 2,53kg of CO2 – a 20-minute sightseeing flight in a Jetranger therefore generates an estimated 84,33 kg of CO2. Because the Bell 206 has space for the pilot + 4 passengers, there is one CO per capita for a 20-minute round trip2-Load of 21,08kg per passenger.