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02
Tue, Jun

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This week I was asked by Vance about helicopter emissions. Recently Astrum Helicopters announced that they will be offering helicopter adventures and direct helicopter transfers to Chaa Creek, an award-winning eco-resort in Belize. To my reader it seemed contradictory to the mission of a Green Globe benchmarked resort to use helicopter transportation due to the potentially harmful effects of greenhouse gas emissions and noise pollution. But how bad is it really? Read on to find out...

Chaa creek is about 1.5 hours away from the airport by road, or an estimated 130 km. By air the distance is less, about 94 km. Would the savings of 80 km per round trip be worth the increased fuel consumption of the helicopter? Well, let's find out how much it is first. The helicopter in question is a Bell 206 L4, with a range of 615 km on 419 liters of aviation turbine fuel (Jet A). 419 l per 615 km comes out to 1.47 km/l, or 3.46 mpg. This aircraft will carry four people, with luggage, and we will assume the same for the airport van. The airport van probably gets around 15 mpg, or 6.4 km/l, so we can already see that the van would be over 4x more efficient over the same distance. Since the helicopter flies a direct line we will need to take that into account as well. Over the 94 km distance the helicopter will burn about 64 liters of fuel whereas the van will burn just over 20 liters. So, despite the distance saved the helicopter will use more than 3x more fuel than the van.

How does this compare to other transportation modes? Well, unlike shipping emissions, which are based on g/tkm (grams of GHGs per tons transported times distance transported), human cargo is measured in kg/100pkm (or kilograms of GHGs per 100 passenger kilometers. This takes into account the number of passengers, but not the crew, and helps us compare different aircraft and fleet emissions on a per-customer basis. Our helicopter transports 4 people over 615 km with 419 liters of Jet A fuel. The GHG emissions from Jet A are similar to gasoline, at around 3 kg per liter (See AskPablo: The Tailpipe Mystery), so 419 liters would result in 1,257 kg of GHGs. This needs to be adjusted form our passenger-kms of 2,460 (4 people x 615 km) to 100 pkm. So we divide 1,257 by 24.6 (2,460/100) to get 51.1 kg/100pkm. The van, for comparison is 11.7 kg/100pkm. In Lufthansa's 2005 Corporate Responsibility Report they reported a fleet-wide emissions level of 11.1 kg CO2 per 100pkm. This can be adjusted for the Radiative Forcing Index for aviation emissions by multiplying by 2.7, to get 30 kg GHG per 100pkm.