Hainan Airlines Boeing 787 (photo: Boeing)
Thu 18 Jan 2018 – Belly freight carried in the cargo hold of passenger aircraft accounts for around 25% of the total payload mass moved on flights across the Pacific and is the most important driver of airline fuel efficiency performance. So finds a new study by the International Council on Clean Transportation (ICCT) which has analysed and ranked 20 airlines operating nonstop flights between mainland United States and East Asia and Oceania. It found the gap between the most fuel efficient, China’s Hainan Airlines and All Nippon Airways (ANA), and least efficient, Qantas Airways, was 64%, which is the widest it has found in its studies on comparing US domestic and transatlantic flights. Airlines that predominantly used Boeing 787 Dreamliner aircraft were also found to be considerably better performers on transpacific routes than those using four-engined aircraft, including the Airbus A380.
ICCT started assessing the fuel efficiency of US airlines on domestic operations in 2013 and then progressed to comparing 20 major airlines operating on routes between North America and Europe for the year 2014. The gap between the most and least efficient airlines on US domestic routes was 25% in 2014 and the gap on transatlantic routes was 51%. As would be expected, those airlines with more fuel-efficient aircraft, less premium seating, and higher passenger and freight load factors performed better.
However, the transpacific market differs in important ways, says ICCT. Twin-aisle and very large aircraft are prevalent on flights across the Pacific Ocean but are rarely used for US domestic operations. They are also used on transatlantic flights but more premium flight offerings are available for the Asian market, typically resulting in fewer seats on each plane. In addition, the amount of freight transported between Asia and the United States, both in dedicated freighter aircraft and in the cargo hold of passenger planes, dwarfs what is carried between the US and Europe.
ICCT assessed the key drivers of the fuel efficiency gap between the 20 transpacific carriers – aircraft fuel burn, seating density, passenger load factor and freight share of total payload. Of these, freight share was found to be the most important driver overall, accounting for almost half of the variation across the carriers, compared with just 9% for transatlantic flights. Seating density made up nearly a quarter of the variation, with aircraft fuel burn and passenger load factors relatively less important (see graph below).
Hainan and ANA both achieved an average fuel efficiency of 36 passenger-kilometres per litre (pax-km/L) of fuel in 2016, 16% better than the industry average, but by using very different strategies. Hainan achieved its efficiency rating through its very advanced fleet, with 81% of available seat kilometres coming from its Boeing 787 aircraft. In contrast, ANA operated aircraft with higher fuel burn but carried more payload, especially cargo. ANA carried three times as much belly freight per passenger as Hainan, equalling 48% of total payload carried.
Qantas, whose fuel efficiency fell 41% below the industry average on transpacific routes, was found by ICCT to operate the most fuel-intensive aircraft at very low load factors for both passengers and freight.
ICCT’s study found that in general the fuel burn per passenger-kilometre increases along with aircraft size and weight. Airlines that predominantly use the four-engined Boeing 747 and Airbus A380 – Asiana, Korean Air and Qantas – had the lowest overall fuel efficiency. In addition, the seating densities and passenger load factors on these aircraft were typically less than the industry average.
“There’s a reason airlines around the world are starting to avoid very large aircraft like the 747 and A380,” said Dan Rutherford, ICCT’s Aviation Program Director and co-author of the report. “Newer twin-engine widebodies provide the payload and range capabilities needed for transpacific flights with much lower fuel burn.”
The Boeing 777 aircraft family was the most widely used on transpacific routes in 2016, accounting for 57% of all flights, and its overall fuel efficiency averaged around 1 pax-km/L better than the industry average. The Boeing 787 and Airbus A330-300 were notably more fuel efficient at 35 to 39 pax-km/L, although the newest twin-aisle aircraft on the market, the Airbus A350-900, with a fuel efficiency measured just above average, did not perform as well as might be expected given its technology level. However, the A350 made only a small number of transpacific flights in 2016, just 280, and ICCT expects its average fuel efficiency to improve as more airlines fly the aircraft at higher passenger load factors and freight share.
As similarly observed in ICCT’s transatlantic rankings, seating configuration – or seating density – also influences airline fuel efficiency. The seating densities on transatlantic operations were found to be generally higher than for transpacific operations, with a higher share of premium seats (first and business class) for transpacific flights. Given that premium seats are on average three times as carbon-intensive as economy seats, this could be one explanation for why average fuel efficiency for transpacific operations at 31 pax-km/L was lower than for transatlantic operations at 32 pax-km/L, suggests ICCT.
“This research shows that there are a variety of ways that international airlines can reduce fuel use and carbon emissions,” commented ICCT’s Brandon Graver, lead author of the study. “Buying new aircraft, carrying large numbers of passengers and optimising freight strategies all make a difference.”
ICCT said future work will be undertaken to quantify and compare the difference in the amount of fuel burned to transport a tonne of freight across the Pacific by way of a dedicated freighter compared with using passenger aircraft freight capacity. It also hopes to include routes to and from Canada in future rankings and is seeking widespread cooperation from ranked airlines so that its methodology can be shifted from a modelling approach to one which uses primary fuel burn data.
Fuel efficiency of 20 airlines on transpacific passenger routes in 2016 (source: ICCT):
Difference from industry average fuel efficiency of 31 pax-km/L for 14 aircraft types used on transpacific routes in 2016 (source: ICCT):
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