By Bob Rogers, President, Nordisk Aviation Products Asia
Far too many years ago when I first started working in the ULD industry, with the 747’s, DC10’s and L1011’s just starting to take their place in the fleets of Asia Pacific’s airlines, a typical LD3 container weighed around 135 kg. Before long the airlines were facing yet another oil crisis (maybe US$20 a barrel oil oh happy days) and tech services departments started to pursue the weightreduction chase.
The first steps downwards took an average LD3 to around 100 kg, mainly through better design, which enabled strength to be maintained or even increased while the weight came down, with the added bonus that with less aluminium, cost also came down.
After a lull of a few years with relatively stable oil prices weight again raised its ugly head as airlines sought to fly increasingly long non-stop flights, and the tare weight of a typical LD3 fell to around 75kg. At this weight the designer has little latitude, he has to maintain a structure that is strong enough to pass the certification tests listed in NAS 3610, create a structure that will not be susceptible to racking or twisting when carrying loads, and yet is only 75 kg, using just aluminum. Below 75 kg one has little choice but to move into alternative materials, and here it gets hard.
Of primary concern must be cost. Yes, it is possible to find super lightweight materials such as CFRP, but airlines will balk at the cost of buying a US$2,000 LD3, especially as at any point in time only about 20 percent of an airline’s LD3 fleet is in the air, the rest are sitting on the ground and are not saving the airline any money at all.
Then of course there is the same old question, what will happen to the damage costs, especially as in most airlines the benefits from weight savings show up in the fuel budget, while the costs of any additional maintenance fall on the shoulder of the ULD control dept. There are however compelling arguments to lower the weight of any aircraft and if an airline can achieve this by reducing the weight of its LD3’s then surely nothing should be allowed to stand in the way, because the benefits are clear: First of all, how much weight can be saved by using lightweight ULD.
It now seems possible to move down from the current 75 kg lowest aluminum LD3 to units in the mid 60’s by using a combination of composite materials for the side and roof panels while retaining a basic structure of aluminum. Composite base sheets remain a distant possibility at this time.
If one takes a typical wide body configuration at 14-16 LD3 then a 9-10 kg saving will give around 150 kg aircraft weight reduction. Obtaining accurate and reliable figures on the amount of fuel saved per aircraft per year is not easy, but figures used in an IATA presentation indicates that a weight saving of 1 kg per seat saves around 9,000 gallons of fuel per aircraft per year, from this we can deduct a fuel burn saving per kg of weight saved is 30 gallons, at the time of writing the price of a gallon of jet fuel is $2.00, so a saving of US$ 60 per kg per aircraft per year. This figure will of course vary according to the fleet mix and the route structure, but it’s a good guide.
Airlines may have a number of different motivations to pursue a fuel cost saving programme. Its safe to say that all airlines have a general concern about fuel costs, and thus are looking for ways to cut these costs. However some have more reason to pursue this ambition than others. Ultra long haul flights are clearly extremely weight sensitive and often weight restricted and any saving in ULD weight can make the difference when it comes to adding one more passenger on a weight restricted flight.
The A380 is another driver, as with any new aircraft type there are concerns regarding the operating performance of the aircraft, not to mention the issue of weight added in the passenger cabins through in-flight entertainment etc. And, most recently is the issue of the environment. Airlines are suddenly in the front line when it comes to controlling carbon emissions and carbon emissions are directly linked to fuel burn which is directly linked to aircraft weight.
Airlines cannot pass up any opportunity to reduce emissions, and lighter weight ULDs is one obvious course to take. Most airlines expect their containers to last around 10 years, some less, some more, so any decision to purchase a particular specification of ULD today will remain in the fleet for 10 long years. This makes it all the more important that airlines start today to look critically at ways to cut weight out of their ULD fleet, contributing to both their bottom line and the environment at the same time.
Some 25 years ago a typical LD3 weighed 130 kg. Maybe 25 years from now the average LD3 will weigh 65 kg, but airlines need to start on the path now, the previous steps into the unknown have proven successful and saved airlines millions of dollars. It’s time to make the next step.
