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Less burn, less cost

Weight & Balance

Fuel cost runs at more than 30% of airline operating expenses and it’s rising. New innovative IT can deliver savings with a vital bottom line impact.

Two thirds of airlines state that cost reduction is the number one driver for their IT investment. So says SITA's Airline IT Trends Survey. With fuel being a major expense, if airlines can burn less of it they stand to reap all-important cost savings.

Modern aircraft like the A320 family and Boeing 737 Max can be 15% or so more fuel efficient than their predecessors.

Yet despite fuel efficiency improvements due to engine design, lighter weight materials and better aerodynamics, fuel still accounts for a huge chunk of operating expenses – up to 30% today from around 17% in 2004.

For airlines in countries with lower labor costs, that can be a massive 40%.

Big impact

In 2013, airlines spent around $211 billion on their fuel. The jet fuel price index, set at 100 in 2000 now stands as high as 329. It would be a brave person who bet against further increases.

So with airline net profits at around only 3% of revenues, even a small decrease in fuel usage can have a big impact on the bottom line.

“That’s why it’s vital airlines and ground handlers pay the utmost attention to managing the aircraft’s weight and distribution of payload,” says SITA’s Allison O'Neill, VP Passenger Solutions.

“Next generation IT is paving the way, enabling aircraft to fly more efficiently and cost effectively than ever before. At the same time, there’s no compromise to safety,” she adds.

Balancing act

Airlines know only too well the effect of excess weight on fuel burn. But is the impact of aircraft balance as widely appreciated?

Consider the aircraft’s center of gravity. It’s the point where the aircraft would balance in all directions if it could be suspended from that point, and it must stay inside the aircraft's designed limits to ensure safety and efficient fuel consumption.

“Where that center of gravity rests is vital to obtaining the ideal trim position, which optimizes aircraft balance in flight – reducing drag, improving lift and enhancing fuel burn efficiency,” says SITA’s John Gayton, Product Manager for Horizon Weight & Balance.

According to Boeing, a 1% reduction in drag will reduce annual fuel burn for one B737 by up to 45,000 kgs for every aircraft each year.

‘aft sweet spot’

Coming into equation is the importance of ‘aft’, meaning ‘towards the aircraft’s tail’.  An aircraft loaded so that its center of gravity is near its aft limit uses less fuel than one where that center is further forward.

“With a more aft center of gravity, you can hit the sweet spot in terms of fuel efficiency, so the aircraft flies at a lower angle of attack and drag is reduced,” adds Gayton.

“An ideal aft center of gravity means that on the whole the aircraft will benefit from increased stability and better take-off and landing performance.”
IATA’s best practice guidelines say that properly managing an aircraft’s center of gravity will yield savings in the order of 1-2% during line operation.

They highlight that flying with an ‘aft’ center of gravity can reduce fuel consumption by as much as 1.5%.

Team best practice

Finding that sweet spot is a complex task, demanding that multi-discipline teams work in synergy to manage load balancing and fuel burn reduction.

Those teams comprise ground staff for load planning and flight operations, as well as cockpit crew.

For each flight, optimizing safety and efficiency requires best practice approaches based on:

  • Meticulous planning to calculate and identify how efficiencies can be attained.
  • Knowledge and expertise to implement methodologies for optimization.
  • Technology and processes to assist in decision making and ensuring compliance with industry standards.

In the words of IATA’s Assistant Director for Engineering & Maintenance, Tom Fodor: “Even the easier improvements can require detailed changes to be made across a number of departments. It can be very hard to achieve the improvements but it is important work.

“It isn’t enough to achieve a one-off result. Airlines must have in place the technology and processes that sustain fuel efficiency improvements.”

NextGen tools

That technology must comprise ever more sophisticated weight and balance tools to reach the aircraft’s optimal balance, and to cope with the increasing efficiency and capability of aircraft and engines.

While cockpit crew can optimize in-flight auto trim mechanisms to dynamically balance the aircraft during the cruise phase of flight, cutting edge tactical and strategic tools as embodied in SITA’s Horizon Weight & Balance are becoming critical for load planning on the ground.

SITA’s O’Neill again: “New generation tools are now essential for creating awareness across ground and flight operations teams about the critical importance of fuel efficiency and reduced carbon emissions, and how they can greatly improve fuel savings.”  

In the complex task of safely defining and optimizing the operational parameters for each flight, those tools must give load planners easy access to a range of critical flight, payload and other related data.

Such is the case with Horizon Weight & Balance, currently in deployment with several airlines and ground handlers. As one of the first innovations to emerge from SITA’s Next Generation Passenger Management program, it seamlessly embraces:   

  • Aircraft and flight technical data, such as structural weight limits and operating limits including weather, length of runway and the height of any obstacles on the flight path.
  • Variable data on payload, such as fuel, passengers, crew, baggage, and any cargo or mail. This is needed to position the aircraft’s center of gravity within a clearly defined permissible range to ensure stability and maneuverable in flight.
  • The ability to allow for an aircraft’s weight and center of gravity to change with fuel consumption.
  • Close integration with check-in systems, allowing dynamic adjustment up to departure. This enables better forecasting and calculation of a specific flight’s weight and aircraft balance based on passenger numbers, which are usually the most variable components of a flight.

Clear visibility

Unless they have the right tools, as load planners load up an aircraft it’s difficult for them to visualize the impact of their decisions on cost in real-time.

“Getting the right data is one challenge, but it’s equally important that next generation tools give clear visibility of the costs and consequences of poor aircraft balance,”  according to Kevin Pryor, Joint Managing Director of Liberator, whose technology is integrated with Horizon (see ‘Cost Manager Application’).

Again, the principles are embodied in SITA’s next generation Horizon Weight & Balance technology, with the integration of a powerful Cost Manager Application (CMAP) tool, encompassing center of gravity and aft calculations (see ‘Load planning – the next generation’).  

Cost culture

Highly intuitive and simple graphical displays show the ideal trim zone or cost penalty associated with an aircraft’s current load planning status and the loading changes being made to calculate the ideal trim position for the aircraft.

“Displaying big green or red buttons with dollar signs on them to indicate potential fuel waste will certainly motivate planners to rethink loading decisions,” says Pryor.

“This will empower airlines and ground handlers, enabling their staff to optimize fuel usage by giving them the ability to more easily manage an aircraft payload distribution and center of gravity.”

“What’s more, it introduces best practice while motivating staff to become cost managers in their own right, helping to ensure less fuel burn and much less cost.”

Cost manager application

In the quest to optimize flight plans, the more efficiently a loaded aircraft flies the more efficiently it burns fuel, making big savings.


SITA’s next generation Horizon Weight & Balance system gives load planners state-of-the-art tools to fine tune the ideal trim to optimize fuel efficiency.


Integrated with the system is Liberator's Cost Manager Application - Center of Gravity tool, (CMAP-cg). Taking into account center of gravity and aft calculations, it’s based on accepted industry standards and principles in the field of weight and balance and operations.


Variables include elements such as aircraft type, nautical mileage of flight, weight distribution, fuel cost and more.



Vitally, it’s highly intuitive for load planners who can make trim adjustments in real time. It graphically expresses the gap between actual and ideal balance in US$ as a cost penalty.


Weight & Balance screens show load planners red or green buttons so they can immediately make crucial weight and balance decisions, changing a load plan or moving dead load to different hold locations, for instance.


Green button: load plan is currently in the ideal trim zone. Optimum center of gravity for best fuel burn.      

Red button: cost penalty in US$ if load is forward of the ideal trim zone. Load control agent can make changes to get to ideal trim.   


Strategic planning

More than that, CMAP can be used to analyze trends based on real-time monitoring so that cost penalties can be identified and then fixed and sustained as part of the Fuel Management Program.


Liberator’s Joint Managing Director, Kevin Pryor, cites the tool’s ability to encourage “innovation and cost management awareness from the front‐line of the business.


He adds: “It equips Load Control and Management Teams to develop a way of working based on knowing, seeing and continuously reaping the cost saving benefits of being more aft more often where possible.”


According to Pryor, the tool’s drag and drop functionality “will help shift to a culture of ‘more aft center of gravity, more often’ that will quickly become pervasive.”


“Partnering with Liberator to provide the integrated CMAP capability uniquely positions SITA to be the leading provider of aircraft load control systems in optimizing costs by minimizing fuel burn," says John Gayton, Product Manager for Horizon Weight & Balance, SITA.


About Liberator

Liberator Aviation Services is a Dublin-based developer of innovative web-based tools and services with a focus on cost reduction, operational efficiency and enhanced levels of safety and communications.


Liberator supports airlines and handling agents in their continuing efforts to manage costs while consistently adhering to standard operating procedures.

Load planning - The next generation

SITA is introducing new features to the Horizon Weight & Balance system to increase productivity, optimize resource allocation, and reduce operating costs for load planning.


Central Load Control (CLC) enables load planning of multiple flights and points of departure to be managed from a central or remote location. Ground handlers can use the capabilities to serve multiple airlines.


Auto Load Planning (ALP) provides automated loading instructions based on airline-defined business rules that reflect load operating practices and other factors including aircraft type and configuration.


"With the addition of Centralized Load Control, the integration of CMAP, and the planned roll out of an Automated Load Planning and Cargo/Freighter capability, Horizon Weight & Balance provides a full end to end automated solution for aircraft load control,” says John Gayton, Product Manager for Horizon Weight & Balance at SITA.

A burning issue – Load balancing

Incorrect loading can adversely affect the aircraft in many ways:

  • A higher take-off speed is needed, resulting in a longer take-off run.
  • Rate and angle of climb will are reduced.
  • The service ceiling is lowered (maximum usable altitude).
  • Cruising speed is reduced and cruising range shortened.
  • Maneuverability is compromised.
  • A longer landing roll is required because the landing speed will be higher.


Optimizing aircraft balance achieves:

  • Reduced fuel burn of anywhere up to 1%.
  • Improved safety through better take-off and landing performance.
  • Reduced environmental impact.
  • Decreased wear and tear on aircraft structure, resulting in extended asset longevity.
  • Safer control and maneuverability.
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