How Shortcuts Across the Skies Can Make Flights Greener: Q&A

(Bloomberg) — Getting from A to B faster is generally the goal of most travelers, particularly for those flying long-haul in economy. 
Now, under a trial that started last month in Asia, shaving precious minutes off hours-long trips is a reality, depending upon what route a pilot chooses to take across the skies.
Since early August, air crew on selected routes between Singapore, Jakarta and a handful of cities in Australia and New Zealand have had the flexibility to choose the most direct and efficient path to get there. It’s about saving time, but also fuel, hence limiting greenhouse gas emissions.
Deviating from the fixed network of invisible highways that etch planes’ trajectories around the world and instead allowing a unique flight path for each plane may seem dicey, but it’s not as dangerous as it sounds.
Here’s a look at how it works.
1. What is the trial?
Singapore, Australia, Indonesia and New Zealand have banded together to make better use of their airspace to trial quicker, more direct flight paths.
The three-month trial started Aug. 5 and will be reviewed in November with a possible view to expanding it to more cities and airlines.
The carriers involved are Singapore Airlines Ltd., Qantas Airways Ltd., Air New Zealand Ltd. and Garuda Indonesia and they’re able to take shortcuts on 38 routes using what’s called user-preferred routing (UPR).
Singapore Airlines has said that it’s using the trial on 15 routes, including to Sydney, Christchurch, Darwin and Perth. Garuda said it’s operating user-preferred routing on flights from Jakarta to Sydney and Melbourne.
Other destinations involved include Brisbane, Cairns and Adelaide.
2. What’s behind the trial?
In short, climate change. 
The aim is to help cut emissions per flight, and the thinking is that over time, fuel and carbon emissions savings will multiply.
The Civil Aviation Authority of Singapore, in a statement Aug. 15, said that airlines can potentially save up to 1,700 kilograms of fuel for a flight between Singapore and Melbourne and more than 1,960 tonnes of carbon emissions a year for that route over a year of daily flights.
With about 10 flights a day each way, or some 7,745 scheduled flights between the two cities this year, according to data from Cirium, the numbers should start to add up. 
But user-preferred routing isn’t a silver bullet, especially considering the volume of flights is also rising, particularly in Asia, home to some of the fastest-growing air travel markets. 
McKinsey & Co. has estimated some $5 trillion of capital investment may be needed to deliver on aviation’s goal of reaching carbon neutrality by 2050, almost all of it plowed into sustainable fuel production and renewable power generation.
Making flights 10 to 15 minutes shorter generally doesn’t factor.
3. Have these kinds of airspace trials happened before?
User-preferred routing has been trialled as far back as 2008 and in some places, like Australia, a vast continent that has its own say over its airspace, it’s already happening.
Internationally, the practice has been limited due to the complexity of coordinating routes across national boundaries. Airservices Australia says it gets tricky when airspace is managed by different air navigation operators.
In New Zealand, another place that’s relatively geographically isolated, around 65% of flights across its some 26 million square kilometers of airspace use shortcuts where possible.
4. How do pilots arrange shortcuts and what role do air traffic controllers play?
Pilots typically follow waypoints, or fixed points in the sky to help planes navigate safely. 
Under user-preferred routing, pilots and their operations teams manually plug the most efficient route as they see it into flight planning software, taking into account things like wind speed and direction, turbulence and other environmental and weather factors. The flight planning system then creates its own unique waypoints.
Airservices Australia however says that “pilots and controllers are encouraged not to amend routes without good reason as most user-preferred routes aren’t the shortest distance in track miles.” The aim is to spend “the shortest time in the air, therefore flying a straight line between departure and arrival points is often not the most efficient route.”
Airways, New Zealand’s air navigation service provider, says it’s then up to air traffic controllers to “facilitate” these shortcut routes taking into account what other flights are happening at the same time.
5. It sounds potentially dangerous. Is it safe?
Completely. Airlines and aviation regulators are in no doubt about the benefits and the operational safety behind user-preferred routing. 
All trips are signed off on by air traffic controllers, whose job is to help safely navigate and manage airspace. There’s absolutely no freewheeling by pilots across the sky mid-flight, unless guided and advised by air traffic control staff on the ground.
“We do not share multiple flight plans to air traffic control, we only share once after the final flight plan has been set,” Garuda President Irfan Setiaputra said in a statement.
6. How’s the trial in Asia going so far?
Airservices Australia says there’s been anecdotal evidence of “considerable savings” for airlines in terms of fuel and carbon emissions, although declined to elaborate. 
“Some flights have better results than others,” it said. “The variability in conditions means that every flight is different.”
Garuda said the trial has allowed the carrier to “utilize tail wind conditions to make flight operations faster as well as more fuel efficient.”
Other participating airlines declined to offer specific data while the trail is underway.
7. Are there plans for trials beyond Asia?
Europe has sought to do something similar for 20 years under the Single European Sky initiative.
Aviation bodies and airlines from the continent have long tried to reform the congested airspace and effectively integrate the skies above almost 30 countries.
Under the Single European Sky plan, the vision was to have achieved, by 2020, an improvement in safety performance by a factor of 10, a 10% reduction in the impact flights have on the environment, a reduction in the cost of air-traffic management services to airspace users by at least 50% and a three-fold increase in capacity where needed.
It hasn’t worked out that way, with countries opting to hang onto their national air navigation service providers, and therefore benefits, like making the continent’s airspace cheaper, yet to be realized.
In the US, user-preferred routing is also new, with United Airlines Holdings Inc. completing its first such flight only in mid-2020, over Russia. In May 2023, the Federal Aviation Administration activated 169 new, set routes along the US east coast that are more direct, saving passengers time, and airlines fuel.
–With assistance from Siddharth Philip.
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