Required Navigation Performance Saves Time and Energy

If you’ve ever enjoyed the convenience of air travel, you’ve likely suffered the inconvenience of a delayed takeoff or landing. In the complicated world of air traffic control, any number of forces can impose on your tight schedule. And with more passengers and flights expected each year, such delays will only increase.

In an effort to stay ahead of growth trends and alleviate congestion issues, GE Aviation is introducing next-generation flight path technology at airports around the world. It may not sound like the sexiest of advancements, but once in place, such upgrades will not only save money and improve safety, they will also make traveling a more convenient and environmentally friendly experience.

Game changing technology

Required Navigation Performance (RNP) flight paths are one example of this technology and it was put to use February 23rd at the Lima International Airport in Peru. The Lima paths were developed by GE Aviation’s Performance-based Navigation (PBN) Services business and are specifically designed to target airport congestion.

“We want to get the most optimal procedure that delivers the highest performance measured in terms of a number of parameters: minimized fuel burn, minimized noise impact, minimized emissions, minimized delays, and reduced flight time,” said Steve Fulton, GE Aviation Technical Fellow. “That’s our focus. That’s our passion. That’s our DNA.”

These procedures cost time and fuel—and once engaged there’s still no guarantee that an aircraft will land the first time since pilots must still have visual confirmation of the runway before they can land.

Conventional landing procedures at most airports dictate all incoming aircraft queue in a straight line and approach the runway using a combination of ground-based radio-navigation signals and controller assistance. This often forces aircraft to fly indirect and inefficient paths to avoid obstacles such as mountains, buildings, or severe weather, creating unnecessary environmental and economic waste.

These procedures cost time and fuel—and once engaged there’s still no guarantee that an aircraft will land the first time since pilots must still have visual confirmation of the runway before they can land. What’s more, if the weather is particularly volatile, planes must sometimes abort final landing procedures and repeat the entire process over again.

GE’s RNP technology reduces these bottlenecks, allowing air traffic controllers to define a series of highly efficient, predictable flight paths from several different directions, which merge in perfect harmony along the glide path to the runway. And because of this technology, the point at which the pilot must have visual confirmation is often lower, decreasing the number of diversions.

Unlike ground-based guidance systems, there’s no equipment acquisition and maintenance costs for the airport and/or air navigation provider. RNP uses satellite signals to provide the lateral guidance and barometric sensors on board the aircraft to provide the vertical guidance.

“The aircraft carries the navigation system with it,” says Fulton. “This allows a global capability to conduct a full range of terminal navigation operations without any ground infrastructure.”

Lima’s big break

For Lima, the installation of RNP could not come at a better time. Serving more than 10 million passengers annually, the Lima International Airport is quickly becoming one of the fastest growing transportation terminals in the Americas. Unfortunately, its location presents a number of challenges. Not only is the airport flanked on nearly all sides by densely populated neighborhoods, but it lies in the shadow of the Andes Mountains—a physical barrier that cuts maneuvering flexibility, limits traffic access, and forces all incoming flights to approach from the west during poor weather.

According to Iain Box, GE’s Technical Lead on the Lima Airspace Assessment project, redesigning the airspace will provide dramatic efficiency improvements for traffic, while also addressing community concerns such as noise and air quality from emissions.

“The flexibility of the RNP flight paths allows us to strategically place these paths over non-residential areas, light industrial zones, roads, greenways, etc.,” he said. “RNP paths free operators from flying constraining, ‘straight-in’ approaches.”

Savings in Lima alone are expected to be $1.5 million per year, not counting the increase in revenue from the ability to handle larger capacity.

RNP also allows Lima operators to utilize optimal profile descents (OPDs) “because [planes] are not having to occasionally level off to keep clear of obstacles,” Box explained. “In effect the aircraft flies a constant descent in flight idle, and therefore you don’t have the thrust increase with each level off.”

As for the Eastern airspace formerly off-limits due to the Andes, it can now be leveraged to reduce congestion. “We can snake our way over river valleys and areas of lower terrain to now increase the capacity of the airspace,” Box said.

Comprehensive savings

All of these revisions translate into less fuel and CO2 emissions. Savings in Lima alone are expected to be $1.5 million per year, not counting the increase in revenue from the ability to handle larger capacity. As an example, one RNP route from Cusco to Lima will cut, on average, 18.9 nautical miles and save 6.3 minutes, 450 lbs of fuel, and 1,420 lbs of CO2 per flight.

According to a recent GE study, if RNP procedures were deployed at 46 mid-sized airports around the United States the annual savings would equal nearly 13 million gallons of fuel, 275 million lbs of CO2, and $65.5M in economic benefit. What’s more, the system would save over two years of travellers’ time with more efficient landings and takeoffs.

“RNP has been identified as a core technology to the global upgrade of air traffic systems,” says Fulton.

With GE Aviation having installed more than 400 routes globally, and with many more planned, this can only mean good things for both the environment and a busy travel schedule.