Boeing Forecasts Renewable Jet Fuel May Supply 1% of Global Commercial Aviation Fuel Need by 2015
Univ. of South Florida Researchers Link Subsurface Clouds of Degraded Oil to BP Well

Alaska Airlines Test Flight of RNP Approach Lowered Emissions By 35% Compared to Conventional Landing

West-side approach to Sea-Tac, showing typical flight path (blue) and RNP flight path (green). Source: Alaska Airlines. Click to enlarge.

Alaska Airlines demonstrated next-generation flight procedures this week during a test flight over Puget Sound that burned less fuel and reduced emissions by 35% compared to a conventional landing. The flight was part of Alaska Air Group’s “Greener Skies” project at Seattle-Tacoma International Airport (Sea-Tac) focused on using satellite-based guidance technology pioneered by Alaska Airlines to fly more efficient landing procedures that will reduce environmental impacts in the Puget Sound region.

The test flight used satellite guidance technology called Required Navigation Performance (RNP) to fly more direct, continuous descent approaches. Alaska Airlines estimates the new procedures at Sea-Tac will cut fuel consumption by 2.1 million gallons annually and reduce carbon emissions by 22,000 metric tons. They will also reduce overflight noise for an estimated 750,000 people living below the affected flight corridor.

Performance-Based Navigation
Performance-based Navigation (PBN) is the specification by aviation authorities of the capabilities and requirements necessary to operate in a given airspace, or the use of a given procedure, instead of specifying required technologies or specific avionics.
RNAV (Area Navigation) is achieved through a combined use of aircraft navigation accuracy, route separation and/or air traffic control intervention.
RNP is RNAV operations with on-board navigation containment, monitoring and alerting.
—FAA RNAV and RNP Group

The airline, in cooperation with the Port of Seattle, Boeing and other airlines serving Sea-Tac, is seeking Federal Aviation Administration (FAA) approval for the procedures, which could ultimately be used by all properly equipped carriers at Sea-Tac.

Testing for the project began last summer and, since then, Alaska Airlines has flown two other demonstration flights and submitted more than half of the proposed procedures for FAA review. Representatives from Alaska, Boeing, the FAA and the Port of Seattle participated in the most recent demonstration to observe the level of flight path precision and fuel consumption on eight landing approaches in a Boeing 737-700.

With a landing weight similar to a typical passenger flight, the shorter and more efficient approaches reduced carbon emissions and saved 400 pounds of fuel per approach.

Sea-Tac is the ideal location to pursue this cutting-edge project. Seattle has the highest percentage of advanced RNP-equipped planes in the nation, and—working with the FAA—Alaska Airlines, Boeing and the Port of Seattle are committed to making ‘Greener Skies' a reality as soon as possible. Ultimately this project could serve as a blueprint for next-generation aviation technology throughout the country.

—Ben Minicucci, Alaska’s chief operating officer

Typically, commercial aircraft follow a lengthy approach pattern and series of stair-step descents before landing. Using RNP technology and a continuous descent, also called an optimized profile descent (OPD), aircraft can descend from cruise altitude to an airport runway along a shorter, more direct flight path at low power.

Conventional approach.   Optimized Profile Descent. Click to enlarge.

Planning and testing of the procedures will continue through the remainder of the year and will be integrated into Alaska Airlines and sister carrier Horizon Air’s commercial operations at Sea-Tac pending FAA approval.

Alaska Airlines RNP display. Source: Alaska Airlines. Click to enlarge.

Alaska Airlines pioneered RNP precision flight-guidance technology during the mid-1990s to help its planes land at remote and geographically challenging airports in the state of Alaska. RNP provides computer-plotted landing paths by using a combination of onboard navigation technology and the global positioning system (GPS) satellite network. It improves safety and reliability in all weather, and reduces reliance on ground-based navigation aids. Alaska Airlines currently uses FAA-approved RNP procedures at 23 US airports.

Alaska Airlines is the only major US air carrier with a completely RNP-equipped fleet and fully trained crews. Alaska is also the first airline approved by the FAA to conduct its own RNP flight validation. Horizon Air’s fleet will be fully RNP-equipped by the end of 2011.

RNP and OPD are part of the Next Generation Air Transportation System, the FAA’s plan to modernize the National Airspace System through 2025. This initiative will increase airspace capacity and efficiency while improving safety and reducing environmental impacts through the replacement of legacy ground-based equipment with new satellite-based technology and aircraft navigation capabilities.

As part of the initial Alaska Airlines RNP operational approval team, Boeing began installing RNP guidance technology on its aircraft in 1994. Currently, all Boeing production airplanes are RNP-capable, and solutions are available to upgrade the in-service fleet.

Boeing RNP functionality includes flight crew interface through a flight management control display unit (CDU) and the airplane crew alerting system. Navigation, flight planning, and alerting algorithms are contained in the airplane flight management function.




New technologies allow new processes that can save time and money.

This is similar to GPS units replacing maps in the free market.

But can we allow such a capitalistic process in an industry partially controlled by a government agency?

What if this reduces manpower requirements?

And why should we allow the greedy airlines to save money?
- - It will just go to the rich, to buy gas hogs.

We should NOT allow this until we have 1500 pages of law to control it and bring the airlines under tighter government control.

Dave Oh

Nice. This new landing procedure, combined with the new generation of jetliners with ultra-efficient extra-high bypass, geared-turbofan engines and a biofuel mix will greatly reduce CO2 emissions.

I have also wondered why aircraft do not reduce cabin pressures to cruising levels right as soon as the doors are closed and the plane is taxiing on the runway for takeoff. This alone will reduce takeoff weight slightly (~230 kg on an A380's 1134 m³ hold volume, assuming 17 kPa pressure difference between sea level and 5000 ft altitude equivalent at cruise) on one hand and also increase passenger comfort on the other, as the pressure change can take place more gradually.


17 kPa of negative pressure would collapse the fuselage.

RNP is a great idea. The specific fuel consumption of turbine engines is much better at altitude than on the ground. "Stair step" (actually slopes separated by flat segments) descents often require spoilers to meet descent-rate targets, then the engines are spooled up again. The ideal profile would be to stay at altitude as long as possible, then cut to flight idle and descend in a glide until full landing flaps are deployed on short final.


This is nothing new and could (and has effectively been) done for the last 20+ years in many countries (in Africa?) where direct ILS ++ approaches are not available due to poor or non-existant maintenance and certification or very old ground based systems.

GPS assisted guidance for final approaches and landings can easily be done at most airports. That is the way 90+% of all landings are done in many airports Afirica. Traditional predetermined fixed VORTAC, VOR/DME, ILS approaches are relics from last century and will be used as alternative navigational aids as long as they are not mandated out.

Traditional ground based navigational-approach-landing aids cost $$$B to install and cost $$B/year to maintain and to regularly certify without any real reasons other than back-up method and forced all flights to stay airborne longer. GPS based systems where certified as early as 1982. Reluctance to change and over stressed safety and security requirements are involved. The resources that could be saved could pay for an upgraded/new GPS multi-satellite system + ground based augmentation to increase accuracy and availability. It will come but could take another 20+ years.


Actually ground based navigation systems "from the last century" should be kept operational as backups since GPS satellite outages are not uncommon.

I've experienced several outages during GPS approaches and had to revert to the "relics" to complete the landing. I thanked my lucky stars that these facilities were still up.


@ ToppaTom

Are you suggesting that we get rid of the FAA and let private industry take care of aircraft certification as well as other flight safety iisues on ideological grounds?

Some industries unfortunately need to be regulated. The government let US banks run unregulated recently and the taxpayer payed the piper.

Canadian banks which are more tightly regulated came through this crisis unscathed.

From my vantage point capitalists are more than eager to privatize profits and socialise losses ie stick it to the taxpayers for their incompetence.


Yeah, and when you're talking about hundreds of tons of metal hurtling about in the sky, those losses are people's lives.


I am not suggesting that we get rid of the FAA.
Not at all.
I am only concerned that update will take years, maybe decades.


All NavAids-Comm-Radars and Air Traffic Control units have been privatized in Canada for over 10 years now and no major degradation in services have been noted. The complete lot was sold to NavCan for a fair book value. NavCan operations are financed from an air traffic charge (air/miles x airplane capacity) plus a certain percentage of the landing fees. Transport Canada kept the regulation, licensing and accident investigation responsibilities. Major airports were also privatized and smaller ones were sold to local communities but are still receiving minor subsidies to cover part of the operation expenses.

With the exception of polar areas (for lack of satellites over-head), satellite based navigation are very safe for enroute, approach and precision landings. In most other places, seven to nine satellites are picked up by approaching aircraft. Ground based (very low cost) augmentation equipment increases the accuracy and reliability for final landings. With the complementary new GPS satellite network currently going up, the quality of navigation guidance and communication will be further enhanced. Those new Nav/Com satellites will be equivalent or superior to current ground based systems making them obsolete and no longer required.

Satellite based system can easily cover the whole globe while ground based systems have to be duplicated everywhere. Many countries (the majority) do not have the financial resources to install, update, maintain and keep those ground based systems certified.

Another important advantage of satellite based systems is the possibility to reduce air traffic control units by a factor of 20 or more. One control center per very large country (instead of 20 in USA) or eventually one per continent could do a better, safer, lower cost job. Most (control) accidents happen while aircraft are transferred from one center to another. Of course, for safety and security reasons, all those major centers would be duplicated and well protected, deep into a mountain if required.

A parallel would be Electrified Vehicles versus traditional old fashion ICE vehicles. By 2030+, who will want to buy or drive a dangerous gas guzzler?


Yes indeed the Canadian air traffic control system was privatized which has resulted in a steady fee increase. This despite the fact that prior to privatization they promised it would not be the case.

On my last trip to Halifax I ended up paying $35 USD. An outrageous amount in my opinion since the only services I used were tower communication and a weather briefing. Radar services were not required in this case since I was operating under Visual Flight Rules (VFR).

In the US these services are paid with a federal tax on aviation fuel. As a matter of fact thistax also funds the FAA not just air traffic control services. This has served the industry well. It is by far the least expensive world wide.

If one looks at the cost of flying for various western industrialized countries one finds that Europe as well as Australia are some of the most expensive locations. AOPA, the airplane owners and pilot association, has done some extensive surveys in the last few years on this issue. In Europe the fees can approach $1000 USD for some flights. Australia is somewhat less expensive than Europe but still not as cheap as the US.

As for control accidents, most occur at airports with a large percentage between aircraft that are on the ground. Runway incursion is a typical scenario. It is indeed rare that mid air collisions happen because a Center controller vectored an aircraft into the path of another. In fact I haven't heard of one in my 38 years of flying. Keep in mind that the air traffic control centers are responsible to provide traffic separation for enroute segment of the flight where traffic density is relatively low.



For decades, Canadian tax payers paid for most of the Navigation and Air Traffic Control and airport cost. Aircraft operators-owners used to pay less than 10% of the real Air Nav cost. Once privatized, users have to pay 100% of the real cost but tax payers save almost $5B/year. Small airports are still subsidized with tax payers money.

Direct users pay is fully justified in this case. The same does or should apply to roads and railroads. Gas taxes should be high enough to build and properly maintain all roads and bridges in good and safe conditions. Unfortunately, ground vehicles fuel taxes were used to support air traffic for many decades. Many national airlines unfairly still receive huge subsidies from their tax payers. That is unfair competition.


By the way, air traffic control also sequences approaches and landings where traffic density is much higher than on most enroute sectors. Future direct flights from A to Z together with curved GPS approach could reduce the average flight time by 5+%. This could be done without ground radars or ground Nav Aids once the new GPS/Com satellites are operational. Every aircraft will send its own position data as often as required for effective air traffic control. Adjacent aircraft will receive all data required to keep informed on traffic in the area.


Provided all aircraft are equipped with ADSB In and Out. Won't be mandated for another 10 years at the earliest.


The US Aviation Trust Fund which gets its revenue from aviation fuel taxes has been over funded for years.


...... Wont be mandated for another 10+ years..... That's one of the problem with updating/replacing traditional aviation grounds based systems. Satellite guidance is unofficially being used in more than 50% of the countries due to unreliable or failed ground systems and pilots have to make believe that they are VFR even in real IFR conditions. Less than 70 countries out of almost 200 have adequate certified ground systems in operation. Many commercial flights are paying for non-existant or non-operational ground NAvAids usage and flying (enroute + approach + landing) on GPS only. Those would have reasons to complain but they don't in order to keep going and not have to divert all cancel flights. Most commercial aircraft are already equipped with future ANS systems. Those few that are not could do it very quickly. Small general aviation planes and kytes are a manageable problem of another nature.

The comments to this entry are closed.