SPREADING THE RNP GOSPEL

Hardly a month passes without the debut of required navigation performance (RNP) procedures somewhere around the world. The benefits have become so apparent to airlines and aviation authorities that global deployment has achieved self-sustaining momentum.

The latest new deployment is in Abu Dhabi, where Etihad Airways has conducted the first approach using the most precise form of RNP, known as RNP-AR. This allows aircraft to fly tracks that are shorter and more efficient than traditional approaches. With the help of Airbus subsidiary Quovadis, Abu Dhabi will soon have RNP flight paths throughout its terminal airspace.

RNP approaches are being installed in locations as diverse as Seattle, Stockholm and Brisbane, Australia, to streamline airspace design and reduce the environmental impact of aviation on urban areas. In many other places, it is greatly improving approaches in mountainous terrain.

But while notable progress is being made globally, it has not been smooth sailing for RNP in the world’s busiest airspace system. U.S. airlines have criticized the FAA for moving too slowly to introduce these procedures, and for focusing too much on approaches that yield few improvements.

A new contract awarded by the FAA to ITT Exelis and GE Aviation may help speed the process. For the first time, private contractors are being tasked with designing the «public» RNP approaches that can be used by multiple carriers.

Previously, third-party designers have only been allowed to create custom RNP procedures for use by individual airlines. Only the FAA was able to design public-use approaches.

ITT Exelis is the prime contractor on the RNP project, with approaches to be developed at five airports. The FAA says this effort will supplement its own work, which has so far produced 305 RNP procedures.

The volume of new RNP approaches is not the only issue, though. Southwest Airlines spent $90 million to prepare a large proportion of its fleet and pilots to fly RNP approaches. But the carrier has been frustrated not just by the pace of deployment, but also by the relatively low usage rate.

In the first 20 days after it began using RNP in January 2011, Southwest conducted 1,400 approaches with this procedure. However, the rate slowed to fewer than 400 a month. This is due partly to controllers not approving RNP approaches, and also pilots giving up on requesting them.

Despite this, the global proliferation—and acceptance—of RNP is undeniable. The main question in the U.S. and other countries is no longer why, but when.

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