The thing I miss the most in my flying is listening to Channel 9 air traffic control on United. There’s a certain familiarity to the discussions that’s just soothing.

The usual patter on approach of “descend maintain one two thousand” is going to change though — and at some airports is already changing. (HT: Alan H.)

That’s because more airports are moving to bringing planes in on a steady path to the ground instead of descending, leveling off, and descending again.

Leveling off involves cranking up the engines, which burns fuel. A steady glide to the ground burns less. And it allows descent to begin later, where the new approach pattern has been implemented descents begin a couple miles closer to the airport.

Usually, planes approaching an airport drop altitude in steps, cranking up the engines to level out in between. That makes it easier for pilots to control descents and for air traffic controllers to keep track of everyone and manage spacing between planes. Crews check in with the ground at each interval, making sure they’re clear to drop a few thousand more feet. It’s a safe but inefficient way to get lots of planes on the ground.

Now, planes flying into George Bush Intercontinental and William P. Hobby airports in Houston will follow “optimized profile descents.” Instead of descending in stages, they will steadily drop, keeping the throttle near idle for nearly 100 miles. It’s like sliding down the bannister instead of using the stairs. Less throttle means less wasted fuel and less noise for airport neighbors. Reducing check-ins with ground control reduces opportunities for miscommunication.

Here’s a video showing changes in Houston.

These changes are coming to North Texas, Northern and Southern California, Atlanta, and Charlotte. Each project costs $5 million to $9 million.

On average changes may save about four gallons of fuel per flight, which adds up to millions of dollars a year.

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