- An Optimized Profile Descent is a smooth way of landing planes with their engines close to idle.
- The landing style is less noisy, saves fuel, and reduces emissions.
In most cases, planes are pretty noisy when they land. The pilots slowly reduce the altitude of the plane step by step, throttling and decreasing as necessary, in what's called a "staircase descent.
The slow progression makes it easier for air traffic controllers to coordinate busy airspace and avoid collisions. But it's a source of both noise and carbon emissions, two things airports are trying to cut down as they work towards a net-zero aviation system by 2050.
That's why an increasing number of airports allow planes to "glide" down from cruising altitude with their engines close to idle. The new, smoother landing approach — "a gracious slide through the clouds," according to one flight reviewer — is called "Optimized Profile Descent" by the Federal Aviation Administration.
It's less noisy, saves fuel, reduces emissions, and is now allowed at 64 airports thanks to the addition of 11 new airports in 2022, including major hubs Orlando, Houston, and Miami.
With the new airports, the FAA estimates "the industry will save more than 90,000 gallons of fuel on average and will reduce greenhouse gas emissions by 27,000 tons annually."
"So it's a win, win, win and a win," John-Paul Clarke, an aerospace engineering and engineering mechanics professor at the University of Texas, Austin, who has studied continuous descents, told Scientific American. Clarke added that, while more fuel efficient, "gliding" is harder to implement, especially at busy airports, because of safety concerns.
The FAA started using optimized profile descents" in 2014. Their implementation is slow because it requires adjusting flight routes. You can't have dozens of idle planes smoothly glide into the same airport at the same time without some safety concerns.
The change in landing style is part of the US aviation's effort to achieve net-zero greenhouse gas emissions by 2050, as was outlined in the US Aviation Climate Action Plan released at a United Nations conference in 2021.
In 2021, the US recorded 4.9 billion metric tons of carbon dioxide emissions. US commercial aviation contributed to approximately 2% of the total. Other sustainability efforts include increasing the production of Sustainable Aviation Fuel — or SAF — a fuel that's similar to conventional jet fuel but can be up to 80% less carbon intensive.