Optimized Profile Descents OPDs

[KB4TEZ]

Found this on my LinkedIn feed from FL360aero.

Planes heading to Orlando, Kansas City, Omaha, Reno and six airports in South Florida can now slide down from cruising altitude to final approach saving millions of gallons of fuel and reducing greenhouse gases.

The new Optimized Profile Descents (OPDs) safely eliminate the need for the fuel-consuming stair-step procedure. Under traditional procedures, aircraft repeatedly level off and power up the engines.

This burns more fuel and requires air traffic controllers to issue instructions at each step. With optimized descents, aircraft descend from cruising altitude to the runway in a smooth, continuous path with the engines at near idle.

Then this document was part of the discussion, pretty interesting IMO

https://applications.icao.int/tools/ATMiKIT/story_content/external_files/102600063919931_en.pdf

[diskus]

This seems like quite a challenge for controllers. Would be interesting to hear from some

[Rick108]

Yeah, for sure!  It's a great idea, but I wonder how this will work in practice.  I can't imagine we will start hearing aircraft at altitude and hundreds of miles from their destination get a clearance like "Descend pilot's discretion to 2000', report initial approach fix inbound"     Yikes!

[tyketto]

First off, the document is over 10 years old, without any updates to it. What tells me this is not only the publish date of the document, but the arrivals they use as in the example section; the RIIVR arrival hasn't been used in 6-8 years.


Second, some.. actually, a lot of this is already in use in the US.

For example, prior to doing any continuous descent operations, the En Route/Center controller would issue a hard crossing restriction at a waypoint that is used for handing off the aircraft to the terminal/TRACON area, where the TRACON would have control on descent for that arrival:

En Route: cross GRAMM at and maintain FL180.
En Route: Contact SOCAL Approach, 124.9.
Terminal: Descend via the RIIVR TWO arrival. At RIIVR, cleared ILS Runway 25 Left Approach.

Now, En Route gives the descent:

En Route: Descend via the ANJLL FOUR Arrival.
En Route: Contact SOCAL Approach, 124.9.
Terminal: After CRCUS, Cleared ILS Runway 25 Left Approach.

The pilot already will get the descent optimized and continuous by not having to deal with the hard crossing restriction before entering the Terminal area. So most of this is already done in the US with arrivals already optimized for it. They have been for a while.

BL.

[diskus]

But wouldnt the typical arrival procedure contain multiple crossing restrictions? I cant imagine they would allow for a continuous descent profile in many cases?

[tyketto]

But wouldnt the typical arrival procedure contain multiple crossing restrictions? I cant imagine they would allow for a continuous descent profile in many cases?

They do. So when ATC gives "Descend via" for the arrival, that authorizes the pilot to descend via the full arrival, adhering to all crossing and speed restrictions as depicted on the chart. Any modification to that call will not only make the pilot comply with the modification, but would cancel the arrival altogether. ATC would have to give another "descend via" to have them continue the arrival.

BL.