Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Someone wiser please correct me if I’m wrong, but I believe north flow means better safety and efficiency because you’re not using the river visual (manual flying) landing that direction. It makes sense that ATC would use it as the default absent weather constraints.

Not all flights from the north use a visual approach; when the weather sucks but they have to come in from that way, it's a GPS assisted landing with a slightly different plan.

And like a PP said, the air traffic is coordinated between all 3 airports in the area, so apparently south flow just works better for that coordination.

There are four southbound approach procedures. For those who are interested in details: the procedures are named “River Visual,” “RNP,” “LDA Y,” and “LDA Z.” If you google those terms you can find them on the FAA website. The good procedures are River Visual and RNP, which take planes over the river. River Visual requires the pilot to navigate visually, so it can only be used when visibility is at least 3 miles and cloud ceiling is at least 3500 feet. It can be used at night. RNP is an instrument approach but it requires advanced navigation, the FAA says that only 30% of the planes using DCA are capable of doing that approach.

The bad approach, LDA Y, has pilots fly straight in from outside the beltway on a compass bearing of 147 degrees directly to the airport. When they get to a point on the banks of the Potomac directly opposite GDS (38.903017 N, 77.086772, W) they can either continue straight or jog left to line up their approach. They have to maintain 3,000 feet to that point.

The terrible approach is LDA Z. They fly in on a compass bearing of 145 degrees to a point above Arizona Avenue and Sherier Place. They have to maintain 1700 feet to that point. Then they head to a point above the center of the Potomac by Georgetown (38.903519 N 77.075661 W), they have to maintain 1100 feet to that point. This is the flight path we’ve all come to know and hate. Note that the altitude is above sea level, when they fly more toward Loughborough they could be 900’ off the rooftops.

The LDA approaches have planes fly directly over residential neighborhoods at low altitudes. The FAA doesn't seem to care if planes deviate from the procedure or if they maintain minimum altitudes. The FAA claims that River Visual should be used unless atmospheric conditions allow, although planes often fly one of the LDA procedures when visibility is perfect, particularly late at night.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Someone wiser please correct me if I’m wrong, but I believe north flow means better safety and efficiency because you’re not using the river visual (manual flying) landing that direction. It makes sense that ATC would use it as the default absent weather constraints.

Not all flights from the north use a visual approach; when the weather sucks but they have to come in from that way, it's a GPS assisted landing with a slightly different plan.

And like a PP said, the air traffic is coordinated between all 3 airports in the area, so apparently south flow just works better for that coordination.

There are four southbound approach procedures. For those who are interested in details: the procedures are named “River Visual,” “RNP,” “LDA Y,” and “LDA Z.” If you google those terms you can find them on the FAA website. The good procedures are River Visual and RNP, which take planes over the river. River Visual requires the pilot to navigate visually, so it can only be used when visibility is at least 3 miles and cloud ceiling is at least 3500 feet. It can be used at night. RNP is an instrument approach but it requires advanced navigation, the FAA says that only 30% of the planes using DCA are capable of doing that approach.

The bad approach, LDA Y, has pilots fly straight in from outside the beltway on a compass bearing of 147 degrees directly to the airport. When they get to a point on the banks of the Potomac directly opposite GDS (38.903017 N, 77.086772, W) they can either continue straight or jog left to line up their approach. They have to maintain 3,000 feet to that point.

The terrible approach is LDA Z. They fly in on a compass bearing of 145 degrees to a point above Arizona Avenue and Sherier Place. They have to maintain 1700 feet to that point. Then they head to a point above the center of the Potomac by Georgetown (38.903519 N 77.075661 W), they have to maintain 1100 feet to that point. This is the flight path we’ve all come to know and hate. Note that the altitude is above sea level, when they fly more toward Loughborough they could be 900’ off the rooftops.

The LDA approaches have planes fly directly over residential neighborhoods at low altitudes. The FAA doesn't seem to care if planes deviate from the procedure or if they maintain minimum altitudes. The FAA claims that River Visual should be used unless atmospheric conditions allow, although planes often fly one of the LDA procedures when visibility is perfect, particularly late at night.

This is fascinating - thanks for posting.

I'm the PP who lives just south of the airport and from our end noise is much louder when we have takeoffs vs. landings. Is the complaint on the north end about landings? Because from a noise management standpoint I would be thrilled for you guys to "solve" the loud approaches problem by just having the takeoffs all day long whenever weather permits.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Someone wiser please correct me if I’m wrong, but I believe north flow means better safety and efficiency because you’re not using the river visual (manual flying) landing that direction. It makes sense that ATC would use it as the default absent weather constraints.

Not all flights from the north use a visual approach; when the weather sucks but they have to come in from that way, it's a GPS assisted landing with a slightly different plan.

And like a PP said, the air traffic is coordinated between all 3 airports in the area, so apparently south flow just works better for that coordination.

There are four southbound approach procedures. For those who are interested in details: the procedures are named “River Visual,” “RNP,” “LDA Y,” and “LDA Z.” If you google those terms you can find them on the FAA website. The good procedures are River Visual and RNP, which take planes over the river. River Visual requires the pilot to navigate visually, so it can only be used when visibility is at least 3 miles and cloud ceiling is at least 3500 feet. It can be used at night. RNP is an instrument approach but it requires advanced navigation, the FAA says that only 30% of the planes using DCA are capable of doing that approach.

The bad approach, LDA Y, has pilots fly straight in from outside the beltway on a compass bearing of 147 degrees directly to the airport. When they get to a point on the banks of the Potomac directly opposite GDS (38.903017 N, 77.086772, W) they can either continue straight or jog left to line up their approach. They have to maintain 3,000 feet to that point.

The terrible approach is LDA Z. They fly in on a compass bearing of 145 degrees to a point above Arizona Avenue and Sherier Place. They have to maintain 1700 feet to that point. Then they head to a point above the center of the Potomac by Georgetown (38.903519 N 77.075661 W), they have to maintain 1100 feet to that point. This is the flight path we’ve all come to know and hate. Note that the altitude is above sea level, when they fly more toward Loughborough they could be 900’ off the rooftops.

The LDA approaches have planes fly directly over residential neighborhoods at low altitudes. The FAA doesn't seem to care if planes deviate from the procedure or if they maintain minimum altitudes. The FAA claims that River Visual should be used unless atmospheric conditions allow, although planes often fly one of the LDA procedures when visibility is perfect, particularly late at night.

Anonymous wrote:It's utterly absurd that a major airport be located in the middle of a city. It should've been closed decades ago.
What was the point of building Dulles? The whole reason was to get air traffic out away from the densely populated areas where noise or crashing planes are going to have less of an impact. Keeping Reagan open is beyond stupid. It's reckless.

Anonymous wrote:

Anonymous wrote:Someone wiser please correct me if I’m wrong, but I believe north flow means better safety and efficiency because you’re not using the river visual (manual flying) landing that direction. It makes sense that ATC would use it as the default absent weather constraints.

Not all flights from the north use a visual approach; when the weather sucks but they have to come in from that way, it's a GPS assisted landing with a slightly different plan.

And like a PP said, the air traffic is coordinated between all 3 airports in the area, so apparently south flow just works better for that coordination.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:Someone wiser please correct me if I’m wrong, but I believe north flow means better safety and efficiency because you’re not using the river visual (manual flying) landing that direction. It makes sense that ATC would use it as the default absent weather constraints.

Not all flights from the north use a visual approach; when the weather sucks but they have to come in from that way, it's a GPS assisted landing with a slightly different plan.

And like a PP said, the air traffic is coordinated between all 3 airports in the area, so apparently south flow just works better for that coordination.

I saw this earlier in the thread about ATC coordination and south flow, but it doesn’t seem to line up with the 60% north flow figure.

I live just south of the airport in the flight path and based on my kid’s 5:45am daily wake up I get the sense that the airport often defaults to south flow in the early hours.

Anonymous wrote:

Anonymous wrote:Someone wiser please correct me if I’m wrong, but I believe north flow means better safety and efficiency because you’re not using the river visual (manual flying) landing that direction. It makes sense that ATC would use it as the default absent weather constraints.

Not all flights from the north use a visual approach; when the weather sucks but they have to come in from that way, it's a GPS assisted landing with a slightly different plan.

And like a PP said, the air traffic is coordinated between all 3 airports in the area, so apparently south flow just works better for that coordination.

Anonymous wrote:Someone wiser please correct me if I’m wrong, but I believe north flow means better safety and efficiency because you’re not using the river visual (manual flying) landing that direction. It makes sense that ATC would use it as the default absent weather constraints.

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Roughly, what percentage of time are planes taking off out of DCA toward the north vs. the south?

Does this link work? See slide 14 for fairly current data on this (presented in May of this year). Shows about 60% North Flow. (this does vary a bit by time of year in my experience)

https://issuu.com/southflowalliance/docs/sfa_ppt_2/14

Thanks for sharing. 60%? Yikes.

Anonymous wrote:

Anonymous wrote:

Roughly, what percentage of time are planes taking off out of DCA toward the north vs. the south?

Does this link work? See slide 14 for fairly current data on this (presented in May of this year). Shows about 60% North Flow. (this does vary a bit by time of year in my experience)

https://issuu.com/southflowalliance/docs/sfa_ppt_2/14

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:

Anonymous wrote:We recently moved to Glover Park. Today, the airplane engines started up at 6am and haven't stopped all day. This is the first time we noticed it since moving here a few weeks ago. We were shopping on Wisconsin Ave this morning and it's pretty clear that the planes are flying directly inland, rather than going up the Potomac River. I can visibly see them cutting inland.

What the heck is going on? Is there some sort security issue that they've changed the flight path? Does it seem worse than usual?

The flight path changed after 911. They usually start at 5:45 and can go till 11pm or later. Maybe you have your windows open? They fligh over NW DC because there is no congressional representation....so nothing you can do.

There's one main runway. The planes have to go somewhere, and the direction changes based on wind. Many parts of VA deal with noise as well.

This topic is so tiresome. You want to live in a major urban area? There will be noise!

Departures can be either northbound or southbound. Unless the wind is 10mph or greater from the north they fly southbound. That's the only change due to the wind. The ATC for DCA, IAD and BWI is coordinated, they prefer to have all three flying southbound because it's easier to coordinate.

None of the nine approved northbound departure procedures for DCA vary depending on the wind.

It's very hard to get information out of the FAA, but my hunch is they fly over neighborhoods when they want to boost throughput.

Anonymous wrote:

Roughly, what percentage of time are planes taking off out of DCA toward the north vs. the south?