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Comment by godshatter | Hacker News Reader

Shouldn't the dispatcher have given more precise directions than "follow the river"? If they had said "take a right and follow the river", this wouldn't have been a problem. I suppose they were used to professional pilots knowing what was meant, but they were already working to fit a small plane into a larger system presumably filled with mostly larger jets from commercial airlines that flew in and out of that airport regularly. Although I do agree that the pilot should have had no-fly zones at the top of their mind when flying in or around D.C.

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Actually no. The fact that to the left was a restricted airspace (that the pilot must be aware of) disambiguates the instructions already. Obviously the pilot did not do their flight preparation, was it includes being familiar with any airspace restrictions.

Also. I'm looking at a chart of the DC airspace. P-56, the restricted airspace containing the White House, is not on any rivers. If you are following the river (left, right, doesn't matter) then you are not getting into P-56. If you are oscillating around the river then yeah, you are going to have a bad time.

Also, I'm looking at all the runways at this airport. They all have one obvious direction which way you should be following the river. Just from the angle your flightpath would be crossing the river.

If you take off northbound, you only have a few seconds to turn left with the river before you’re over DC and into restricted airspace. If you take off and obliviously fly straight, it’s too late. It’s not a wide river.

Once you’re across the river, turning left is way worse (takes you directly over the federal complex), so ATC told them to turn right to exit the restricted airspace. That would take them around over SE DC.

Yeah. No joke. it is even on the departure chart: "Departing Rwy 1 requires expeditious intercept of outbound course to ensure avoidance of P-56 boundary"

Taking off north-bound (runway 1) wouldn't give you the option of flying up the Anacostia (the right spur that bisects DC when looking at a standard map).

Taking of north-east (runway 4) would give you the option of taking the Potomac (left) or Anacostia (right).

I've never seen runway 4 used. It's usually a north flow using 1.

From the description they took off from 18 (now 19 due to pole drift) it sounds like they might have taken a left basically immediately off the runway which would put them pointed pretty directly at the restricted airspace around the Capital and White House. It is odd they'd be there though considering the story says the check for the river on reaching 1500 which even at best climb would be around two minutes after take off which should be well past the river.

Not a pilot so I don't know if they'd use that language today, but there have been more than a few lessons written in blood over the years regarding ambiguous/unclear ATC communications. For example the worst air disaster ever occurred in part because a controller gave the instruction (paraphrasing), "cleared to beacon after takeoff." It was intended only as instructions to be followed after takeoff, but the pilot interpreted it as, "you are cleared to takeoff, then follow these instructions." The airport was under heavy fog at the time so he couldn't see the plane that was taxiing and hadn't cleared the runway yet. Two 747s collided and nearly 600 people died.

Source: https://en.m.wikipedia.org/wiki/Tenerife_airport_disaster

Honestly, I'm surprised by "follow the river" as a flight instruction. That sounds like the directions you'd get from someone that doesn't understand cardinal directions. "Turn right at the gas station, then turn left at the big oak tree" or something.

I have no experience with flying, but I assumed it would be a heading / cardinal direction and not "turn right at [landmark]"

This is a fairly common instruction from a controller in my experience, at least when dealing with small aircraft that they know are flying VFR. Traditional VFR navigation ("pilotage") is mostly based on finding landmarks anyway. Flying in another city with a runway pointed towards a river, "turn after the river," "report crossing the river" are common instructions.

Other landmarks popular with controllers include the freeway, the big Marriot, the Amazon warehouse, etc. It's sort of surprisingly informal when controllers are dealing with local light aircraft pilots. But that's mostly how those pilots are navigating anyway, "follow the freeway until the bridge."

There probably is a certain risk of misunderstanding here, but then pilots are expected to be reasonably familiar with the local area and its procedures, and to ask for vectors when unsure. These days DC is one of those places that it's strongly recommended (required by FARs now, I think?) to take a familiarization course because the airspace issues there are so sensitive. Plus they have the laser gun to minimize the need to send fighters.

Indeed. Popular landmarks used by ATC in the SF Bay Area include a sunken ship in the middle of the bay, a (particularly large) church, a community college, an AT&T telephone office, the KNBR antenna, and major freeways. Among others.

It's different when flying IFR, but pilotage is an important part of VFR navigation.

It's also worth noting there's an IFR visual approach plate for DCA that basically says the same thing - "follow the river":

RIVER VISUAL RWY 19 - https://www.fly.faa.gov/Information/east/zdc/dca/atcCharts/D...

Don't forget Embassy Suites! Ha.

"follow the river" is more than a single turn; the river winds so it's a sequence of turns. Because of this saying follow the river is much more concise than the specific turns.

Many of the takeoff and landing patterns do follow the river: https://skyvector.com/airport/DCA/Ronald-Reagan-Washington-N...

It's actually fairly common (in my area, for example, it's common for the controller to tell you to follow the interstate for awhile, and it works especially well at night).

Keep in mind too that just telling someone to fly a certain direction is insufficient - the controller is trying to maintain separation among aircraft, so they need you to follow a particular path through a volume.

It's fairly obvious when you look at the map:

https://www.google.com/maps/place/Ronald+Reagan+Washington+N...

Left is upstream and away from DC. Right is towards restricted airspace.

Hmm, can someone just paint me that path into Google Maps?

Washington National has no 18, but only a 19, and I guess everyone takes off southwards as directly north is the White House? Also the river is like parallel to the runway and then the natural extension of it, so "follow the river" there is super clear, no turn needed?

I must be looking at the wrong airport?

> Washington National has no 18, but only a 19

Depending on how long ago this happened that could be the same runway. There was an article that made the front page here in the last month or so about how the movement of the magnetic poles requires runway names to be adjusted periodically. This isn't that same article, I didn't feel like digging through my history, but it explains the same topic.

https://www.ncei.noaa.gov/news/airport-runway-names-shift-ma...

Agreed on the rest though, I just can't figure out a path that makes this story make sense.

Indeed but CGPGrey explains it in excruciating detail on YouTube. https://m.youtube.com/watch?v=qD6bPNZRRbQ

Thanks for all and that link, but yeah I was assuming 18==19 already and meant to understand runway numbers, maybe should have left out that detail.

Actual question still sticks: Takeoff on 18 southwards basically makes you follow the river immediately. Where did this guy encounter his left/right decision, to get back towards white house? he must have made almost a uturn then?

And even assuming the article is a bit inaccurate and he took of northwards (thanks for pointing out the patterns pilots have to fly if doing that @ others): I still cannot imagine how that plane flew and where it matches the description of: "When I reached 1500 feet I looked down. I was crossing the river. It went right and left."

???

I always find it funny how shortly after CGPGrey posts about a thing (or John Oliver does a segment on LWT), a large number of commenters will speak on it as experts at the next available opportunity. It's obvious how many of us watch the same channels.

When planes take off northbound from National, they immediately bank left (northwest) to remain over the river and avoid the exclusion zones in DC.

Conversely, planes landing southbound follow the river and so are banking to the right until a few seconds before touching down.

You’re correct. I live near DC and travel there for photography (much like the novice pilot in the OP).

If you’re flying near DC, or anywhere really, you should at least have a broad understanding of where you cannot fly. That is your responsibility; nobody in your ear will say “remember, don’t go to the restricted airspace.”

The pilot never claims to be the victim here, either. They screwed up and learned their lesson.

I used to sit nearby on my lunch break, and on a clear day you could watch planes after takeoff clearly follow the course of the river N/NW until completely out of sight, which would probably have been close the DC/Maryland border. They would be going in and out every few minutes and they all took the exact same flight path.

Many planes take off northwards, and immediately bank to follow the river.

Famously, see:

https://en.wikipedia.org/wiki/Air_Florida_Flight_90

Nah it's pretty common. When I take people around the golden gate bridge ATC tells me "Remain west of the 101 / Keep the 101 off your right at or below 2,000". And then later "Remain north and west of bay bridge".

They probably assumed that a) the pilot knew about the exclusion zone (kind of a big deal!) and b) you follow a river downstream (usually) so their instruction seemed (to them) unambiguous.

> you follow a river downstream (usually)

Weird; I don't have that connotation of "follow" at all.

Taking off from runway 18 (now 19) you're pointed essentially down river already though. The Potomac is right there at the end of the runway. That's the most confusing part of the story to me is how he was ambiguously crossing the river after taking off basically straight downstream.

Yeah; this part makes no sense.

Anyone in possession of either a geographic sense of the area (or a VFR sectional) who has departed due south from National and is told to "maintain runway heading and follow the river" would not be confused.

It seems like the FAA guy had at least the core of the right idea that the author wasn't really prepared for flying out of such a busy airport and restricted area. Now afaik access is more restricted and flight plans from people who haven't taken a particular class on flying through Washington National will be denied, but you can still totally fly a small plane into and out of that airport if you really want to.

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