
Visualizing Airline Flight Characteristics Between SFO and JFK - minimaxir
https://minimaxir.com/2019/10/sfo-jfk-flights/
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minimaxir
Fun note I learned while working on this post: it's very tricky to build data
visualizations that work well in both Light and Dark Mode.

I had used the ColorBrewer diverging palettes for the rainbow box plot color
schemes, but they're too light and have low contrast when inverted.

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caseyf7
Interestingly, I was struck by the colors you used and instantly checked your
code to find the palette. Your use of scale_fill_hue is beyond anything I’ve
seen before. Where can I learn more?

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minimaxir
It's nothing too unusual outside what's stated in the docs:
[https://ggplot2.tidyverse.org/reference/scale_hue.html](https://ggplot2.tidyverse.org/reference/scale_hue.html)

This is the first time I've used the start and direction parameters, though.

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jisaacso
I use to fly BOS <> SFO frequently.

One contributing factor is that the jetstream is stronger in winter months
than summer months. Flights from BOS to SFO are up to 1 hour longer (heading
into the jetstream) and 1 hour shorter from SFO to BOS (strong tailwinds).

In winter months, some airline's direct flights have to occasionally land and
refuel mid-country[1]. I've experienced this first hand a couple times.

[1] [https://thepointsguy.com/2018/02/winds-forcing-virgin-
americ...](https://thepointsguy.com/2018/02/winds-forcing-virgin-america-
flights-diversions/)

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burlesona
> Unlike the SFO → SEA charts, both charts are relatively flat over the years.
> However, when looking at seasonality, SFO → JFK dips in the summer and
> spikes during winter, while JFK → SFO does the complete opposite: dips
> during the winter and spikes during the summer, which is similar to the SFO
> → SEA route. I don’t have any guesses what would cause that behavior.

This one seems easy:

SF “summer” is actually foggy winter, whereas the winter months are mostly
pretty mild. (Admittedly less so at SFO than in the city but it’s often still
foggy.)

Airports tend to experience delays in wintery (wind and low visibility)
conditions.

Thus the seasonal delay is from arriving at the airport experiencing “winter
conditions.”

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cbhl
SFO is even worse during the fog -- if there is insufficient visibility, they
have to close one of the two runways because they're too close to use both
using instruments.

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djcapelis
It’s actually a bit more wild than that! SFO is _always_ too close to land
both runways at once via IFR alone. The second tail plane is required to land
while maintaining separation _visually_ , which can’t be done in bad weather.
Also, since wakes are what they are, the _second_ plane has to be the heavier
one. Which is how you get extremely large planes landing at a major
international airport under requirements in part for VFR.

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mannykannot
The difference between eastbound and westbound speeds, and their inverse
correlation, is to be expected, given that winds aloft are predominantly from
the west. Just from eyeballing the speed charts, there seems to be about a
70mph difference on average, corresponding to average westerly winds of half
that.

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mlindner
The graphs talking about flight speed are pretty nonsensical. The distance is
fixed, and they already graphed time, so the only difference here that
wouldn't be measured on the previous graph is route differences (assuming
they're actually using flown distance and not just straight line distance).

The comment: "he metrics from JFK indicate there’s about a 20% drop in flight
speed potentially due to wind resistance, which makes sense. " Also shows a
lot of ignorance. Air speed doesn't change based on direction, but flying
opposite directions sitting in the jet stream definitely does.

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NotSammyHagar
184 million rows is a lot? That's like when Dr. Evil asks the government to
pay you "One Million Dollars". Do you know what's really impressive? One
trillion rows, in just a second. [https://www.memsql.com/blog/memsql-
processing-shatters-trill...](https://www.memsql.com/blog/memsql-processing-
shatters-trillion-rows-per-second-barrier/)

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reaperducer
I'd like to see a version of this with data going back to the 1990's.

My memory is that before 9/11 and the aviation industry meltdown that planes
used to burn more fuel to get from coast to coast quicker than they do now.
But I'd like to see some actual numbers to determine if I remember that
correctly.

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gok
Hm these numbers look very different from the FAA's:
[https://www.faa.gov/nextgen/snapshots/airportpairs/?location...](https://www.faa.gov/nextgen/snapshots/airportpairs/?locationId=14)

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minimaxir
The elapsed times in this post are totals and include taxi/runway idling; that
link just does shows airborne time.

Adding an extra 20-40 minutes to the FAA averages seems to fit.

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gok
But the second table shows gate-to-gate?

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minimaxir
Oops, missed that chart.

The JFK → SFO data viz seems to track close enough with the average in that
second chart (it's lower, likely due to less outlier skew). The SEA → SFO
metric is the reverse of the displayed data visualization so that's not
applicable.

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aripickar
This is really interesting, I wonder what caused the spike in the summer of
2017? I don't remember it being especially hot, any instance a strike, or
anything like that.

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mandevil
JFK runway construction : [https://thepointsguy.com/2017/03/jfk-runway-
construction-201...](https://thepointsguy.com/2017/03/jfk-runway-
construction-2017/)

