
Two Cathay Pacific captains lose eyesight during flights - turtlegrids
https://www.scmp.com/news/hong-kong/transport/article/3007392/two-cathay-pacific-captains-lose-eyesight-during-flights
======
crooked-v
Three factors to keep in mind:

Pilots, especially international pilots, sit for extremely long periods of
time, which is inherently bad for vascular health and makes it difficult to
get even the minimal exercise that even office workers get by walking around.

Shortness of breath and blurred vision are common symptoms of heart arrythmias
and other heart conditions.

Cathay Pacific is the world's largest cargo airline and the world's tenth
largest airline in terms of sales, so they employ a _lot_ of pilots.

~~~
duxup
It's also all of two guys, could happen to a small airline... still just two
guys. Hard to measure significance.

------
not_a_moth
Makes me think about fume events:

[http://avherald.com/h?article=4b6eb830&opt=1024](http://avherald.com/h?article=4b6eb830&opt=1024)

At a claimed 2,000 events per year, find it a little disturbing that there
aren't requirements to monitor air bleed.

~~~
crooked-v
I find that page kind of dubious at best, given the substantial number of
factual assertions without sources, the conveniently unavailable video, the
entirely anonymous letter cited as a source, and the basic fact that even the
very existence of "aerotoxic syndrome" has been rejected by inquiries and
studies in several countries[1][2].

[1]: [http://www.asma.org/asma/media/asma/Travel-
Publications/Cabi...](http://www.asma.org/asma/media/asma/Travel-
Publications/Cabin-Air-Quality-A-review-of-current-aviation-medical-
understanding-Jul13.pdf)

[2]:
[https://publications.parliament.uk/pa/ld199900/ldselect/ldsc...](https://publications.parliament.uk/pa/ld199900/ldselect/ldsctech/121/12107.htm)

Edit: The "evidence" on that page is the existence of pilots who died
prematurely of heart conditions and suicides, an anonymous letter scanned from
a self-published book, a conveniently unavailable video, a bunch of slides
without citations, the presumption that a lack of official information about a
supposed previous event (which has all the same hallmarks of non-proof) is
proof of a nefarious conspiracy, and a death report that mentions acute
myocardial infarction and lethal levels of opioids from which we're somehow
supposed to conclude that the actual cause of death was an airborne neurotoxin
inhaled 50 days before.

~~~
not_a_moth
Ok but "fume events" are reported all the time; I'm not sure what exactly
you're disputing. Maybe it sounds conspiracy-theory like to you, that there is
this not often discussed risk in flying due to supplying cabin air from the
jet engine directly, but the FAA has recently shown that their corporate
relations trump public safety, and there are clearly major financial interests
to downplay the risk and keep out of the mainstream. Folks should use their
own judgment.

~~~
crooked-v
The existence of fume events, and the basic health concerns that come with
being exposed to jet fumes or aerated oil, are not a conspiracy theory. The
idea that fume events are somehow linked to mass exposure to a neurotoxin that
the FAA _and every other major government_ are suppressing information about
is a conspiracy theory.

~~~
altfredd
> The idea that fume events are somehow linked to mass exposure to a
> neurotoxin that the FAA and every other major government are suppressing
> information about is a conspiracy theory.

Alternatively, there is no conspiracy, and _every major government_ simply
ignores dangers of aviation jet fumes. Sort of how everyone was sure, that
invisible radiation is near-harmless and that radium dials are safe to use,
until suddenly they weren't.

~~~
notahacker
Well yes, but when it's a safety obsessed industry that's conducted studies
into neurotoxins and cabin air is the subject of debates by national
Parliaments, there's also the possibility that the internet theorist with no
medical training might be being ignored because he's wrong. (the Mulder paper
is, admittedly, considerably more substantial, although it's also a study of a
single deceased individual)

------
i_am_proteus
The two incidents were about four weeks apart.

Would anyone here happen to have information on the base rate of commercial
airliners issuing a pan-pan due to one pilot becoming incapacitated?

~~~
FabHK
Don't know where to find numbers, but searching AvHerald could give you some
qualitative feel for it. Definitely happens quite a bit (no wonder, given how
many flights there are per day).

[http://avherald.com/h?search_term=incapacitated&opt=0&dosear...](http://avherald.com/h?search_term=incapacitated&opt=0&dosearch=1&search.x=0&search.y=0)

EDIT to add: fortunately, p^2 is quite small for small p. And apparently there
are rules in place to prevent both pilots having the fish for dinner.

[https://aviation.stackexchange.com/questions/555/is-it-
true-...](https://aviation.stackexchange.com/questions/555/is-it-true-that-
the-pilot-and-co-pilot-are-required-to-eat-different-meals)

[http://www.traveller.com.au/why-pilots-dont-eat-the-same-
mea...](http://www.traveller.com.au/why-pilots-dont-eat-the-same-meals-as-
passengers-or-other-pilots-h15uof)

EDIT 2: "More recently, a 2010 Civil Aviation Authority report suggested that
between 30 and 50 pilots, operating flights to or from a UK airport, are
incapacitated at the controls every year – many because of food poisoning."

(from the last link above)

~~~
i_am_proteus
Seems like it's frequently enough (and my assumption is that flights with
different crews are generally pretty independent, and largely independent of
airline) that "two incidents on one airline in one month" isn't a glaring-
alarm-raising-unlikely event.

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whatshisface
Are passengers at risk from the fumes that are causing pilots to pass out in
the cockpit and then die? Are these chemicals present in automotive oils?

~~~
crooked-v
The idea of "fumes that are causing pilots to pass out in the cockpit and then
die" (supposedly "aerotoxic syndrome") has been rejected by inquiries and
studies in several countries[1][2].

[1]: [http://www.asma.org/asma/media/asma/Travel-
Publications/Cabi...](http://www.asma.org/asma/media/asma/Travel-
Publications/Cabin-Air-Quality-A-review-of-current-aviation-medical-
understanding-Jul13.pdf)

[2]:
[https://publications.parliament.uk/pa/ld199900/ldselect/ldsc...](https://publications.parliament.uk/pa/ld199900/ldselect/ldsctech/121/12107.htm)

~~~
whatshisface
Apparently the studies were industry-funded. It would be nice to see an
independent study because the chemicals at hand are known to be neurotoxic and
they also have those symptoms.

~~~
crooked-v
Of the studies noted in my first link, two were funded by charitable
nonprofits, three were funded by government agencies, and none were funded by
the airline industry.

------
rconti
NB: A single flight would have a Captain and a First Officer. Therefore, this
is about two Captains on two _different_ flights.

Should have been obvious to me on headline reading, wasn't, alarm ensued.

------
sagebird
"A lower flight level to decrease the cabin pressure altitude was also
requested to assist with the captain’s recovery."

Doesn't flying lower make the cabin pressure increase?

~~~
AWildC182
Pressure _altitude_ , they describe cabin pressure in terms of apparent
altitude, usually 8000ft+/\- and by lowering the outside altitude they can
increase the internal pressure/decrease apparent altitude.

~~~
sagebird
I see what you are saying and the article's sentence is technically not wrong.
But it is a useless phrasing none the less. By decreasing altitude they
decrease apparent altitude... so what? How is that different than saying by
filling a glass with water I increase apparent fill level...

This is a medical situation so what is relevant is how the change effects the
body. So I think the most clear thing to say is that... they flew lower to
increase the cabin pressure. Maybe it is some thoughtless force of habit that
they chose to describe it that way.

~~~
mbrameld
Pressure altitude isn't the same as flight altitude. You can decrease flight
altitude dramatically without changing cabin pressure altitude. You can also
vary cabin pressure altitude without changing flight altitude. So saying they
descended to lower the cabin pressure altitude is not useless. It describes
the outcome (lower cabin pressure altitude) and how they achieved it (by
descending). There are other ways of changing cabin pressure altitude, and
there are reasons to descend other than for the purpose of lowering cabin
pressure altitude.

Edit: I see the "I don't understand this so it must be bad" reaction in a lot
of junior devs. It's interesting to see it show up in other areas!

~~~
sagebird
There is value in adding a concise, incorrect comment on hacker news if it is
presented in a clear and falsifiable way. I am sorry I did not google
"pressure altitude" before commenting and did not present my findings so
others could learn from it, but I am happy that AWildC182 cleared it up for
me.

I still think that the sentence in the article could be written in a clearer,
and more direct and correct manner -- that is I think it is bad for reasons
other than me not understanding the definition.

I understand that pressure altitude is a way to express pressure using a
theoretical equivalent altitude, and that it is widely used in aviation
because it is convenient and tangible way to express pressure!

Though, I still think the goal was to increase pressure (measured in
Atmospheres) on the person undergoing a medical emergency. There would be
almost no point for a space pilot to descend from 70 to 65 miles altitude in
contrast to a terrestrial pilot descending from 8 miles to 3 miles. Even
though the difference is pressure altitudes is the same (5 miles delta), the
difference in Atmospheres is hugely different. (In the space case there is
almost no difference because there is almost no pressure!) That indicates that
the patient requires an increase is pressure (Atmospheres) So why not write
"They descended to increase cabin pressure". It's simpler, more direct, and
shorter.

It's offensive to couch a personal insult as an "interesting observation"
about junior devs' failings showing up in other areas. Your whole comment
seems to be made in bad faith and attempts frame me as a fool to be laughed
at. This is one of the reasons I sometimes hate participating in hacker news.
Even if I'm an idiot I don't think the snark is justified.

~~~
mbrameld
You initially expressed confusion about the difference between altitude and
pressure altitude with your question "Doesn't flying lower make the cabin
pressure increase?"

When AWildC182 pointed out your mistake you insisted that the sentence was
useless because it was confusing to you. The sentence seems useless to you
because you don't have the depth of knowledge to understand it, and instead of
putting forth the effort to understand you throw up your hands and declare it
a bad sentence.

That pattern happens all the time in software with junior developers. They
come in so sure of their abilities that anything they don't understand must be
wrong or bad or useless. Your exchange here was the first time I had seen it
happen outside of software development and I thought it was interesting, so I
commented on it. If you find it insulting to have that behavior pointed out to
you I would suggest avoiding the behavior.

------
pizza
TIL about the medical certificate system for pilots. I guess I figured there
must have been something in place, didn't realize it was a tiered system.

~~~
sokoloff
That article might lead a reader towards a wrong conclusion. A first-class
medical is required for all air carrier operations. (That they bothered to
report that both pilots had a "class 1" medical would be seen as odd to anyone
in aviation.)

In rough terms, second-class medicals are good for commercial but not air-
carrier operations, and third-class medicals (or now, BasicMed) for private
aviation.

------
starpilot
HN seems to be on an aviation accident kick. Interesting to see how long this
trend lasts. There haven't been more events on this impact, they've just been
surfacing to the front page more frequently following 737 MAX stores.

~~~
skellera
Probably because the 737 issues were software related. And the trend of
airline news is just up in general because of that whole ordeal. News outlets
make articles of things that are currently relevant.

It’ll probably slow down soon.

------
emilfihlman
Is there any possibility of an infrared laser attack?

~~~
HeyLaughingBoy
From where?

~~~
Piskvorrr
Indeed. Inverse square law would make that a) low-altitude event, or b) high-
power beam.

~~~
emilfihlman
No, not really. You can easily blind people far away with lasers.

~~~
Piskvorrr
That depends of "far away" \- good luck trying to aim at something at FL 350,
yet it's only some ten clicks away from you.

------
a3n
Two? They were probably caused by a conspiracy theory. I've heard there's a
lot of those going around the days.

