
Very 'close' Qantas jets came within 800m of each other - thisisastopsign
https://www.airlineratings.com/news/close-qantas-jets-came-within-800m/
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anderspitman
My first coding job was at an avionics subcontractor. One of the senior
engineers there told me once that TCAS (Traffic Collision Avoidance System,
equipped on all large planes) is theoretically capable of resolving up to 127
aircraft all converging on the same point. As long as all the pilots follow
the directions, there won't be any collisions. I have no idea if that's
actually true, and could definitely be remembering it wrong, but it always
seemed impressive.

~~~
redis_mlc
Well, TCAS works great in an ideal world.

When you mix civil and military planes, and ATC and pilots who are non-native
English speakers, and when your TCAS can be broken, then you get accidents
like the German or Brazil collisions.

In the military regime, you must follow orders. In the US civil aviation
world, the pilot in command is the final authority and can deviate from any
ATC order, with possible paperwork and/or consequences.

Although English is the official language for international flying, local ATC
and pilots use their local languages.

There was a scandal in Hawaii when one flight school targeting Japanese
students was issuing FAA licenses to pilots who couldn't understand English.

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anamexis
TCAS is not ATC though, no? Also I don't know if TCAS is localized, but it's
only two words if I'm not mistaken, "Climb!" or "Descend!"

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i_am_proteus
And if TCAS says "Climb!" and the ATC says "Descend," what do you do?

Think quickly! Several hundred souls are on the line.

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anamexis
Climb - TCAS always takes precedence. This was standardized after this
incident: [https://en.wikipedia.org/wiki/2001_Japan_Airlines_mid-
air_in...](https://en.wikipedia.org/wiki/2001_Japan_Airlines_mid-air_incident)

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s_Hogg
Having been in and out of Sydney a lot, I find this very easy to believe. The
airport is straining at the limit for capacity, so they have been quite
adventurous in getting planes in and out of there for some time. Particularly
with the curfew limiting the hours of operation.*

* Not saying the curfew is a bad thing

~~~
sokoloff
Tight curfews are a bad thing, I think. There's an airport just down the road
from me, Hanscom (KBED) with an 11P-7A curfew. The shenanigans you see at
10:55P with sometimes three simultaneous landings (two aircraft and one helo
to the ramp) are no good for safety.

I've been picking people in the morning and I've more than once seen multiple
airplanes circling the field jockeying to be the first one down final at
7:00:00 like it's a sailboat race. Now, would the neighbors rather hear
airplanes flying multiple low-level patterns at mid-power from 6:45 to 7:05,
or would they be better off if airplanes could come in and land directly
[typically at a lower power setting and with only one approach]?

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chrisseaton
> multiple airplanes circling the field jockeying to be the first one down
> final at 7:00:00 like it's a sailboat race

I don't think it's up to the aircraft who lands first. That's not how airports
work.

~~~
JshWright
Depends on the airport. There are plenty of uncontrolled fields out there
which definitely rely on inbound aircraft to sort themselves out.

~~~
sokoloff
Agree. By the numbers, there are about 500 airports in the US with control
towers (some are part-time). There are over 20,000 airports without control
towers in the US.

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DominikPeters
Aviation Herald report:
[http://avherald.com/h?article=4cb85fbe&opt=0](http://avherald.com/h?article=4cb85fbe&opt=0)

~~~
larkeith
This should really be the linked article, much more informative. The charts at
the bottom are particularly helpful for understanding the sequence of events
(and seeing the conflict between standard departure and go around routes).

It will be interesting to see the investigation for this, as a layman I don't
know if such conflicting routes are standard, and how ATC is supposed to
respond to such a situation (presumably not by leaving it to the pilot to
avoid, like in this case, however).

~~~
t0mas88
It's quite common, because a departure route and the missed approach are both
designed around the same terrain/obstacles and often use the same navigation
beacons.

The way to solve it is for ATC to provide alternative missed approach
instructions. So they would say something like "Quantas 123, go around, turn
left heading 250, climb 2000ft" knowing that the departing aircraft is going
to make a right turn.

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tus88
> The Airbus A330 involved in the August 5, 2019, incident was taking off on
> runway 34 Right as a Boeing 737-800 landing on the same runway was
> instructed by air traffic control to perform a go-around.

This makes no sense. The seem to be blaming the go around. But what really
seems to have happened is they allowed and aircraft on a runway a plane was
about to land on. Who authorized this and why? What if the plane didn't go
around? Would it just have wiped out the plane on the runway?

And it sounds as if the 330 was both taking off ans flying at the same time.

> The A330 first officer, who was pilot flying, then saw the 737 in close
> proximity and, in response, reduced the aircraft’s angle of bank to reduce
> the turn towards the 737.

I don't get it.

~~~
detaro
I don't think you should read any of that as "blaming the go-around", but as
stating facts.

> _And it sounds as if the 330 was both taking off ans flying at the same
> time._

Time passed between the two events.

From how I read it: A330 is ready for take-off, 737 is in landing approach.
Tower realizes this is too close, tells 737 to abort and _turn right_ to give
the A330 space. But the A330 will take off and _also turn right_ because
that's where it is supposed to go. And that happens: A330 takes off, goes into
a hard right turn, alarms go off because it gets too close to 737 which is
still low and in soft right turn, A330 pilot doesn't turn quite as hard to
leave more space.

What exactly the mistake was and how grave it is is for the safety boards to
figure out (shouldn't have let the 737 get as far as it did? should have
stopped the A330 from takeoff? Should have warned both sides they'd get close
to each other? It actually was acceptable in the end because the controller
had it in sight?)

~~~
tus88
I still don't really understand. Unless the 737 was about to crash land right
on top of the 330, it must have turned right well before the airport. If the
330 took off, it would have been a few kilometers beyond the airport before it
turned right itself. I just can't visualize this 800m thing. If the 737 was so
close it's go round intersected a plane that took off, this story really
should read "737 narrowly averts crash landing into an airbus that was
mistakenly let onto runway". Smells like a coverup to me.

~~~
JshWright
There are standard "missed approach" routes published for each runway.
Generally they involve flying more or less directly over the runway before
turning to circle around for another attempt.

The 737 flew that route. As they were doing that, the 330 was taking off and
turning in the same direction after takeoff (as they were directed), so they
both wound up near each other a few km beyond the runway as they were both
turning to the right.

~~~
tus88
Now I am just flabbergasted. How on earth could they let the 330 take off in
that case? And it still seems to me if the 737 didn't execute a missed
approach, there would have been a crash on the runway. That is just as big a
deal as the 800m flyby. This story should be a bigger deal than is being made
out.

~~~
mjg59
You don't get the throughput major airports require without vectoring planes
to land before other planes have taken off from the same runway. If the plane
taking off takes too long you tell the landing plane to go around. This
happens daily - I've had planes I'm a passenger on do it twice. It wouldn't
have been a big deal at all except for them both having been directed to turn
right in conflicting ways.

