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Comment by tus88 | Hacker News Reader

> 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.

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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?)

This is basically correct. There are two other contributing factors:

- The controller who was talking to the two aircraft was a trainee (and being supervised by a senior controller).

- The sequence happened after sunset, but before EENT, and the controller cleared the aircraft after judging the distance visually. Most things aviation-related, and in particular visually judging distance, become much harder after the sun sets.

Incident info: http://avherald.com/h?article=4cb85fbe

Departing flight: https://flightaware.com/live/flight/QFA459/history/20190805/...

Sunset table: https://www.timeanddate.com/sun/australia/sydney?month=8&yea...

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.

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.

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.

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.

This is entirely standard procedure.

In Europe (and ICAO standards) the controller will say to the second plane "number 1, traffic departing ahead" to let them know and then only say "cleared to land" after the other plane has left the runway.

In the US this is a bit different, they will say "cleared to land, traffic departing ahead" and are trained to cancel the landing clearance if the other plane isn't off the runway fast enough.

In both cases the second plane is made aware of the first, so they're ready (should always be) for a missed approach.

> And it still seems to me if the 737 didn't execute a missed approach, there would have been a crash on the runway.

When you're approaching an intersection controlled by a traffic light, do you feel the same anxiety? There are cars occupying the same bit of road that you're going to be occupying in a few moments, and if you don't stop at the light, there will be a crash. I'm guessing you don't give it a second thought (you may double check that traffic has stopped before proceeding, and pilots do the same thing when they're landing).

It is very, very common for one plane to be on approach for a runway while another one is taking off. If the plane taking off is delayed at all, the approaching plane is told to go-around (which is what happened here). Happens all the time.

I haven't read up on this incident, but I suspect the approaching plane wasn't given clearance to land yet, and would have gone around on their own if they hadn't gotten that clearance in time.

Well there are go rounds and there are missed approaches. It appears this was the latter. I can't see how a standard go round involves flying at low altitude directly above a plane that is about to take off or taking off. Obviously planes can approach runways from a distance while others are taking off, it seems here it didn't just approach, but came close to actually landing.

> Well there are go rounds and there are missed approaches.

Yes there are, and they both use the same procedure.

> Obviously planes can approach runways from a distance while others are taking off, it seems here it didn't just approach, but came close to actually landing.

It got to point where the controller had to give them final clearance to land, or tell them to go-around. Obviously that point is going to be reasonably close to the runway.

A plane on an instrument approach when told to go around is expected to follow the missed approach procedure. Which 9 out of 10 times includes flying over the runway.

Isn't missed approach procedure to fly runway heading, however not to actually overfly the runway (ie, offset of centerline)?

For a visual flight in a small plane that's the way to do it (and then technically runway track instead of heading)

For an instrument flight there is a defined missed approach route that usually includes specific altitudes and turns to get you to some holding position.

If you're lined up on the runway, flying "runway heading" will overfly the runway.

Here's the details for the runway in question: https://www.airservicesaustralia.com/aip/current/dap/SSYGL06...

One plane landing shortly after another departs is standard procedure, provided they have sufficient separation [0]. However, the separation in this case became too tight after the previous landing had vacated the runway, so ATC issued a go-around - but the missed approach procedure and standard departure route for that runway coincided, resulting in the close approach [1].

Note that not enough separation in this case (for the landing) is probably about a mile.

[0] http://tfmlearning.faa.gov/Publications/atpubs/ATC/atc0310.h...

[1] http://avherald.com/h?article=4cb85fbe&opt=0

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