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Interesting argument for a new runway....

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Interesting argument for a new runway....

Old 8th Feb 2016, 10:47
  #21 (permalink)  
 
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"The obvious solution is for another parallel runway like at Sydney airport...."

Please for the love of god no..... Just NO!!
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Old 8th Feb 2016, 10:51
  #22 (permalink)  
 
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There was no supervisor from what I read. There was someone doing COORD and someone training on ADC with an OJTI watching. Perfectly legitimate. The COORD position sounds like they had OCA at the time but they were not a supervisor.

I am not saying in that instance that the aircraft were assigned their own separation, it was just an example.

Having read the interim information and knowing the location of the tower it seems perfectly plausible to me that the tower could visual separate the aircraft at night with the go around off 34 passing behind the 27 go around. Without more timings or an actual radar paint that is speculation on my part but the OJTI and ATSB also thought it was not an issue.
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Old 8th Feb 2016, 10:59
  #23 (permalink)  
 
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Be interested to know how much time ATC trainees spend in the Tower Simulator (located in Melbourne) before live operations, anyone know?
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Old 8th Feb 2016, 11:38
  #24 (permalink)  
 
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donpizmeov,

Firstly, why don't you get yourself a more sensible "handle", your present one, if indeed you are a Captain, suggests to me that you are "one of those captains "

Secondly, you say F/O's should be kept away from the P.A. Would you care to tell me how they are supposed to learn the great wisdom that you obviously have ?
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Old 8th Feb 2016, 11:43
  #25 (permalink)  
 
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it seems perfectly plausible to me that the tower could visual separate the aircraft at night with the go around off 34 passing behind the 27 go around. Without more timings or an actual radar paint that is speculation
Surely with limited ability to adjust speed, whether one aircraft passes behind is set by the spacing on final, i.e. if they are at 3.5 and 4 nm the spacing will be near enough 0.5 mile behind. Maybe that is a masterpiece if planning and timing, or maybe it is just how the cards fell on the day.

The assumption at that stage is that you don't have both go around (once in 175 years). There may be very little time to do anything once they do go around. Do ATC really visually judge crossing aircraft that finely at night (or even during the day?)

The report also suggests that turning one aircraft (for wake turbulence avoidance) below minimum vector altitude was not the right thing to do, which implies there is little you can do by turning aircraft either. Not that a turn would make much difference for aircraft crossing at near enough 90 degrees.

If speed and direction are fixed, altitude is dictated by the parameters of the missed approach, exactly what tools do ATC have to adjust separation in this situation - visually or otherwise?

OJTI and ATSB also thought it was not an issue
Some may suggest that Airservices are trying to play it down, and ATSB are prepared to assist.
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Old 8th Feb 2016, 12:45
  #26 (permalink)  
 
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I suppose some may suggest that.

Agreed about the 0.5nm apart if you ignore the fact that the intersection is approximately 1.4nm from the threshold of 34 and 0.6nm from threshold of 27. So you gain about another 0.8nm. The one on final 27 goes around first so is accelerating and then the 34 guy is turned right slightly due wake turbulence to pass behind the other one. If he turned him left slightly he was going to have problems but he didn't.

From the information we have available there isn't anything to cover up. If you don't trust ATC to visually separate you then I guess you can ask for a 3nm radar standard at all times.
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Old 8th Feb 2016, 13:00
  #27 (permalink)  
 
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Thanks AWOL, I was going to mention the distance to the intersection.

Andrew, as for your question "Do ATC really visually judge crossing aircraft that finely at night (or even during the day?)" Yes.
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Old 8th Feb 2016, 22:32
  #28 (permalink)  
 
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Agreed about the 0.5nm apart if you ignore the fact that the intersection is approximately 1.4nm from the threshold of 34 and 0.6nm from threshold of 27. So you gain about another 0.8nm.
The aircraft on 34 was 0.5 miles closer, so you need to subtract 0.5 miles from 0.8 miles, not add. It puts the aircraft on 34 0.3 miles behind the aircraft on 27 (without allowing for rounding or wind).

But the important question is not so much exactly what happened in this incident.The important questions are:

Is LAHSO conducted in a way that always allows simultaneous go arounds from both runways at any point in the approach without compromising separation,

and

If not, should it be?
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Old 8th Feb 2016, 23:04
  #29 (permalink)  
 
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ADCs use various separation methods, vertical, lateral, wake, radar, visual and RWY separation standards (distance and time). They are able to rapidly swirch between standards as required. E.g. From radar to visual as radar distance reduces below the minimum required. All ADCs are trained in compromised separation techniques which include a double LAHSO go around.
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Old 9th Feb 2016, 02:20
  #30 (permalink)  
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A query from the sidelines:

Are dual LAHSO arrivals sequenced at all by approach so that they don't hit their respective thresholds at the same time and hence dual-go-around into each other?
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Old 9th Feb 2016, 03:01
  #31 (permalink)  
 
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No. Non LAHSO acft are sequenced.
Remember that two aircraft arriving at the thresholds simultaneously are a long way apart as the ML RWY 34 threshold is about 2500 metres from the intersection whereas the RWY 27 threshold is much closer. If both go around at the threshold, the acft for RWY 34 will very high over the intersection, RWY27 much lower. aircraft are given mutual traffic with the landing clearance so crews are aware of each other. The ADC is able to visually separate. If required, the 34 arrival may be turned right towards the 27 threshold, it will pass well behind the 27 arrival.
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Old 9th Feb 2016, 05:35
  #32 (permalink)  
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Thanks - just curious - probably would have been better asking if they were sequenced so that at go around from 34 would not be lined up with a go around from 27 (which happened later) but your points on altitude is obviously the key differential. Would the same be true at Adelaide?
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Old 9th Feb 2016, 05:56
  #33 (permalink)  
 
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I don't know about Adelaide. I only ever held an SMC endorsement there in 1976 and they weren't doing LAHSO then. After that it was Parafield, Alice, Essendon and Melbourne.
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Old 9th Feb 2016, 14:18
  #34 (permalink)  
 
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Fujii, if what you are saying is AsA policy/mindset, I am worried. Are you seriously suggesting that a mitigator for a simultaneous G/A is the different heights that the aircraft will cross at? Just as concerning is your suggestion that "if required the 34 aircraft could be turned towards the 27 threshold". In the short time available, I seriously doubt whether the controller could accurately predict which way/how much to turn. Do they have dogfight training?

What is the visual standard when two aircraft are basically on a collision course within a couple of miles of each other with no organised vertical separation? Turn one so it missed the other by 500m?

I'm all for LAHSO, but not like happened there.
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Old 9th Feb 2016, 14:53
  #35 (permalink)  
 
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What is the visual standard when two aircraft are basically on a collision course within a couple of miles of each other with no organised vertical separation? Turn one so it missed the other by 500m?
Yep. The visual standard is to maintain azimuth. That may require a turn, it may not. I'd be interested to see the final report particularly any feedback from either QF crew and whether they felt it was an issue.
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Old 9th Feb 2016, 21:21
  #36 (permalink)  
 
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Remember that two aircraft arriving at the thresholds simultaneously are a long way apart as the ML RWY 34 threshold is about 2500 metres from the intersection whereas the RWY 27 threshold is much closer. If both go around at the threshold, the acft for RWY 34 will very high over the intersection, RWY27 much lower.
But if the RWY 27 aircraft goes around half a mile before the threshold they will be very close. There is always a distance that will put them at the same altitude.

If both aircraft go around in the last 30 seconds of approach, ATC will be hard pressed to do anything. If they issue instructions to the first aircraft, they may not even find out the second aircraft has gone around until it is past the intersection due to frequency congestion. It is fairly likely that ATC and the second aircraft would step on each other's radio transmissions.

The visual standard is to maintain azimuth.
If I understand you correctly, azimuth works fine for aircraft following the same path. For aircraft on crossing paths it is useless.
  • Azimuth will always reduce to zero when one aircraft crosses the line between a second aircraft and the observer.
  • For an observer at the airport, aircraft on a collision course will have azimuth separation right up to the point of impact.
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Old 10th Feb 2016, 00:18
  #37 (permalink)  
 
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In the scenario as played out on the video I believe from ML TWR it would have been possible to keep azimuth throughout the incident. As the 27 go around went through the intersection (from which the video is shot) the RWY 34 aircraft would be to the ADC's front and right and the 27 aircraft would be to his left and moving behind to the left. Might it have looked close out the window? I wasn't there so couldn't say.

Is there a point where if both aircraft went around they could conceivably reach the intersection at the same time and same altitude. I suppose so. I have no doubt ATC would have a plan of action if that was looking like it was going to be the case. I'd like to think the aircrew would as well given they are all told about each other.
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Old 10th Feb 2016, 01:23
  #38 (permalink)  
 
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I'd like to think the aircrew would as well given they are all told about each other.
I doubt it. When I'm doing your own control OCTA and I am high alert for this, I'm ready for it (and there is no way I would allow that MEL scenario to develop out in the sticks). But I'm in a CTR under positive ATC control at less than 1500ft on final, considering how I might extricate myself if I do a simultaneous go around with an aeroplane I probably can't see is fairly low down on the priority list, especially at night.

In my view, ATC must build in decent lateral separation/stagger for these types of LAHSOs.
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Old 10th Feb 2016, 03:45
  #39 (permalink)  
 
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If staggered so they don't meet at the intersection, it isn't really LAHSO. I.e. there wouldn't be a reason to hold short.
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Old 11th Feb 2016, 11:57
  #40 (permalink)  
 
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http://www.buzzfeed.com/markdistefan...ss#.wnW8EKEzj6
At least Senator Heffernan can give us a laugh.
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