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-   -   Mid - Air @ Caboolture (https://www.pprune.org/pacific-general-aviation-questions/653933-mid-air-caboolture.html)

Lead Balloon 1st Aug 2023 22:48

I wouldn’t use the word “assured” to describe separation in your first scenario, KR. The aircraft taking off might have to abort the take-off for some reason, the landing aircraft might have to do a go around for some reason …

CASR 91.370 is about when the aircraft taking-off commences the take-off run. It’s about the circumstances at that point in time, and I would hope that at that point in time we’re thinking about, or have already thought about, all of the things that could go wrong.

helispotter 2nd Aug 2023 01:42


Originally Posted by Dora-9 (Post 11477729)
...Thanks for posting the photos/diagrams, helispotter. I don't think your final diagram is quite right - note how the wreckage trail of VH-EDJ parallels 11/29. I'm sure when we eventually see the ATSB report, all will be revealed...

Yes, agreed. I was struggling with the location and apparent path of the wreckage compared to the reported take-off runway and runway intersection as another post also had. One or both pilots may have been taking collision avoidance action and aerodynamic forces after the collision would also influence path that -EDJ came down. The video footage referred to by ATSB likely makes it clear, but ATSB wrote -EDJ "had JUST taken off from runway 11" so doesn't sound like it had been in the air for long.

Squawk7700 2nd Aug 2023 02:24

Short of a strong headwind, in my aircraft which is exactly the same as EDJ, I’d probably be at around 250ft by the intersection and not overly manoeuvrable when in the initial climb phase… it would be hard to turn too steeply as it would in any other aircraft attempting to avoid traffic.

zzodr 3rd Aug 2023 01:55

It's likely at these runway angles from the pilot's view each aircraft was probably behind each others A-pillars at near constant bearing.
Similar to the Sea World helicopter crash.

nonsense 3rd Aug 2023 03:02


Originally Posted by zzodr (Post 11478412)
It's likely at these runway angles from the pilot's view each aircraft was probably behind each others A-pillars at near constant bearing.

As described in detail in this video about an intersection with a history of car=bicycle fatal crashes:


fineline 4th Aug 2023 00:54


Originally Posted by Squawk7700 (Post 11477838)
Short of a strong headwind, in my aircraft which is exactly the same as EDJ, I’d probably be at around 250ft by the intersection and not overly manoeuvrable when in the initial climb phase… it would be hard to turn too steeply as it would in any other aircraft attempting to avoid traffic.

That's if you even saw them. High wing vs low wing another factor here?

Traffic_Is_Er_Was 4th Aug 2023 12:58


Originally Posted by zzodr (Post 11478412)
It's likely at these runway angles from the pilot's view each aircraft was probably behind each others A-pillars at near constant bearing.
Similar to the Sea World helicopter crash.

If both aircraft were maintaining runway heading, the collision could only have occurred over the runway intersection as that is the only point their paths would intersect. If that did happen, it seems highly unlikely the Jab would have impacted where it did in the direction it did. One or both of them has obviously turned during their respective take off/go arounds, probably both to the left. My spit balling is the collision probably happened somewhere over the dam, hardstand or tree line in the area to the north of the intersection, where the tug would have come up on the Jab even more from the right rear quarter as they turned. Momentum and aerodynamics then could have put the Jab where it ended up. Looking down forward and left, I reckon the Pawnee would have a pretty big blind spot, and the Jab pilot would have to be looking back over his right shoulder.

43Inches 5th Aug 2023 00:20

I think this will just come down to an unfortunate set of circumstance where things were running too close to the wind to begin with. It all ended up with some additional factor that sealed the deal into an unlucky scenario where everything lined up the wrong way after too little margin was afforded. As said earlier, when doing these sort of things think not only if the maneuver itself is safe, but what happens if things don't go as planned, what's the safest out and so on. Remembering that both take-off and go-round situations are high workload and offer little chance of high energy turns to avoid things without bringing the safety of the aircraft into question. You also do not have enough time to 'arrange' a suitable de-conflict when things are so close, so you have to assume a lot about what the other players will do. Once you have a third party appear it will quickly draw your attention and then re-sighting the original conflict may be very difficult with background clutter.

A lot of things to think about, and, if thought about before the fact you will probably think it better to wait until everything is less complicated.

That being said, if you can come up with a way to stop these actions, prevent VFR into IMC, stop bravado acts close to the ground, well then move on and try to stop all the unnecessary accidents on the road. Your advice will be worth millions of dollars. But when most of these accidents come down to all participants thinking they had it all under control 'until', well there's not much you can do except educate on the dangers. Legislation, rules and such won't do anything to help. In reality you can not educate everyone on all possible situations in life, it takes some onus on the user to look beyond the minimal and take some responsibility for their actions.

Keith. 6th Aug 2023 00:01

No webcam in use ? If only for weather information, but no fixed device for daylight air/runway activities ?
All of this speculation could have been resolved by one wide angle camera.

KRviator 7th Aug 2023 01:27


Originally Posted by Keith. (Post 11480042)
No webcam in use ? If only for weather information, but no fixed device for daylight air/runway activities ?
All of this speculation could have been resolved by one wide angle camera.

Not really. I have a webcam on my hangar, and it's configured to upload one still image to Squawk 7700 's FTP server every 10 minutes. You're hinting at live streaming, which uses a lot of bandwidth for a once in a blue moon event. The other option for accident-investigation would be a 4K security camera or similar with a NVR on-site, but who'd pay for it? Universal ADS-B/EC devices with a receiver at each airport would be a better option as they'd provide benefits beyond the airport boundary.

Captn Rex Havack 7th Aug 2023 03:20

[QUOTE=KRviator;11477779]Given the Jab was well and truly airborne before the 06/24 intersection, is it a reasonable to think the pilot considered any runway beyond the intersection as "unusable" for the purposes of "thou shall not takeoff until crossing traffic is stopped/passed"... Even if the Pawnee hadn't stopped and had rolled through the intersection, the Jab was already airborne and, therefore, had assured separation vertically.

KR - not sure if I have your context wrong, but clearly vertical separation was not assured, and with the potential of the airborne aircraft going round, or the taking off aircraft aborting, speration can never be assured when two aircraft are converging to a crossing point like this. So don't do these pseudo LAHSO ops.

Squawk7700 7th Aug 2023 03:51

How it’s it done (can of worms?) at Melbourne’s Tullamarine as I understand that they do it in the big birds under specific conditions?

43Inches 7th Aug 2023 05:59

Actual video of the event might not be that useful anyway, there seems to be a lot of witnesses to the accident. Unless there's something particularly unusual that was not sighted, like some sort of drone or alien interference the video will just confirm what is already apparent. In some cases I'd rather not have video of an event involving people dying that is plastered all over the news and internet for however long for no other reason than viewership and no real help to authorities.

WRT to LAHSO at major airports, it is only done with the supervision of ATC. Something goes awry the tower can issue go-rounds, stop instructions and vectors to assist in avoidance. ATC is also another set of eyes for the unknown factors, like rogue taxiing aircraft possibly entering a runway. There is also possibly a stagger factor for arrivals, and definitely conservative factoring additional to normal landing distance requirements.

missy 7th Aug 2023 06:05


Originally Posted by Squawk7700 (Post 11480490)
How it’s it done (can of worms?) at Melbourne’s Tullamarine as I understand that they do it in the big birds under specific conditions?

Yes, that's a big can of worms and very much thread drift. It's not only Melbourne but other controlled aerodromes as well. Operated at Sydney, pre-parallel runway operations. Used to improve efficiency / reduce delays. Safe as houses, until it's not - suggest the following.

Near collision at Sydney (Kingsford Smith) Airport, HS-TMC and VH-HYC, 12 August 1991
SYDNEY 1991

Unsafe proximity and radar vector below minimum vector altitude involving a Boeing 777-31HER, A6-EBU, and two 737-838s, VH-VXS and VH-VYE, Melbourne Airport, Victoria, on 5 July 2015
MELBOURNE 2015

43Inches 7th Aug 2023 06:54

The Melbourne incident was not so much an issue with LAHSO, but more so trying to fit in a departure that was way too tight for an unpredictable international, combined with very late action to initiate the go-rounds. What was learned that night was that ATC had very little protocol for when things go wrong. The 777 should have been held earlier, the 27 arrival allowed to land, and the 34 arrival sent around.

KRviator 7th Aug 2023 09:18


KR - not sure if I have your context wrong, but clearly vertical separation was not assured, and with the potential of the airborne aircraft going round, or the taking off aircraft aborting, separation can never be assured when two aircraft are converging to a crossing point like this. So don't do these pseudo LAHSO ops.
No, you did get it right. And you're also right in that such a scenario doesn't consider the 'what if the Pawnee goes around' in terms of separation.

But then this very same scenario is repeated many times at Bankstown (and probably other Class D's) whereby they'll send helicopters across the runway at 500 with aircraft on final - such that if the landing aircraft does go around, you're now faced with an immediate separation issue. Like this one.... And that's with ATC - but of course, they also helpfully point out that "This incident serves as a reminder to keep a good lookout at all times, including in Class D airspace. Pilots are responsible for maintaining separation in Class D." putting the onus squarely back on us if we smack into a helicopter we never even saw or that was passed as traffic, while conducting a go-around...

sunnySA 7th Aug 2023 12:34


Originally Posted by KRviator (Post 11480582)
putting the onus squarely back on us if we smack into a helicopter we never even saw or that was passed as traffic, while conducting a go-around...

My bolding. Perhaps I've misread this. Could you please elaborate.

KRviator 8th Aug 2023 01:12


Originally Posted by sunnySA (Post 11480670)
My bolding. Perhaps I've misread this. Could you please elaborate.

From this ATSB report (with my additions in red):

As ZVO (The helicopter) crossed the airport boundary (with clearance to cross the runways midfield at 500AGL), the engineer (the passenger in the helicopter) sighted the aeroplane (MJT - The Cherokee) and alerted the pilot. The pilot then saw MJT in the go-around, at the same height as ZVO, and immediately conducted a left turn to increase separation between the helicopter and the aeroplane. MJT was about midfield (half way along the runway) when the instructor sighted the helicopter (ZVO) taking avoiding action.At about 1441, the controller advised the pilot of ZVO of MJT as relevant traffic (But not the Cherokee of the helicopter), and watched as the helicopter turned through 360° and passed MJT.

At that time, the instructor of MJT reported that they broadcast, stating that they were going around. On the recorded audio from the ADC frequency, about 8 seconds after the ADC advised ZVO of MJT, the instructor of MJT can be heard to start to broadcast, but was then over-transmitted by another radio broadcast.

The instructor of MJT estimated that the helicopter was within about 30–50 m horizontally and at the same height as MJT. The pilot of ZVO estimated the aeroplane was about 200 m away, and the ADC estimated the proximity to be about 120 m.

(And from a bit further on in the report)
Instructor of VH-MJT

The instructor of MJT commented that they were not aware of ZVO before sighting it after the pilot of ZVO had taken avoiding action and the ADC had issued the traffic alert.
Pilot of VH-VZO
They were not aware of the other aircraft at all before they saw it – they had not heard a call and were not aware of any aircraft in the training circuit. They did not know to look there for other aircraft traffic.
Controller comments
The aerodrome controller reported that they were monitoring an outbound helicopter on the TSAD when MJT commenced the go-around. As soon as they sighted the potential conflict, VZO had commenced a left turn and the ADC gave MJT as traffic to VZO. An off-duty controller, who was in the ATC tower at the time of the incident, commented that in Class D airspace, pilots have responsibility to see and avoid VFR aircraft and ATC has a responsibility to provide relevant traffic information to assist them to do that.
Easy to see how, in the absence of notification of crossing helicopter traffic as part of the landing clearance, you're relying on pure luck to miss them if you do go around. Lucky that ZVO's passenger saw the Cherokee. Lucky that they were flying something that allowed visibility over the nose in the climb. Lucky they went around when they did, and not 2 seconds later... When I go around in the RV, particularly without a passenger, my pitch attitude is 15-20* nose up depending on atmospherics with the RoC in the vicinity of 1500-1800FPM and I'm completely blind under the nose when climbing at Vy. I'd say there's several other aircraft where that might be the case too.

Relying on luck to miss another aircraft by 200m (best case) or 30m (worst case) when that was only due to the helicopter taking avoiding action after its' passenger - not the pilot - first saw the traffic going-around is not acceptable anywhere, yet alone in controlled airspace. But the ATSB and ATCO's still puts it back on us as pilots to avoid traffic we may not even know about.

43Inches 8th Aug 2023 02:49

https://www.atsb.gov.au/publications...ir/ao-2019-066

Controlled airspace is just as dangerous as OCTA if traffic information is not handled/understood and complied with. In this instance the only thing that saved a mid air collision (or at least a very close miss) between the ATR and PA-28 was TCAS, and even then it was only a TA, as the RA was inhibited at that altitude. Considering the position the PA28 was in below the ATR, it's unlikely the crew would have sighted them without the TA occurring. The Tower did not even see the conflict and was only alerted after the fact as they were dealing with a third aircraft.

There have been a number of actual collisions in CTA in the US in recent years.

https://live-production.wcms.abc-cdn...862&height=575
https://s30121.pcdn.co/wp-content/up...enial.jpg.webp

This the result of one of them where both crews were lucky to survive.

Squawk7700 8th Aug 2023 05:58

I laugh when people hint that they are safe flying in CTA at Moorabbin. The only thing controlled there, is chaos!


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