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DHC Beaver down in Hawkesbury

Old 2nd Jul 2020, 04:31
  #321 (permalink)  
 
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Ah old 'NBM' is available, brings back fond memories -)
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Old 2nd Jul 2020, 04:52
  #322 (permalink)  
 
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So, now the report appears to be due by the end of the 3rd quarter 2020, and the status has retrogressed from external review to internal review. Sounds more serious than a power on stall and the deceased pilot attempting to make "the impossible turn".
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Old 3rd Jul 2020, 01:22
  #323 (permalink)  
 
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"ATSB reveals pilot of Sydney Seaplanes crash was likely incapacitated by carbon monoxide in the cabin of Beaver floatplane. Six people killed when plane crashed into Jerusalem Bay on Dec 31, 2017"
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Old 3rd Jul 2020, 01:36
  #324 (permalink)  
 
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https://www.abc.net.au/news/2020-07-...river/12419706
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Old 3rd Jul 2020, 02:15
  #325 (permalink)  
 
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https://www.atsb.gov.au/media/news-i...e-in-aircraft/

Appears on the ATSB site

And the updated report 3 July 2020:
https://www.atsb.gov.au/publications...r/ao-2017-118/

Last edited by 0ttoL; 3rd Jul 2020 at 02:17. Reason: Updated
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Old 3rd Jul 2020, 02:49
  #326 (permalink)  
 
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If that is so, must have been a massive inflow of carbon monoxide to lncapacitate the pilot in such a short time. from T/O to unfortunate splash down. Beaver has windows? What about the blood results? And for the passengers as well.
A overwhelming stench of exhaust fumes in the cabin would cause the pilot to quit the T/O ,surely.
1c or 2c worth?
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Old 3rd Jul 2020, 03:39
  #327 (permalink)  
 
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Initial reports that leaked out into the wild very early on, spoke of a video or photos of the pilot had been found where he was slumped over the controls.

The explanation at at the was the part about the passenger having inadvertently done this which seemed far fetched.
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Old 3rd Jul 2020, 04:21
  #328 (permalink)  
 
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Years ago I purchased a proper CO detector. I did that because my research showed that by the time those ubiquitous ‘dot’ cards stuck to the dashboard turn black, you’re likely already blacked/blacking out yourself. Further, many leaks start small - pinholes in exhaust systems that develop into cracks and other engine bay/firewall defects - and these create low CO levels in the cockpit that can nonetheless be detected by a proper CO detector before deleterious effects arise.


I was alarmed - literally - at the amount of CO that sometimes entered the aircraft during taxi, depending on wind direction and speed. And that was with windows open (in fact - that may have been the / one of the path/s of entry) and without smelling any strong exhaust smells. I’m talking levels at which protracted exposure would likely result in deleterious effects.

My eventual practise was to leave the detector switched off during taxi and take off, to avoid the distractions, and turn it on during the cruise. (The ‘off the shelf’ item did no have an on/off switch. I added that myself.) Fortunately it always read/s a big fat 0 in the cruise. I figured that the risk of a defect developing to ‘bad’ between a landing and the next taxi, take off and climb to cruise were lower than the risk arising from distractions from the alarm.

The combination of protracted exposure on the ground combined with ongoing exposure in the air due to aircraft defects? Not good. (My inexpert guess is that a pilot’s pulse rate and metabolism are running a bit faster in the initial phases of a flight than sightseeing passengers after a nice lunch...)

Modern and effective CO detectors are cheap insurance, folks.
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Old 3rd Jul 2020, 10:49
  #329 (permalink)  
 
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Who makes a good detector? 12 volt.
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Old 3rd Jul 2020, 11:02
  #330 (permalink)  
 
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Carbon Monoxide poisoning leading to a total incapacitation after only several minutes in the air?
Anything is possible I guess, but I’m certainly sceptical.
Interesting development in the absence of any other cause?
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Old 3rd Jul 2020, 14:14
  #331 (permalink)  
 
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Originally Posted by Capt Fathom View Post
Carbon Monoxide poisoning leading to a total incapacitation after only several minutes in the air?
Anything is possible I guess, but I’m certainly sceptical.
Interesting development in the absence of any other cause?
Perhaps he wasn't totally incapacitated but sufficiently affected to make a serious error of judgement, by turning into Jerusalem Bay?
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Old 3rd Jul 2020, 22:07
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I haven't read the report to see how many sectors the pilot had flown that day. CO binds extremely extremely well to haemoglobin preventing the transfer of oxygen. Once it's in your bloodstream it takes ages to wash out.
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Old 3rd Jul 2020, 22:39
  #333 (permalink)  
 
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Originally Posted by werbil View Post
I haven't read the report to see how many sectors the pilot had flown that day. CO binds extremely extremely well to haemoglobin preventing the transfer of oxygen. Once it's in your bloodstream it takes ages to wash out.
According to the interim report, that day
... the pilot had conducted seven flights in VH-NOO. This included two short scenic flights over Sydney Harbour, four flights to/from Cottage Point, and one positioning flight without passengers from Cottage Point to Rose Bay. The accident flight was a return flight to Rose Bay.
The accident flight taxied away from Cottage Point around 1505 and was airborne around 1512, so a 6-7 minute taxi.

The photograph of the engine exhaust collector-ring showed a pre‑accident crack that had been further propagated by the crash. There was sufficient discolouration around the crack to suggest that exhaust gases had been escaping for some time.

Interestingly the report says blood tests showed 'the pilot and two of the passengers had elevated levels of CO'. The pilot I could understand; the two passengers strikes me as odd. Forensically the first question you'd want resolved is were any of them smokers; given the details recounted about the pilot it's unlikely he was.

Other pilots must have been flying NOO. I'd be interested to hear if anyone was complaining about headaches. CO poisoning is not entirely innocuous - a dull but persistent headache is a very commonly experienced early symptom.

Last edited by MickG0105; 3rd Jul 2020 at 23:30. Reason: Correction to number of flights that day
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Old 3rd Jul 2020, 23:12
  #334 (permalink)  
 
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Originally Posted by Sunfish View Post
Who makes a good detector? 12 volt.
https://www.aviationconsumer.com/saf...-experts-best/
Ours has the Experts (an earlier model than the 2016 in that article). It would consistently beep during taxi at a very low concentration level so have been looking for something different.
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Old 4th Jul 2020, 12:44
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"Elevated CO" is a very open ended, uncommitted statement.

Surely they can determine if "elevated" was "excessive" to the point of incapacitation?
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Old 5th Jul 2020, 12:20
  #336 (permalink)  
 
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I imagine it would be incredible difficult to be exact about something like that actually.
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Old 5th Jul 2020, 22:17
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Ozbiggles, I imagine it wouldn’t be too hard to model it. You know the pilots flight and duty history. Half life is apparently 3-4 hours. >30% produces serious symptoms. I don’t know the uptake mechanism and numbers, but I’m sure the aeromedical types can model it, at least to decide if it’s a possible cause - in the sense of calculating how big the leak would have had to be. Are we talking pinholes or bigger cracks?
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Old 6th Jul 2020, 00:09
  #338 (permalink)  
 
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Originally Posted by Sunfish View Post
Ozbiggles, I imagine it wouldn’t be too hard to model it. You know the pilots flight and duty history. Half life is apparently 3-4 hours. >30% produces serious symptoms. I don’t know the uptake mechanism and numbers, but I’m sure the aeromedical types can model it, at least to decide if it’s a possible cause - in the sense of calculating how big the leak would have had to be. Are we talking pinholes or bigger cracks?
Like any model, you would need to assume such wide variances/tolerances for each of these inputs (and more) that you can only arrive at an imprecise conclusion. This is probably what has been done under the circumstances.
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Old 6th Jul 2020, 10:29
  #339 (permalink)  
 
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Should be no modeling required.

Dose is measurable post mortem. Evidence in hand.

Not like there was a post accident fire to affect samples.
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Old 6th Jul 2020, 10:58
  #340 (permalink)  
 
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Originally Posted by Lead Balloon View Post
Years ago I purchased a proper CO detector. I did that because my research showed that by the time those ubiquitous ‘dot’ cards stuck to the dashboard turn black, you’re likely already blacked/blacking out yourself. Further, many leaks start small - pinholes in exhaust systems that develop into cracks and other engine bay/firewall defects - and these create low CO levels in the cockpit that can nonetheless be detected by a proper CO detector before deleterious effects arise.


I was alarmed - literally - at the amount of CO that sometimes entered the aircraft during taxi, depending on wind direction and speed. And that was with windows open (in fact - that may have been the / one of the path/s of entry) and without smelling any strong exhaust smells. I’m talking levels at which protracted exposure would likely result in deleterious effects.

My eventual practise was to leave the detector switched off during taxi and take off, to avoid the distractions, and turn it on during the cruise. (The ‘off the shelf’ item did no have an on/off switch. I added that myself.) Fortunately it always read/s a big fat 0 in the cruise. I figured that the risk of a defect developing to ‘bad’ between a landing and the next taxi, take off and climb to cruise were lower than the risk arising from distractions from the alarm.

The combination of protracted exposure on the ground combined with ongoing exposure in the air due to aircraft defects? Not good. (My inexpert guess is that a pilot’s pulse rate and metabolism are running a bit faster in the initial phases of a flight than sightseeing passengers after a nice lunch...)

Modern and effective CO detectors are cheap insurance, folks.
Can I ask what aircraft type you were talking about there please?

It appears that one of the contributing factors to CO ingressing the cabin on the ground is the position of the engine exhaust relative to the ingress points, typically the windows. Typically the exhaust ports are forward of cockpit windows.

I'm struck by the exhaust configuration for the Wasp Junior on the Beaver. Many are fitted with an extension that takes the expelled gases well to the rear of the forward doors. From the photos of NOO I've seen it didn't appear to be fitted with that extension so the exhaust gases appear to be expelled on the lower starboard side pretty much adjacent to the firewall.

I was also struck by what appears to be the very well ventilated engine compartment on the Beaver. The CO poisoning was meant to have been caused by exhaust gases leaking from a crack in the collector ring and then ingressing the cabin through three open bolt holes in the firewall. I would have thought that ventilation of the engine compartment would have carried leaked gases out the opening at the rear of the cowl.

Perhaps someone with time on the DHC-2 could comment.
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