The Pacific: General Aviation & Questions The place for students, instructors and charter guys in Oz, NZ and the rest of Oceania.

DHC Beaver down in Hawkesbury

Old 6th Jul 2020, 11:20
  #341 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
Bonanza.

But I’m confident that that’s coincidence. I’m confident that if you put a ‘proper‘ CO detector in any ‘generic’ aircraft that’s idling on the ground, there will be a wind speed and direction that results in lots of exhaust gas circulating back into the cabin, especially if the windows are open.
Lead Balloon is offline  
Old 6th Jul 2020, 11:52
  #342 (permalink)  
 
Join Date: May 2016
Location: Sunshine Coast
Posts: 172
Originally Posted by Lead Balloon View Post
Bonanza.

But I’m confident that that’s coincidence. I’m confident that if you put a ‘proper‘ CO detector in any ‘generic’ aircraft that’s idling on the ground, there will be a wind speed and direction that results in lots of exhaust gas circulating back into the cabin, especially if the windows are open.
Thanks for that. It would be an interesting exercise to check that across a variety of types. Hopefully there will be some further investigative work on the matter in the final report on NOO.
MickG0105 is offline  
Old 6th Jul 2020, 12:08
  #343 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
I wouldn’t expect ATSB to do further investigative work across a variety of types, and would not criticise ATSB for not doing so. The ‘normal’ exposure to CO from the ‘normal’ operation of ‘average’ GA aircraft is evidently not a safety issue.

However, cracked exhausts and other defects will create CO risks in any GA aircraft. The questions in the case of this tragedy include:

1. Why were the defects in the engine bay not detected during any of the required inspections?

2. Why don’t the mandatory equipment requirements for a ‘standard’ GA aircraft require a reliable CO detector (and engine monitor) rather than pointless crap (from a safety perspective) like ADSB?
Lead Balloon is offline  
Old 11th Jul 2020, 02:06
  #344 (permalink)  
 
Join Date: Jul 2003
Location: Yorkey's Knob
Posts: 112
Hopefully, final report will detail a more credible path of CO into cabin.

A few points apparent in Interim report:

- Coroner did not test for CO

- Post crash engine inspection did not flag CO leak issue.

- 2 years after crash, having drawn a blank on cause, ATSB tested for CO and found elevated levels in 3 of the 6 cabin occupants, zero in other 3.

- Subsequent engine examination identified cracked exhaust flange at cylinder as CO source. (Leak is into free air, that is propwash, slipstream and would be very much diluted.)

- CO path through fwd firewall into engine bay is not mentioned.

- Path from engine bay into cabin is said to be via missing bolts of magneto access panel. I am not familiar with Beaver, but typically we’re talking 3 x 3/16 bolt holes.

Question then is, is it possible for something nothing CO via broken path to cause elevated levels of CO in such a short, about 7 or 8 minutes, period of engine operation?
Wingnuts is offline  
Old 11th Jul 2020, 04:26
  #345 (permalink)  
 
Join Date: Apr 2005
Location: Melbourne
Posts: 2,677
- 2 years after crash, having drawn a blank on cause, ATSB tested for CO and found elevated levels in 3 of the 6 cabin occupants, zero in other 3.
Do you mean that they reviewed the autopsy reports?
Squawk7700 is offline  
Old 11th Jul 2020, 05:53
  #346 (permalink)  
 
Join Date: Sep 2015
Location: Australia
Posts: 366
Originally Posted by Squawk7700 View Post
Do you mean that they reviewed the autopsy reports?
No, it was a bit more than that.

“During the draft investigation report review process, the aviation medical specialist engaged by the ATSB recommended that carbon monoxide (CO) toxicology testing be undertaken on blood samples of the aircraft occupants that had been taken and suitably stored by the New South Wales State Coroner. This required testing at a specialised laboratory. With results pending, the ATSB draft report was submitted to Directly Involved Parties (DIPs) in December 2019 for comment.

The results of the testing were provided to the ATSB in March 2020, indicating that the pilot and two of the passengers had elevated levels of CO. The ATSB notes that post-mortem examinations established that the pilot and passengers received fatal injuries sustained as a result of the impact sequence.

Since receiving the toxicology results, the ATSB has:
  • consulted with New South Wales Health pathology to confirm the integrity of the samples given the preservation method, storage temperature and duration
  • consulted with NSW Health forensic toxicology to confirm the accuracy of testing given the technique used and sample preparation
  • received independent advice from a forensic pharmacologist, and engaged an experienced independent forensic pathologist to advise on the testing and effects of the CO levels found in the occupants
  • undertaken research on CO poisoning and detectors relating to aircraft operations.
From this, the ATSB considers the levels of CO detected were likely to have adversely affected the pilot’s ability to control the aircraft during the flight.“
Cloudee is offline  
Old 11th Jul 2020, 06:58
  #347 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
Originally Posted by Wingnuts View Post
Hopefully, final report will detail a more credible path of CO into cabin.

A few points apparent in Interim report:

- Coroner did not test for CO

- Post crash engine inspection did not flag CO leak issue.

- 2 years after crash, having drawn a blank on cause, ATSB tested for CO and found elevated levels in 3 of the 6 cabin occupants, zero in other 3.

- Subsequent engine examination identified cracked exhaust flange at cylinder as CO source. (Leak is into free air, that is propwash, slipstream and would be very much diluted.)

- CO path through fwd firewall into engine bay is not mentioned.

- Path from engine bay into cabin is said to be via missing bolts of magneto access panel. I am not familiar with Beaver, but typically we’re talking 3 x 3/16 bolt holes.

Question then is, is it possible for something nothing CO via broken path to cause elevated levels of CO in such a short, about 7 or 8 minutes, period of engine operation?
I thought the pilot had done numerous flights in the aircraft on the day of the accident? And that the effects of CO don't abate quickly?

Air flow through cowlings is sometimes counter-intuitive.
Lead Balloon is offline  
Old 11th Jul 2020, 07:56
  #348 (permalink)  
 
Join Date: Apr 2005
Location: Melbourne
Posts: 2,677
Presumably that was the second flight for the passengers.
Squawk7700 is offline  
Old 11th Jul 2020, 10:38
  #349 (permalink)  
 
Join Date: Jun 2001
Location: FNQ ... It's Permanent!
Posts: 3,542
Were the passengers inhaling exhaust fumes from passing boats whilst having lunch? Or from the pizza oven?
Just as plausible as the other theories going around!
Capt Fathom is offline  
Old 11th Jul 2020, 10:56
  #350 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
If (big "IF") the crack in the exhaust that ATSB says was there prior to the accident, was in fact there prior to the accident, the potential for CO respiration would seem as plausible as a passenger knocking the pilot out or Angel Flight-related pressure. But if (big "IF") a crack of that size was, in fact, in the exhaust prior to the accident, what maintenance inspections were done and certified by whom in the previous year or so?

As with the Essendon tragedy, it will probably be the legal action commenced by the NOK etc of the deceased that will be the only effective avenue for the discovery and exposure of the truth.
Lead Balloon is offline  
Old 12th Jul 2020, 06:28
  #351 (permalink)  
 
Join Date: Mar 2008
Location: Victoria
Age: 73
Posts: 75
" Were the passengers inhaling exhaust fumes from passing boats whilst having lunch? Or from the pizza oven?
Just as plausible as the other theories going around! "

In my new career teaching RPL, PPL, CPL and ATPL theory we do make students very aware of the dangers of Carbon Monoxide poisoning:
CO is very insidious and not easily detected -
"
The affinity between hemoglobin and carbon monoxide is approximately 230 times stronger than the affinity between hemoglobin and oxygen so hemoglobin binds to carbon monoxide in preference to oxygen."
If anyone is exposed to CO the most obvious telltale is that lips and fingernails turn bright red.
Smoking, fireplaces, badly maintained gas heaters and FW190s all produce large amounts of CO. (that's apparently why FW190 pilots always wear an oxygen mask)
I have a niece that works at 000 and every winter they process several calls for families suffering from the problem.

Even 100% oxygen for several hours does not always end well for victims. The best solution apparently is to place them in oxygen hyperbaric chambers for many hours.
These are becoming more common in Australia these days as high level athletes and their teams use them to speed recovery from injuries.
Flingwing47 is offline  
Old 12th Jul 2020, 07:02
  #352 (permalink)  
 
Join Date: Apr 2019
Location: Australia
Posts: 239
Originally Posted by Flingwing47 View Post
Smoking, fireplaces, badly maintained gas heaters and FW190s all produce large amounts of CO. (that's apparently why FW190 pilots always wear an oxygen mask)
And even modern fighters such as the F-22:
https://www.adn.com/bush-pilot/artic...gs/2011/07/22/
Stickshift3000 is offline  
Old 12th Jul 2020, 10:16
  #353 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
Good to see that investigators are still occasionally able to entertain the possibility that the pilot is not at fault.
Lead Balloon is offline  
Old 12th Jul 2020, 11:55
  #354 (permalink)  
 
Join Date: Mar 2008
Location: Victoria
Age: 73
Posts: 75
Originally Posted by Stickshift3000 View Post
And even modern fighters such as the F-22:
https://www.adn.com/bush-pilot/artic...gs/2011/07/22/
This video is a little long winded - guy in a Mooney who went to sleep and woke up in a field 2 hours later - info re his CO levels is around 32 min mark.
Interesting fact - CO has a half life of 5 hours and his was 13% 5 hours after the crash. Broken heat exchanger/exhaust was the culprit
Flingwing47 is offline  
Old 15th Jul 2020, 01:06
  #355 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
Be careful out there:

https://www.abc.net.au/radio/newsrad...arbon/12452576

https://www.abc.net.au/news/2019-07-...hower/11341744

https://www.abc.net.au/news/2018-10-...eaths/10334098

(On a less serious front, I note a 2008 Cessna 182T advertised in the latest edition of the Aviation Trader has “CO2 detection”. Hopefully it reads a constant 0.04% or thereabouts!)
Lead Balloon is offline  
Old 15th Jul 2020, 02:34
  #356 (permalink)  
 
Join Date: Apr 2019
Location: Australia
Posts: 239
Originally Posted by Lead Balloon View Post
(On a less serious front, I note a 2008 Cessna 182T advertised in the latest edition of the Aviation Trader has “CO2 detection”. Hopefully it reads a constant 0.04% or thereabouts!)
Maybe it's to check if the pilot is still breathing (out)?!
Stickshift3000 is offline  
Old 17th Jul 2020, 05:31
  #357 (permalink)  
 
Join Date: Jul 2003
Location: Yorkey's Knob
Posts: 112
Ok.

If pax were experiencing CO symptoms on arrival at Cottage Point, it certainly would have dampened their appetite (Bank card statement might show this) and been a topic of conversation. Symptoms of low/moderate CO are headache, dizziness and nausea.

While pax were having lunch, pilot flew 4 x 20 to 30 minutes flights between Rose Bay and the Point. If pilot was flying under the influence of CO, signs would have obvious and a concern to pax. There is no record of pax on these flights suffering any ill effects.

Pilot considered himself fit for flight.

From the above, I think we can reasonably assume CO was not an issue prior to takeoff of fatal flight.

Given the short duration of flight, CO quantity into cabin would need to be substantial to result in ‘elevated levels’ in blood. Elevated level is such that it ‘affected pilot’s ability to control the aircraft’. To put the amount into perspective, it is the equivalent of a car’s undiluted exhaust into the cabin. All 6 people would have similar CO levels, not just 3 of them. They would have become drowsy and then in quick time, unconscious. The pilot would have been subtly incapacitated and unable to put the aircraft into a sudden, steep dive. Similarly for the pax.

Further, the pax in the right front seat, besides feeling the desire to take pics, was able to orient camera normally. This is inconsistent for someone with elevated levels of CO.

So to back up a little:

- Coroner did not suspect or test for CO

- Initial post crash inspection of exhaust did not note any pre-existing defect

- Exhaust path into cabin has not been established

- CO detector showed nil indication.



Many questions.
Wingnuts is offline  
Old 17th Jul 2020, 10:33
  #358 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
Pilot considered himself fit for flight.
You obviously haven't watched the video about the guy who woke up in his crashed Mooney in a paddock in the dark.
The effects of CO are not linear and include impaired decision-making. Non-expert PAX wouldn't notice subtle behavioral telltales of a pilot's deteriorating competence.
- CO detector showed nil indication.
What kind of CO detector was it, and what was its 'use by' date? Again, if you watch the video, comments are made about the reliability of traditional 'card' type detectors, even assuming they haven't been glued to an instrument panel forever. Plenty of other data about the reliability of them.
From the above, I think we can reasonably assume CO was not an issue prior to takeoff of fatal flight.
Speak for yourself.

And I note I'm no fan of ATSB, given the frequency with which it produces works of fiction and unhelpful mush.

Last edited by Lead Balloon; 17th Jul 2020 at 11:08.
Lead Balloon is offline  
Old 17th Jul 2020, 19:09
  #359 (permalink)  
 
Join Date: Mar 2008
Location: Victoria
Age: 73
Posts: 75
More interesting facts:

https://blog.aopa.org/aopa/2014/10/2...silent-killer/
Flingwing47 is offline  
Old 17th Jul 2020, 22:44
  #360 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 3,161
Originally Posted by Flingwing47 View Post
From the link:
Chemical spot detectors: Stay away from those ubiquitous el-cheapo adhesive-backed cardboard chemical spot detectors that are commonly sold by pilot shops and mail-order outfits for under trade names like “Dead Stop,” “Heads Up” and “Quantum Eye.” They have a very short useful life (about 30 days), and are extremely vulnerable to contamination from aromatic cleaners, solvents and other chemicals routinely used in aircraft maintenance.

These things often remain stuck on the instrument panel for years, providing a dangerous false sense of security. What’s worse, there’s no warning that the detector is outdated or has been contaminated—in some ways, that’s worse than not having a detector at all.

Even when fresh, chemical spot detectors are incapable of detecting low levels of CO. They’ll start turning color at 100ppm, but so slowly and subtly that you’ll never notice it. For all practical purposes, you’ll get no warning until concentrations rise to the 200 to 400 ppm range, by which time you’re likely to be too impaired to notice the color change.
Lead Balloon is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.