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PA46 Malibu N264DB missing in the English Channel

So a bit of engine or rather turbo power is simply wasted?

Indeed

EGTF, LFTF

dublinpilot wrote:

For example, if he was alive after the crash, and re-breathing air in a pocket of trapped air in the cabin, would this result in a similar reading?

No. CO2 is buy product of breathing while CO can be only produced by burning carbon compounds under certain conditions.

LDZA LDVA, Croatia

dublinpilot wrote:

For example, if he was alive after the crash, and re-breathing air in a pocket of trapped air in the cabin, would this result in a similar reading?

I believe that if that happened then the hypoxia / poisoning would be carbon dioxide rather than carbon monoxide?

The really relevant question (I believe) is what sort of CO concentration in the air being breathed by the subject (i.e. the cabin air) is necessary to give a COHb saturation level of 58%?

Last Edited by Graham at 15 Aug 10:53
EGLM & EGTN

dublinpilot wrote:

For example, if he was alive after the crash, and re-breathing air in a pocket of trapped air in the cabin, would this result in a similar reading?

No – animals don’t produce CO when oxidising stuff. If we did, we’d poison ourselves, as CO sticks to haemoglobin much better than oxygen does, and the CO wouldn’t even leave the lungs. We produce CO2.

CO is a particular problem because of how well it binds to haemoglobin. The only other possibility is that Sala boarded the plane already saturated with CO (for example, from having been in a room with a faulty boiler that’s flue gases are getting into the room – people have died in hotels from CO poisining in the past) but the levels of CO found in his body are very high, if this were the case he would likely have been very obviously suffering the effects of CO poisoning before even boarding the plane (although perhaps his levels of fitness are such that he could support more CO than a typical person – perhaps @MedEwok can weigh in on this).

Photos of the pilot show someone who certainly is not an athlete, so I guess if the CO was entering the plane’s cabin, it’s likely the pilot would have suffered more effects of CO poisoning than Sala.

Andreas IOM

I’m not sure fitness helps in this case (for example fit people tend to use their bottled o2 faster than regular folks), but given the levels and the cabin set up, the pilot would very obviously be affected in a very negative way.

EGTF, LFTF

denopa wrote:

for example fit people tend to use their bottled o2 faster than regular folks

Not a person trained in biology, but wouldn’t that be because muscle will tend to consume more energy than fat (or no muscle), anyway?

I could imagine that a high level of hemaoglobin in the blood could help a little bit (more cells that possibly take longer to saturate, but again lungs might also be able to ingest more (bad, in this case) air), but I’d imagine the effect to be mostly negligible.

By the time the pilot is completely incapacitated, the passenger wouldn’t probably be in good enough shape to notice or do anything about it (sadly, there isn’t really anything he would have been able to do)

alioth wrote:

the levels of CO found in his body are very high

Is it a reasonable guess guess that 58% saturation level is equivalent to FL 220 (only 42% of the oxygen carrying capability available)?

That would be roughly consistent with the quoted effects (dizzyness, confusion etc., and loss of consciousness being not far away)?

@MedEwok?

Graham wrote:

s what sort of CO concentration in the air being breathed by the subject (i.e. the cabin air) is necessary to give a COHb saturation level of 58%

Not much. Because it accumulates in the blood, 0.1% kills overnight, 0.2% in 1-2 hours, and 1% in minutes

Biggin Hill

Emir wrote:

No. CO2 is buy product of breathing while CO can be only produced by burning carbon compounds under certain conditions.

Indeed, engines that burn lean (excess oxygen) like a diesel, or LOP pertrol, produce less CO, and a rich petrol engine produces more, very rich to the point of being underpowered even more so (limited O2). This was one of the reasons diesels were pushed in the UK (rightly or wrongly)

denopa wrote:

I’m not sure fitness helps in this case

It is my limited understanding that the human body doesn’t have a way to measure our o2 saturation. It relies on CO2 saturation to control our breathing rate. i.e normally if we don’t have enough O2, CO2 will build up and we increase or breathing rate to exchange the two. With CO poisoning the body does not increase its O2 take up to compensate, because it has not detected an increase in CO2. An additional reason that CO is so insidious.

Last Edited by Ted at 15 Aug 14:21
Ted
United Kingdom

Carbon monoxide is poisonous primarily because it binds to substances within the mitochondria, rather than because it reduces the oxygen carrying capacity of the blood. Anybody with a CO level of 50% is probably going to die or suffer severe braindamage. I doubt they could have walked to the plane if their blood levels were that high at the outset.

Given that the plane flew to Nantes from the UK beforehand, it is pretty bad luck that the exhaust system heat exchanger failed during the subsequent flight, and failed with a big leak, not a little one.

Another possibility is that it had failed earlier but the previous flight was done pressurised.

And fairly obviously they didn’t spend 100 quid (or less) on a CO monitor which would have revealed the problem very loudly.

The CO explanation is doubly shocking given that the pilot was making radio calls until near the end, IIRC. It must have been a catastrophic failure in the exhaust system.

Another totally weird thing is: no autopilot!!!! Whatever use the plane was being put to (it for sure wasn’t paradropping), the AP was not working OR Ibbotson didn’t know how to use it. It makes it a “total muppet” operation. Who, in the 20th or 21st century, is going to be hand flying this kind of mission? Transporting VIP passengers, on last-minute ad-hoc flights, at night… Or any kind, in a PA46? Had the AP been used, the plane would have flown on in a straight line, until fuel exhaustion, and then it would have been obvious to the radar controller that the pilot was incapacitated. Both might have still died, but the pilot might have had a chance to notice he is feeling half dead and done something about it.

So many holes in the cheese lining up here:

  • flight illegal due to licensing (departing at night, but no night rating)
  • flight illegal due to licensing (departing into IMC, but no IR)
  • autopilot not working OR pilot being clueless (or both)
  • catastrophic failure of exhaust heat exchanger
  • no CO detector
  • operating the engine ROP (old fashioned but still common) so it makes CO

The first two have no direct bearing on the accident but

  • they would have influenced the flight planning and execution (to not draw attention unless absolutely unavoidable; assisted by no Mode S installed so the general usage of the plane could not be inferred from FR24 etc)
  • they would have delayed declaring an emergency (to not draw attention)
  • no instrument flying ability meant that a loss of control at night+IMC was much more likely if no AP available, regardless of the CO factor
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Shoreham EGKA, United Kingdom
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