lstorm2003

Hi, I have a question for the group... Last week I was flying a 182T from Zephyrhills, FL to Fort Lauderdale FL. As I approached Lake Okeechobee VFR at 5,500MSL from the NW I noticed a haze in the distance, that appeared to me to be smoke. I made this comment to my companion who is also a rated pilot. His opinion was that it was not smoke, it was just haze. I suggested we may want to deviate around it to which he replied, "no, look, its the same all around for 360 degrees...".

It did look hazy all around us but more so in the direction we were headed.. In any case within about 2 min the visibility went to zero and we were in solid IMC. Now as soon as we entered we immediately knew it was smoke from a ground fire, we could smell it. My concern at this point was for my own breathing, I did not want to become incapacitated due to lack of oxygen, but the smoke did not seem thick (although we could see nothing outside but opaque grey), and I was not having any trouble breathing.

We immediately made a turn to a heading that appeared to be more clear, and started a climb out of 5,500 to try to get on top of it. We broke out on top at about 8,000 and left the smoke behind us (and below) about 7 or 8 min after having entered it.

So now for my question... My question is could the engine have failed due to lack of oxygen when flying into this smoke cloud? I suppose its possible if the smoke were thick enough, but what would happen first, would I lose consciousness or would the engine quit?

And lastly if the engine had quit, would the visibility in a situation like this improve as I approached the ground? I assume it would, but am interested in other opinions on this situation I had...

IDIOTPILOT

I'm not an expert but my opinion is you would lose consciousness first. The smoke you are flying through is likely to contain carbon monoxide which would cause hypemic hypoxia. The carbon monoxide molecules bond to hemoglobin far better than oxygen. So even if there is sufficient oxygen to breath, the carbon monoxide would likely cause you to pass out. Engine failures have been noted around areas of volcanic ash. The theory is that a lack of oxygen can cause such failures and there has likely been some testing regarding this subject. However, for a simple ground fire in Florida, which seems typical, I don't see too much of a risk. Airtankers fly over fires all the time and I don't know of engine failures happening too often. Some airtankers are even single-engine and I doubt they would be used if an engine failure were that big a risk.

I'm not sure about the science on if you would pass out or engine fail first if the oxygen content was the same. But for practicality, I would say you'd probably pass out first.

rickair7777

You would become incapacitated from smoke inhalation before the engine quit, unless it was volcanic ash (extremely unlikely in FL!).

CO concentrations would probably not build up to fatal levels in the outdoors before the smoke or heat got you. It can reach unhealthy levels, but I'm not sure about incapacitation.

It's possible that thick enough smoke with large chunks could clog your air filter, but carb heat should take care of that.

Stryker

I spent a good amount of time flying in and around smoky air like that and I NEVER had as much as a sputter from a 172 or Seminole... I wouldnt recommend it as it will make your lungs hurt for a few weeks, but unless you are flying in a smoke plume for an extended period of time I highly doubt you would have a problem with the engine... But better to be safe than sorry...