UK AAIB (H) May 2020
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UK AAIB (H) May 2020
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"He also decided to open both the side vents and the nose vent as the carbon monoxide light had illuminated. This is not unusual when the helicopter engine is running for a period whilst stationary. "
Hoping to learn here: Anyone else have this as a "normal" event when starting an R44. I learned in, and then flew for a few years a number of Raven II models (also owned one myself) and never saw the CO2 light illuminated other than in "Test" mode. The school also had several Raven II machines, and the only one I heard of which had an illuminated CO2 light other than in "Test" was shut-down and withdrawn from service first time it happened; turned out to have a cracked exhaust manifold and once repaired it never did that again.
I can theorize how it might occur - starting with a tail wind?- but is this actually "normal"?
Thanks
Hoping to learn here: Anyone else have this as a "normal" event when starting an R44. I learned in, and then flew for a few years a number of Raven II models (also owned one myself) and never saw the CO2 light illuminated other than in "Test" mode. The school also had several Raven II machines, and the only one I heard of which had an illuminated CO2 light other than in "Test" was shut-down and withdrawn from service first time it happened; turned out to have a cracked exhaust manifold and once repaired it never did that again.
I can theorize how it might occur - starting with a tail wind?- but is this actually "normal"?
Thanks
A bit of cut and paste by the AAIB as they have given the same description to both incidents - helicopter rollover at Sherburn.
2 lucky pilots - presumably the R44 student has learned to secure items in the cockpit BEFORE starting up so it can be done properly and the 109 pilot has learned that 'gates' are there for a reason and if you don't make the gate then go around.
John R81 - Carbon Monoxide isn't CO2 but |I'm sure you know that
2 lucky pilots - presumably the R44 student has learned to secure items in the cockpit BEFORE starting up so it can be done properly and the 109 pilot has learned that 'gates' are there for a reason and if you don't make the gate then go around.
John R81 - Carbon Monoxide isn't CO2 but |I'm sure you know that
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John--not "normal" per se, but under certain wind conditions it can and does happen on rare occasions. This is a situation, i.e. ingestion of exhaust into a cabin vent, that could happen on any piston engine helicopter when hovering or just sitting on the ground. It's actually nice that the CO detector is standard equipment because it alerts you to a situation that would otherwise go unrecognized. I've only had it happen to me once, while doing some hovering patterns on a cold day with all doors on and the main cabin air vent, the inlet for which is located at the nose of the aircraft in front of the instrument panel, open just a little. I've never heard of it happening with a door or two off.
The POH, Section 3, states "Shut off heater and open nose and door vents. If hovering, land or transition to forward flight. If symptoms of CO poisoning (headache, drowsiness, dizziness) accompany light, land immediately."
In my case I opened all the vents and flew around the hover area for a few seconds--problem solved. It probably would have been just as easily solved if there had been someone to crack open a door. If you get, say, the classic muffler heat shroud exhaust leak this is something that would rear it's ugly head in phases of flight other than sitting on the skids or hovering with some sort of unfortunately wind conditions.
I am only personally aware of one other incidence of this, which happened to another pilot colleague under very similar situations to mine.
The POH, Section 3, states "Shut off heater and open nose and door vents. If hovering, land or transition to forward flight. If symptoms of CO poisoning (headache, drowsiness, dizziness) accompany light, land immediately."
In my case I opened all the vents and flew around the hover area for a few seconds--problem solved. It probably would have been just as easily solved if there had been someone to crack open a door. If you get, say, the classic muffler heat shroud exhaust leak this is something that would rear it's ugly head in phases of flight other than sitting on the skids or hovering with some sort of unfortunately wind conditions.
I am only personally aware of one other incidence of this, which happened to another pilot colleague under very similar situations to mine.
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I've had CO light on several times over the years.
Prolonged time engine running on the ground, or hovering, with a tail wind.
Transition to forward flight and light goes out.
At least it shows that the sensor is working!
Prolonged time engine running on the ground, or hovering, with a tail wind.
Transition to forward flight and light goes out.
At least it shows that the sensor is working!
