Sensorcon Inspector CO Detector Endorsement

[yvesg]

If someone realizes that heir CO detector shows around 100 PPM at altitude and they are on supplementary oxygen, is it as bad an emergency as if you were not on supp?

Would you decent in a hurry in such situation or just keep cool since you get good stuff through the nostrils.

Yves

[Rick Junkin]

I'm sure one of the doctors here can answer authoritatively.

Personally I would be thinking about getting on the ground as soon as possible. You're using supplemental O2 because of the rarified air at altitude, so you aren't getting any "extra" O2, just what you need to keep your O2 saturation at normal levels. CO attaches more readily than O2 under NORMAL conditions, and according to the studies I've read there is evidence that you are at a higher risk with CO exposure at altitude. You can only get to 100% O2 saturation (I think?) with supplemental oxygen and CO at sufficient levels will still win over the O2 from what I understand. Lots of hemming and hawing here, as I think I only know enough to be dangerous on this topic.

The exception would be if you were using a sealed mask from an O2 bottle and not pulling in any ambient cockpit air, in which case you will have isolated yourself from the CO in the cockpit. I'd get on the ground as soon as practical, rather than as soon as possible, in that case.

These are only my opinions, looking forward to being educated by those who have done more than read studies.

Cheers,
Rick

[DanM20C]

1 hour ago, yvesg said:

If someone realizes that heir CO detector shows around 100 PPM at altitude and they are on supplementary oxygen, is it as bad an emergency as if you were not on supp?

Would you decent in a hurry in such situation or just keep cool since you get good stuff through the nostrils.

Yves

I think that depends on the source.  All the CO detector is really doing is alerting us to an abnormally in out exhaust system.  The 100ppm could be a pin hole muffler were we simply turn the heat off and land when convenient.  Or on a turbo it could be a failing v-band clamp that could turn into a serious emergency 15 min later.

These CO detectors, that give us a high resolution PPM readout, can be looked at similar to an engine monitor. It’s one more tool that may show signs of an issue before it’s a real problem. 

If I had O2 on and saw a rise in CO, I would crank up the flow of O2, start troubleshooting the CO, and make a plan to land.

cheers,

Dan

[Andy95W]

I think I would be more concerned if I were on supplemental oxygen, unless it was through a fully sealed face mask.

The flow of oxygen in a supplemental system is only a small part of what is taken into the lungs, particularly through a cannula type nostril system.  It only increases the relative percentage of oxygen that is available to the lungs, thus ensuring more O2 molecules are available to be absorbed.  The rest is ambient air, which in this scenario, contains carbon monoxide.

The transport mechanism for oxygen molecules is the hemoglobin in the blood.  Hemoglobin has an affinity to transport carbon monoxide molecules 230 times greater than oxygen molecules.

[Rick Junkin]

EPILOGUE PART ONE

I recovered N1088F from Tennessee back to St Louis this afternoon. The Sensorcon alerted again (35+PPM) on climb out, but immediately dropped into the teens when I opened the cockpit vent on the console. I already had the overhead vent open. I leveled at my flight planned altitude of 4000' to fly between cloud layers and the CO level dropped to 0. I closed all of the vents and opened the heater, and the CO level stayed at 0 for the rest of the flight.

I'm thinking that I have some spots on the belly or in the left wheel well that are allowing exhaust into the cockpit at climb angle of attack, as pointed out to me by Don Maxwell and others on the MAPA mailing list. Tom (my mechanic) and I will be taking a look on Friday if it isn't too cold. There's more to this story, I think.

Cheers,
Rick

[mike_elliott]

12 hours ago, Junkman said:

EPILOGUE PART ONE

I recovered N1088F from Tennessee back to St Louis this afternoon. The Sensorcon alerted again (35+PPM) on climb out, but immediately dropped into the teens when I opened the cockpit vent on the console. I already had the overhead vent open. I leveled at my flight planned altitude of 4000' to fly between cloud layers and the CO level dropped to 0. I closed all of the vents and opened the heater, and the CO level stayed at 0 for the rest of the flight.

I'm thinking that I have some spots on the belly or in the left wheel well that are allowing exhaust into the cockpit at climb angle of attack, as pointed out to me by Don Maxwell and others on the MAPA mailing list. Tom (my mechanic) and I will be taking a look on Friday if it isn't too cold. There's more to this story, I think.

Cheers,
Rick

At least you know the heat muff isnt being pumped full of co like in Dan's case. Rick, you could use your sensorcon as a "detector" to find the source. Fire that sucker up and move the sensorcon around in ea. foot well,  etc and see where it starts to register high at.

 

[carusoam]

Things to know about PPMs and CO...

1) parts per million is a percentage reading of the CO in the air that the sensor is reading.

2) The sensor doesn't change accuracy much with altitude.

3) The human body is altitude sensitive.

4) CO takes a long time to get flushed out of the blood. It collects over time and takes hours to go away.

5) red blood cells blocked with CO are unable to carry O2.  

6) If you see elevated levels of CO on the meter, you want to keep this from happening, because even small elevated numbers shown, the  CO will be blocking O2 preferentially...

7) The finger tip %O2 devices can't discern CO from O2, leading to good looking but very false readings...

8) Looking at the human body's sensitivity to CO at altitude, consider the following...

• Without CO, the brain has Decision difficulty as the amount/pressure of O2 becomes less
• The FAA has give guidelines that generally work.
• The finger tip O2 gauge gives further personalization of the FAA guidance. 
• %O2 levels below 90% begin the onset cognitive challenges for many people.

9) Expect, If you are at 90% O2 saturation normally, flying at altitude without supplemental O2... blocking out an additional few percent of those red blood cells brings you into a lower %O2 level...

 

Briefly...

• CO circulating in your breathing air is bad, because it’s preferential sticking to hemoglobin and staying stuck there for a long time.
• finger tip %O2 gauges Don't show CO problem at all, and give misleading/incorrect %O2 instead...
• CO meter is a reliable method of knowing the CO level.
• Sensors are not very altitude dependent.
• Human body is very altitude dependent.
• A human body at altitude with CO poison will be even more altitude dependent.
• TC'd engines can keep climbing to where air is very thin.  An even more harsh place to have a CO challenge.
• breathing high levels of O2 comes with its own challenges.
• Nothing better than fresh air...
• Nothing more challenging than making decisions while being cognitively challenged.
• having the ability to descend and level out automatically at a safe altitude can be helpful.
• Slightly Elevated CO levels on the ground are expected.  But, not in flight.
• If you have Elevated CO levels, the source will probably be easy for a mechanic to find.

PP thoughts only.  Not a mechanic or a Dr... but I did read a lot of MS while staying at a Holiday Inn....

Best regards,

-a-

[Rick Junkin]

On 12/22/2017 at 3:07 AM, Raptor05121 said:

On the declaring part, what extra follow-up comes from that? Any phone calls? Paperwork to deal with?

I got a very pleasant follow-up call from the Memphis FSDO while I was walking in to work this morning. The gentleman told me what information he had regarding the incident, and essentially asked me to fill in the details on the event and subsequent maintenance performed to remedy the problem. Took about three minutes, with shared well wishes for the new year. No paperwork requested on this one.

Cheers,
Rick

[thinwing]

Hi there..have you noticed the whitish exhaust trail running down the pilots side of the fuselage?This shows how closely the exhaust stream plays across the belly.On takeoff the mixture at 34/25 or 24 is very rich and non stoichometric,i.e. Very rich in CO compared to lean condition...on takeoff the angle of attack is such that CO tracks the fuselage and enters the wheel wells,gascolator drain hole and if your belly panel sealing is shot you get increased CO in the cockpit...( I used to routinely see 200 ppm on climbout)fully open cowl flaps seem to make the problem worse..I think they create a burble...regardless I believe unless you can get perfect sealing you will always see some CO on climbout with the CO going away after leveling off ,leaning and closing cowlflaps.So what is the effect of exposure to 100 or 200 ppm CO for 30 mins while climbing and than dropping to zero for the rest of flight?Not good but also not life threatening....the federal work force rules limit exposure based on constant exposure...My recommendation ,however ,is to make sure all three belly panes have a good rtv seal along there edges...also check your gear and aileron boots...where the enter the belly area.You won't be able to get a complete seal however..the trim wheel is a big opening.Check for cold spots under the seats..especially copilot...Use your CO sensor to Map hot spots.Close the pilot and copilot air vents..open the vents in the ceiling every takeoff...be prepared to see some CO,every takeoff in the Bravo.

[jetdriven]

Do you seal those tunnel floor board panels? 

[jetdriven]

On 12/25/2017 at 10:27 PM, DanM20C said:

The 100ppm could be a pin hole muffler were we simply turn the heat off and land when convenient.  Or on a turbo it could be a failing v-band clamp that could turn into a serious emergency 15 min later.......

cheers,

Dan

Some of those turbo v band clamps fail and it incapacitates the pilot in 1 minute. Faster than they can turn the plane around on takeoff and land. It’s serious business. 

[DanM20C]

25 minutes ago, jetdriven said:

Some of those turbo v band clamps fail and it incapacitates the pilot in 1 minute. Faster than they can turn the plane around on takeoff and land. It’s serious business. 

Yes, when they let go it's bad news. 

Back in September I was preflighting my new(to me) 231 and noticed the v band on the hot side (intake) had rotated about 30 degrees from the last preflight.  I saw no abnormal CO readings on the Sensorcon the flight before.  I elected not to fly and ordered new clamps.  

 

22 hours ago, thinwing said:

( I used to routinely see 200 ppm on climbout)

This is interesting.  Lots of people have been reporting to me what their readings have been in various airplanes.  Many show some CO during climb but I haven't heard of any being consistently higher than 50 ppm.   I wonder if this is common in Bravos?  I would think with the heater on or some vents open there would be enough positive pressure in the cockpit to keep the CO out.

My K shows 2-5 ppm on taxi and run up(occasionally  higher with certain winds) and 0 for all phases of flight.

Cheers,

Dan      

[MyNameIsNobody]

On 1/4/2018 at 10:45 PM, thinwing said:

Hi there..have you noticed the whitish exhaust trail running down the pilots side of the fuselage?This shows how closely the exhaust stream plays across the belly.On takeoff the mixture at 34/25 or 24 is very rich and non stoichometric,i.e. Very rich in CO compared to lean condition...on takeoff the angle of attack is such that CO tracks the fuselage and enters the wheel wells,gascolator drain hole and if your belly panel sealing is shot you get increased CO in the cockpit...( I used to routinely see 200 ppm on climbout)fully open cowl flaps seem to make the problem worse..I think they create a burble...regardless I believe unless you can get perfect sealing you will always see some CO on climbout with the CO going away after leveling off ,leaning and closing cowlflaps.So what is the effect of exposure to 100 or 200 ppm CO for 30 mins while climbing and than dropping to zero for the rest of flight?Not good but also not life threatening....the federal work force rules limit exposure based on constant exposure...My recommendation ,however ,is to make sure all three belly panes have a good rtv seal along there edges...also check your gear and aileron boots...where the enter the belly area.You won't be able to get a complete seal however..the trim wheel is a big opening.Check for cold spots under the seats..especially copilot...Use your CO sensor to Map hot spots.Close the pilot and copilot air vents..open the vents in the ceiling every takeoff...be prepared to see some CO,every takeoff in the Bravo.

200PPM?  No Bueno.  That is a reason NOT to own a Bravo.  That is a completely unacceptable level of CO.  The Pox to that...

[M016576]

I have a sensorcon unit- and regarding their use at altitude, the question came up in my mind-

if I’m at altitude and the air is thinner, but by volume, I’m emitting a similar amount of CO... wouldn’t that exacerbate a common reading in the cockpit (if one had a leak, and the conditions of flight were the same- AoA, speed, etc)?  So at lower altitudes, the PPM would naturally be less, because the atmosphere is more “prevelant” than the CO emissions, assuming they remained constant as altitude increased?  Wouldn’t that make the sensorcon unit more “sensitive” at altitude? Or more prone to showing a leak as altitude increased?

just a thought... no sure how the sensor in the sensorcon unit actually works- so it would be Interesting to me to know if this is the case, even though it wouldn’t really effect my operations with the unit.

[gsxrpilot]

On a recent flight of mine at FL230, I was checking the SensorCon on a regular schedule just like I was checking the PulseOx. It stayed at 0 the whole time, but I kept checking.

[mike_elliott]

8 hours ago, MyNameIsNobody said:

200PPM?  No Bueno.  That is a reason NOT to own a Bravo.  That is a completely unacceptable level of CO.  The Pox to that

Lets keep this in perspective, this is not a BRAVO problem, but a plane maintenance problem.

[Danb]

10 hours ago, DanM20C said:

Yes, when they let go it's bad news. 

Back in September I was preflighting my new(to me) 231 and noticed the v band on the hot side (intake) had rotated about 30 degrees from the last preflight.  I saw no abnormal CO readings on the Sensorcon the flight before.  I elected not to fly and ordered new clamps.  

 

This is interesting.  Lots of people have been reporting to me what their readings have been in various airplanes.  Many show some CO during climb but I haven't heard of any being consistently higher than 50 ppm.   I wonder if this is common in Bravos?  I would think with the heater on or some vents open there would be enough positive pressure in the cockpit to keep the CO out.

My K shows 2-5 ppm on taxi and run up(occasionally  higher with certain winds) and 0 for all phases of flight.

Cheers,

Dan      

Dan I don't think it's common among bravos or at least not mine, I show co levels on the ground, but on climbout my sensorcon reads zero, I'd be beyond concerned if my levels approximated thin wings. I'll continue monitoring and report any problems 

[Rick Junkin]

3 hours ago, mike_elliott said:

Lets keep this in perspective, this is not a BRAVO problem, but a plane maintenance problem.

 

3 hours ago, Danb said:

I'd be beyond concerned if my levels approximated thin wings.

Concur with both.

RE: MAINTENANCE. I did a quick look at the belly of the airplane and I found a couple of camlocs had pulled through on one of my belly panels (the large one) and I'm thinking the open holes could be the source of the CO infiltration during climb. I need to drop the panels and have a further look inside and retrieve the pulled-through camlocs, but it was still too dang cold for me to get in to that. I won't be able to get to the hangar again for about a week and a half. Hopefully the temps will be back above the teens by then and I can affect some repairs/replacements and resealing and get her out for a check flight.

RE: CO LEVELS. The only time I had seen an alert on my Sensorcon prior to this incident was when I had put the sensor in the back seat with my flight bag when refueling after a trip with my wife, and she was holding the door open during the taxi back to the hangar. To be expected, right? It also gave me a warm fuzzy that I could hear the alarm over the normal cockpit noise. Every other time I had looked at the sensor it read between 0 and 17, with 17 being during ground ops with the pilot window open. I don't stare at it, or constantly check it, or run it in MAX mode, so it could be that there were higher levels that I just didn't see, but not high enough to cause an alarm. And the preset alarm on the sensor is set at a conservative 35PPM, the level deemed acceptable, by the people who are supposed to know about this stuff, for regularly experiencing 8 hours of exposure during a normal work shift. What levels you're wiling to fly with is your decision.

And that's where I'm going with this. If you read through the posts on the CO threads you'll see a pattern of "normal" levels you should expect to see during different phases of ground and flight operations. Generally speaking the reported levels are between 0 and the high teens. If the levels you are seeing exceed these by a significant margin, you may want to take some time, as several people have done and reported here, to take a look and see if you can figure out why. The most significant thing about the PPM number that your sensor is reporting, other than if it gets high enough to alert you to imminent danger, is that your numbers are within the norms and that THEY AREN'T CHANGING. In my case I had never seen anything higher than 17PPM, and now something has changed and the alarm is going off. I can't find a way to get the level back down to normal, so there is something wrong and I don't know what it is or if it will get worse. SHOULD I continue is the question that led me to the decision to get back on the ground and investigate. I briefly flirted with the question of CAN I continue, but quickly determined that there would be a lot of workload in dealing with future contingencies, potentially in a diminished decision making capacity, and there was no justification for taking that risk. Something was not right with my airplane and it could hurt me, I couldn't find a way to mitigate it, so it was time to get back to zero knots where I could devote all of my attention to finding the problem.

My level of experience with this airplane factored in as well. I only have 120 hours in my Mooney and while I've seen some unusual things that I've worked through, I still have a lot to learn and experience. Looking at this in retrospect, if it were to happen again and I had closed the heater/defrost, opened vents, etc I would reduce the angle of attack (increase speed) and see if that changed the CO PPM trend. One more troubleshooting technique to put in the tool kit. But once the level climbed through 100PPM my focus shifted completely away from troubleshooting and on to getting the airplane on the ground. That was as far as I was willing to let it go with a reasonable expectation of being able to continue to fly the airplane competently through a successful recovery. You can look at the available charts and data and determine where your own limit is.

FWIW, my daughter's boyfriend is a St Louis firefighter, and we talked about CO poisoning over the Christmas holiday. The St Louis fire department uses 100PPM as the trigger for evacuating a home or building. One more piece of data to consider.

Cheers,
Rick

 

[thinwing]

On 1/6/2018 at 5:34 AM, mike_elliott said:

Lets keep this in perspective, this is not a BRAVO problem, but a plane maintenance problem.

Exactly...my point is that rtf seal on the belly panels is important!There is an interplay between the cowl flap and the single exhaust pipe on the pilots side that creates a burbling effect on takeoff,full throttle,full rich and cowl flaps fully open ,climb attitude.The CO is coming from the exhaust stream and is normal byproduct...but in the Bravo if your belly panels have gaps because sealant is gone...exhaust gas can seep into belly space and than into cabin.This seems to go away when aircraft is leveled for cruise ,leaned out and cowl flaps at least partially closed.What I think than happens is that exhaust stream separates from belly and no longer enters...I found no problems fire wall forward but after I resealed the panel edges ,the problem went away.The Bravo isn't the only aircraft I've seen high CO...the worst was a husky on amphib floats!Pitts S1S in a hammer head would stink you out!

[Matthew]

Not a Mooney, but I have the Sensorcon in my Comanche - bought it after the big story of the CO poisoning on here a while back.

I keep mine clipped to the panel, on the copilot's side. During runup/taxi, I will get indications up to ~60 PPM, but in flight it remains at 0. I have the dual exhaust stacks and haven't located the problem yet - but without the CO detector, I'd have no idea I should be looking!

[carusoam]

Great first post, ma!

Best regards,

-a-

 

 

[Matthew]

15 hours ago, carusoam said:

Great first post, ma!

Best regards,

-a-

 

 

Thanks! I've been a long time lurker - before getting the Comanche, I was Mooney shopping. I even got an intro flight from @rbridges!

[Matthew]

3 hours ago, Hyett6420 said:

Just received my sensorcon.  5 days from the USA to your ancestors, not bad, great service by them and delivery was cheap too.   Now just need to fit it.  

The previous owner of my plane had a little holder for CO strips.

The Sensorcon clip fits perfectly into the holder... slapped it on like this the day I bought it and haven't moved it since... works great (yes, I know there are better ways to do this)!

PS ... I am not sure it's actually turned on in the photograph. D'oh!  Tip: Don't be like me, add "turn on CO detector" to your checklist!

Edited January 10, 2018 by Matthew

[Alan Fox]

I hang mine on the door pull , when taxiing out , it can go as high as 8 , but in landing phase from rollout to taxi , it can go as high as 50 or so.... In cruise it is 0 , I have an 83 J , has anybody figured out where it enters the cabin from the outside , as I would like to see it at 0 and stay there .... In the Bonanza , it is always at 0......

[Raptor05121]

I think it comes in from the wing to fuselage fairings. Just a guess. I have heard there is supposed to be tape under the seals?