CO levels in Cirri

Guest Discussion
1

I am considering the purchase of an SR-22, and have a question about CO. Recently I bought an AIM-935 as recommended on AVWeb to monitor CO levels in the Diamond Katana’s I’m training in. I’ve been surprised to see levels from 7-30ppm in various stages of flight in planes across the line. I’m wondering if anyone has carried a low-level CO monitor in their Cirrus to see what the levels are.

In the Katana, the exhaust is not far from the cabin air intakes and certain flight attitudes seem to be worse than others.

For comparison, when I start my car in my garage with the door open and back out, levels in the car rise to the 10-12ppm range. Idleing on a freeway in rush hour traffic can also rise to the 7-12ppm area. Most home CO detectors do not sound until at least 35ppm. The AVWeb article on CO is at:

http://www.avweb.com/articles/codetect/

Curtis Sanford

San Francisco

2

I am considering the purchase of an SR-22, and have a question about CO. Recently I bought an AIM-935 as recommended on AVWeb to monitor CO levels in the Diamond Katana’s I’m training in. I’ve been surprised to see levels from 7-30ppm in various stages of flight in planes across the line. I’m wondering if anyone has carried a low-level CO monitor in their Cirrus to see what the levels are.

In the Katana, the exhaust is not far from the cabin air intakes and certain flight attitudes seem to be worse than others.

For comparison, when I start my car in my garage with the door open and back out, levels in the car rise to the 10-12ppm range. Idleing on a freeway in rush hour traffic can also rise to the 7-12ppm area. Most home CO detectors do not sound until at least 35ppm. The AVWeb article on CO is at:

http://www.avweb.com/articles/codetect/

Curtis Sanford

San Francisco

Curtis,

I’m not real happy with the CO detector (I have the same one - AIM 935).

The first one I bought, on the way back from Duluth, went from “Lo” to 35 ppm, then back to “Lo”, then hovered around 10-11 for a while, then back over 20, etc. within the span of about 30 minutes, with no changes in ventilation, mixture, throttle, altitude, etc. When it went above 30, I was just about to decend and make a precautionary landing at the nearest airport to have it checked out (while still in Minnesota at least) when it started decreasing again.

I returned that one (the folks at Aeromedix were very accomodating) and got a replacement, thinking that there was just something wrong with that one.

The one I have now is a little more consistent, but quite often does go above the threshold for beeping (I think it’s 9 ppm, but I don’t remember). I often see readings in the mid teens, although just as often I see readings of “Lo”. Can’t seem to correlate it to any particular throttle setting, ventilation setting, attitude, etc. Just seems random.

Like you, I’ve often seen these “teen” readings in other planes, too. So I have to accept this as “normal”. Plus I don’t think that even a few hours exposure to mid-teen level CO will do any harm.

The problem is that because it starts beeping at such a (relatively) low level, it’s sort of like the boy who cried wolf – I’m so used to it beeping that I just ignore it, and am considering not even carrying it anymore since it’s so annoying.

Given what I’ve seen in planes so far, I think I’d prefer having one that only beeps above say 20-25 ppm - at least then I’d KNOW I have a problem and can start making plans to get down right away.

I don’t think this helps answer your question very much but it did allow me to vent! :slight_smile:

Steve

3

I am considering the purchase of an SR-22, and have a question about CO. Recently I bought an AIM-935 as recommended on AVWeb to monitor CO levels in the Diamond Katana’s I’m training in. I’ve been surprised to see levels from 7-30ppm in various stages of flight in planes across the line. I’m wondering if anyone has carried a low-level CO monitor in their Cirrus to see what the levels are.

I’ve had the AIM-696 unit for a few years. I used

to see low levels in the tigers I rented. In a friend’s tiger (which had a CO leak) we saw much

higher readings, so the unit appeared to me to be

reasonably accurate. In our club’s Cirrus, only
once have I gotten a reading other than 0.

Incidentally, I picked up the following from another list.

An up-date on the AIM 935/696 CO monitors:

Since the company was recently purchased, the residential line will no

longer be developed or sold. They are, however, tooling up to cover

warrantee units for replacement…now a 2 month+ wait. Realizing that

these units (esp. the low level 935) are the BEST bang for the buck,-

especially for our canopied Grummans (topic relevant), I contacted

George Kerr, the brains and residential line developer at his ranch in

Missouri.

Seems he and an associate have just acquired the the residential line

and will be up and running in ~ 60 days. He is a most knowledgable and

savvy gentleman well versed in the residential/aircraft marketplace.

Anyone interested in either of these units may contact George directly:

[email]gekerr@tds.net[/email]

800-643-5377

888-443-5377

4

I’ve got the 935 unit as well. I get very occasional nuisance alerts, but not often enough to piss me off. The one case where I do consistently set it off is while taxiing with the door open, which I guess is not too surprising.

5

Curtis, let me try to put some of this in perspective for you and the other folks on this forum…

First, CO concentration readings of 7-30 PPM are well within the FAA requirements for newly-certified airplanes under FAR Part 23. For certification testing, the FAA requires only that CO concentrations in the cabin do not exceed 50 PPM. I happen to think that standard is way too loose, but that’s what’s in Part 23.

(CAR 3, the predecessor of Part 23 and the rules under which the vast majority of today’s single-engine piston fleet was certified – Bonanzas, Cessnas, Mooneys, Pipers, etc. – had no CO testing requirements at all, so Part 23 is certainly a huge improvement in that regard.)

It’s important to keep in mind that the effects of CO on the bloodstream are a function of two variables: CO concentration (as measured by your CO monitor) and time of exposure. A concentration of 100 PPM of CO is inconsequential if you’re only exposed to it for a minute or two. A concentration of 30 PPM could be highly significant if you were exposed to it for 24 hours.

A third important variable that has not been studied adequately is cabin altitude. Although profound CO poisoning can make you quite ill to the point of physical incapacitation (and even death in extreme cases), as airmen we should also be quite concerned by the effects of low-level CO poisoning on our cognitive abilities that affect our performance and judgement as flight crew members. CO poisoning affects cognitive function by interfering with the ability of our red blood cells to carry oxygen to the brain. In short, it produces a form of hypoxia (known tecnically as “hypemic hypoxia”). But we all know that flying in unpressurized aircraft at cabin altitudes well above those to which our bodies are acclimated also causes hypoxia (variously termed “altitude hypoxia” or “hypoxic hypoxia”) which also reduces the supply of oxygen to the brain. Common sense would suggest that the effects of CO-induced hypoxia and altitude-induced hypoxia are cumulative, but very little research has been done on this to date.

(I’m happy to see that the FAA Civil Aeromedical Institude is finally doing a study on this issue, focused specifically on the question on the degree to which pilots who smoke before flight – and thereby subject themselves to mild CO poisioning – have degraded performance at altitude compared to non-smoker pilots. See http://www.cami.jccbi.gov/AAM-500/hypoxia.html)

While we’re waiting for the research results, I’d suggest we apply a common-sense approach to CO in the cockpit. I’d offer the following guidelines:

  1. Cockpit CO concentrations greater than 35 to 50 PPM for period exceeding a few minutes are unacceptable. If such concentrations are observed on the ground and cannot be corrected immediately (see below), don’t take off. If such concentrations are observed in flight, land immediately. (The FAA says 50 PPM, I’d prefer 35 PPM, take your pick.)

  2. The hazard created by low levels of CO contamination in the cockpit rise rapidly at cabin altitudes above 8,000 feet. In my opinion, even concentrations of 10 or 20 PPM should be cause for concern if you’re flying at 11,000 feet. If this occurs, I’d advise you either to descend immediately or to go on oxygen (and use a mask, NOT a cannula).

  3. Many aircraft register significant CO concentrations in the cabin during ground operations. In most cases, this can be substantially reduced by proper engine leaning. As a general rule, aircraft piston engines should NOT be operated at full-rich during ground operations, but should be leaned to the point of maximum RPM rise. Doing so typically results in a precipitous drop in the CO content of engine exhaust. Keep in mind that CO results from INCOMPLETE combustion, and a rich mixture causes incomplete combustion because there’s not enough oxygen to support complete combustion. (Opening cabin air vents and/or turning on ventilation blowers may also help … or may make things worse, depending on the particular aircraft.)

  4. UL-2034-approved CO detectors like the AIM 696 do not register CO concentrations below 35 PPM on their digital readouts. Although some pilots prefer this, I much prefer a highly-sensitive CO monitor that registers concentrations down to 10 PPM or less. Even though very low CO concentrations may not be hazardous – particularly if they occur only during short-lasting phases of flight operation – I would prefer to know about them, and to be able to try things (like opening vents, turning on blowers, leaning the mixture, etc.) to see if they can be reduced or eliminated. But maybe that’s just me.

On another subject, I can confirm that the U.S. company (IST) that acquired AIM (of Canada) last year has indeed announced that they’re getting out of the consumer products business altogether, including discontinuing manufacture of the AIM 696 and 935 products. Aeromedix.com is working hard to fill the void created by the withdrawal of these products, and should have an announcement on this quite soon. Meantime, IST-AIM has committed to honor the warranty on all AIM 696 and 935 units presently in the field.

6

Curtis, Steve…

I also have an AIM-935, and my experience is about the same as yours. Lots of nuisance alarms. I was assuming that the unit has a more urgent, faster beep when the level gets higher - but I can’t seem to find the book that came with the unit. If all the alarms sound the same, I might as well chuck the unit, since I’m ignoring the low level alarms anyway.

Mike.

7

I am considering the purchase of an SR-22, and have a question about CO. Recently I bought an AIM-935 as recommended on AVWeb to monitor CO levels in the Diamond Katana’s I’m training in. I’ve been surprised to see levels from 7-30ppm in various stages of flight in planes across the line. I’m wondering if anyone has carried a low-level CO monitor in their Cirrus to see what the levels are.

In the Katana, the exhaust is not far from the cabin air intakes and certain flight attitudes seem to be worse than others.

For comparison, when I start my car in my garage with the door open and back out, levels in the car rise to the 10-12ppm range. Idleing on a freeway in rush hour traffic can also rise to the 7-12ppm area. Most home CO detectors do not sound until at least 35ppm. The AVWeb article on CO is at:

http://www.avweb.com/articles/codetect/

Curtis Sanford

San Francisco

Curtis,

I’m not real happy with the CO detector (I have the same one - AIM 935).

The first one I bought, on the way back from Duluth, went from “Lo” to 35 ppm, then back to “Lo”, then hovered around 10-11 for a while, then back over 20, etc. within the span of about 30 minutes, with no changes in ventilation, mixture, throttle, altitude, etc. When it went above 30, I was just about to decend and make a precautionary landing at the nearest airport to have it checked out (while still in Minnesota at least) when it started decreasing again.

I returned that one (the folks at Aeromedix were very accomodating) and got a replacement, thinking that there was just something wrong with that one.

The one I have now is a little more consistent, but quite often does go above the threshold for beeping (I think it’s 9 ppm, but I don’t remember). I often see readings in the mid teens, although just as often I see readings of “Lo”. Can’t seem to correlate it to any particular throttle setting, ventilation setting, attitude, etc. Just seems random.

Like you, I’ve often seen these “teen” readings in other planes, too. So I have to accept this as “normal”. Plus I don’t think that even a few hours exposure to mid-teen level CO will do any harm.

The problem is that because it starts beeping at such a (relatively) low level, it’s sort of like the boy who cried wolf – I’m so used to it beeping that I just ignore it, and am considering not even carrying it anymore since it’s so annoying.

Given what I’ve seen in planes so far, I think I’d prefer having one that only beeps above say 20-25 ppm - at least then I’d KNOW I have a problem and can start making plans to get down right away.

I don’t think this helps answer your question very much but it did allow me to vent! :slight_smile:

Steve

I had the same problems, then the unit went kaput. It was nearly impossible to get through to customer service. Three weeks ago they promised to send me a new one. The bad news: still waiting. The good news: they’re crummy units anyway!

8

So this is interesting; are we saying that across a reasonable sample of piston planes, we’ve never seen a plane that didn’t report these low but measureable CO levels? I wonder if the factory has a view on ‘normal’ CO levels.

(I can report that in 10 hours of flying in a Citation Bravo, the detector never made a peep; I guess $5M does buy you something…)

9

I can also report that I thought there was something wrong with the unit since it never reported anything beside 0 during about 500 hours in a Piper Cheyenne, but one day in the garage it went wild. Called the company and they were very nice and send a new one, I put the old one in the hangar and for the last six months it has beeped every 1 minute and still going strong. I was asked what that sound was and I told them it was an alarm system for the hangar. Who knows it may be serving a different purpose now that the unit is dead but keeping the good guys from turning bad.

Have a great day.

Cirrus that is…

Woor

So this is interesting; are we saying that across a reasonable sample of piston planes, we’ve never seen a plane that didn’t report these low but measureable CO levels? I wonder if the factory has a view on ‘normal’ CO levels.

(I can report that in 10 hours of flying in a Citation Bravo, the detector never made a peep; I guess $5M does buy you something…)

10

Curtis,

So this is interesting; are we saying that across a reasonable sample of piston planes, we’ve never seen a plane that didn’t report these low but measureable CO levels?
I think you’re right - I have one other data point, which is from flying a single-engined Commander with an AIM-935 on board. Same story - frequent low-level alerts.
I wonder if the factory has a view on ‘normal’ CO levels.
We may find out. N84MR is going in for scheduled maintenance next week; the CO level is on my list of things to check. I’m expecting a response of “CO levels checked, found to be normal”.
My guess is that it is more or less normal when you’re sitting directly behind the engine. Perhaps “!!!” or “Jeff” or “Gluedude” can tell us about internal plans to produce an SR-2X with an aft-mounted engine. :wink:

  • Mike.

PS - Will swap my SR20 for your Citation Bravo, sight unseen!

  • Mike.
11

I have had an AIM unit in my SR20 from the very first day, and after 160 hours, have never seen anything but 0 on it. However, based on the replies above, Im wondering if the unit is operating correctly. But it blinks like its supposed to…

12

I have had an AIM unit in my SR20 from the very first day, and after 160 hours, have never seen anything but 0 on it. However, based on the replies above, Im wondering if the unit is operating correctly. But it blinks like its supposed to…

Just hold it in the exhaust stream from a car for a few seconds and you’ll know if it works.

-Curt

13

Just hold it in the exhaust stream from a car for a few seconds and you’ll know if it works.

Unless you own a Honda. Maryland requires an emission test on a dynometer every 2 years and I have never seen a number over 0 for CO on any of my Hondas.

14

Curtis,

I wonder if the factory has a view on ‘normal’ CO levels.

We may find out. N84MR is going in for scheduled maintenance next week; the CO level is on my list of things to check. I’m expecting a response of “CO levels checked, found to be normal”.

  • Mike.

Mike, you may want to lend them your 935; it is likely to be more sensitive than what they are using.

PS - Will swap my SR20 for your Citation Bravo, sight unseen!

Alas, it is not mine, but a good friend’s. He’s pretty excited about seeing the SR22 so I’ll see what I can do. He may be spooked by the CO.

-Curt

15

Curtis, let me try to put some of this in perspective for you and the other folks on this forum…

Mike,

Thanks for the information & advice regarding CO. I’m willing to bet that this entire thread on CO would probably not have been brought up (and we wouldn’t even be thinking about it) if not for your articles on Avweb - so thanks for bringing up these types of issues.

Just wanted to point out, since I’m sure it will come up, that this Mike Busch (of AvWeb) is NOT the Mike Busch of Cirrus that we all talk to with our squawks… (at least, as far as I know they’re not the same person!) – when I first saw the name “Mike Busch” I was surprised 'cuz I thought it was the Cirrus Mike commenting publicly on this ‘unofficial’ board!

Steve

16

Curtis, let me try to put some of this in perspective for you and the other folks on this forum…

First, CO concentration readings of 7-30 PPM are well within the FAA requirements for newly-certified airplanes under FAR Part 23. For certification testing, the FAA requires only that CO concentrations in the cabin do not exceed 50 PPM. I happen to think that standard is way too loose, but that’s what’s in Part 23.

(CAR 3, the predecessor of Part 23 and the rules under which the vast majority of today’s single-engine piston fleet was certified – Bonanzas, Cessnas, Mooneys, Pipers, etc. – had no CO testing requirements at all, so Part 23 is certainly a huge improvement in that regard.)

It’s important to keep in mind that the effects of CO on the bloodstream are a function of two variables: CO concentration (as measured by your CO monitor) and time of exposure. A concentration of 100 PPM of CO is inconsequential if you’re only exposed to it for a minute or two. A concentration of 30 PPM could be highly significant if you were exposed to it for 24 hours.

A third important variable that has not been studied adequately is cabin altitude. Although profound CO poisoning can make you quite ill to the point of physical incapacitation (and even death in extreme cases), as airmen we should also be quite concerned by the effects of low-level CO poisoning on our cognitive abilities that affect our performance and judgement as flight crew members. CO poisoning affects cognitive function by interfering with the ability of our red blood cells to carry oxygen to the brain. In short, it produces a form of hypoxia (known tecnically as “hypemic hypoxia”). But we all know that flying in unpressurized aircraft at cabin altitudes well above those to which our bodies are acclimated also causes hypoxia (variously termed “altitude hypoxia” or “hypoxic hypoxia”) which also reduces the supply of oxygen to the brain. Common sense would suggest that the effects of CO-induced hypoxia and altitude-induced hypoxia are cumulative, but very little research has been done on this to date.

(I’m happy to see that the FAA Civil Aeromedical Institude is finally doing a study on this issue, focused specifically on the question on the degree to which pilots who smoke before flight – and thereby subject themselves to mild CO poisioning – have degraded performance at altitude compared to non-smoker pilots. See http://www.cami.jccbi.gov/AAM-500/hypoxia.html)

While we’re waiting for the research results, I’d suggest we apply a common-sense approach to CO in the cockpit. I’d offer the following guidelines:

  1. Cockpit CO concentrations greater than 35 to 50 PPM for period exceeding a few minutes are unacceptable. If such concentrations are observed on the ground and cannot be corrected immediately (see below), don’t take off. If such concentrations are observed in flight, land immediately. (The FAA says 50 PPM, I’d prefer 35 PPM, take your pick.)
  1. The hazard created by low levels of CO contamination in the cockpit rise rapidly at cabin altitudes above 8,000 feet. In my opinion, even concentrations of 10 or 20 PPM should be cause for concern if you’re flying at 11,000 feet. If this occurs, I’d advise you either to descend immediately or to go on oxygen (and use a mask, NOT a cannula).
  1. Many aircraft register significant CO concentrations in the cabin during ground operations. In most cases, this can be substantially reduced by proper engine leaning. As a general rule, aircraft piston engines should NOT be operated at full-rich during ground operations, but should be leaned to the point of maximum RPM rise. Doing so typically results in a precipitous drop in the CO content of engine exhaust. Keep in mind that CO results from INCOMPLETE combustion, and a rich mixture causes incomplete combustion because there’s not enough oxygen to support complete combustion. (Opening cabin air vents and/or turning on ventilation blowers may also help … or may make things worse, depending on the particular aircraft.)
  1. UL-2034-approved CO detectors like the AIM 696 do not register CO concentrations below 35 PPM on their digital readouts. Although some pilots prefer this, I much prefer a highly-sensitive CO monitor that registers concentrations down to 10 PPM or less. Even though very low CO concentrations may not be hazardous – particularly if they occur only during short-lasting phases of flight operation – I would prefer to know about them, and to be able to try things (like opening vents, turning on blowers, leaning the mixture, etc.) to see if they can be reduced or eliminated. But maybe that’s just me.

On another subject, I can confirm that the U.S. company (IST) that acquired AIM (of Canada) last year has indeed announced that they’re getting out of the consumer products business altogether, including discontinuing manufacture of the AIM 696 and 935 products. Aeromedix.com is working hard to fill the void created by the withdrawal of these products, and should have an announcement on this quite soon. Meantime, IST-AIM has committed to honor the warranty on all AIM 696 and 935 units presently in the field.

I would comment that due to to Avweb’s strong recommendation, I purchased the AIM unit. First, it went bad after 9 months. Second, it was very difficult to get a hold of the AIM people. Third, when they said three weeks ago that they would send me a new unit, they haven’t as of yet. Kind of interesting - if the CO detection is so important, you’d think that they would have a sense of urgency to get the new unit to a consumer who bought and paid for one. I love Avweb, and respect Mike Busch’s recommendations. In this case, I can’t say much for AIM!!

17

Mike,

Thanks alot for coming onto the board to help clarify these issues for everyone. It sounds like I need an AIM 696 in addition to my 935; I don’t mind the peep-peep of low level alerts, but I think passengers might find it discomfiting (“Oh, thats just low levels of the poison CO…”). The low-sensitivity detector would be better in those cases.

-Curt

18

Curtis, let me try to put some of this in perspective for you and the other folks on this forum…

First, CO concentration readings of 7-30 PPM are well within the FAA requirements for newly-certified airplanes under FAR Part 23. For certification testing, the FAA requires only that CO concentrations in the cabin do not exceed 50 PPM. I happen to think that standard is way too loose, but that’s what’s in Part 23.

(CAR 3, the predecessor of Part 23 and the rules under which the vast majority of today’s single-engine piston fleet was certified – Bonanzas, Cessnas, Mooneys, Pipers, etc. – had no CO testing requirements at all, so Part 23 is certainly a huge improvement in that regard.)

It’s important to keep in mind that the effects of CO on the bloodstream are a function of two variables: CO concentration (as measured by your CO monitor) and time of exposure. A concentration of 100 PPM of CO is inconsequential if you’re only exposed to it for a minute or two. A concentration of 30 PPM could be highly significant if you were exposed to it for 24 hours.

A third important variable that has not been studied adequately is cabin altitude. Although profound CO poisoning can make you quite ill to the point of physical incapacitation (and even death in extreme cases), as airmen we should also be quite concerned by the effects of low-level CO poisoning on our cognitive abilities that affect our performance and judgement as flight crew members. CO poisoning affects cognitive function by interfering with the ability of our red blood cells to carry oxygen to the brain. In short, it produces a form of hypoxia (known tecnically as “hypemic hypoxia”). But we all know that flying in unpressurized aircraft at cabin altitudes well above those to which our bodies are acclimated also causes hypoxia (variously termed “altitude hypoxia” or “hypoxic hypoxia”) which also reduces the supply of oxygen to the brain. Common sense would suggest that the effects of CO-induced hypoxia and altitude-induced hypoxia are cumulative, but very little research has been done on this to date.

(I’m happy to see that the FAA Civil Aeromedical Institude is finally doing a study on this issue, focused specifically on the question on the degree to which pilots who smoke before flight – and thereby subject themselves to mild CO poisioning – have degraded performance at altitude compared to non-smoker pilots. See http://www.cami.jccbi.gov/AAM-500/hypoxia.html)

While we’re waiting for the research results, I’d suggest we apply a common-sense approach to CO in the cockpit. I’d offer the following guidelines:

  1. Cockpit CO concentrations greater than 35 to 50 PPM for period exceeding a few minutes are unacceptable. If such concentrations are observed on the ground and cannot be corrected immediately (see below), don’t take off. If such concentrations are observed in flight, land immediately. (The FAA says 50 PPM, I’d prefer 35 PPM, take your pick.)
  1. The hazard created by low levels of CO contamination in the cockpit rise rapidly at cabin altitudes above 8,000 feet. In my opinion, even concentrations of 10 or 20 PPM should be cause for concern if you’re flying at 11,000 feet. If this occurs, I’d advise you either to descend immediately or to go on oxygen (and use a mask, NOT a cannula).
  1. Many aircraft register significant CO concentrations in the cabin during ground operations. In most cases, this can be substantially reduced by proper engine leaning. As a general rule, aircraft piston engines should NOT be operated at full-rich during ground operations, but should be leaned to the point of maximum RPM rise. Doing so typically results in a precipitous drop in the CO content of engine exhaust. Keep in mind that CO results from INCOMPLETE combustion, and a rich mixture causes incomplete combustion because there’s not enough oxygen to support complete combustion. (Opening cabin air vents and/or turning on ventilation blowers may also help … or may make things worse, depending on the particular aircraft.)
  1. UL-2034-approved CO detectors like the AIM 696 do not register CO concentrations below 35 PPM on their digital readouts. Although some pilots prefer this, I much prefer a highly-sensitive CO monitor that registers concentrations down to 10 PPM or less. Even though very low CO concentrations may not be hazardous – particularly if they occur only during short-lasting phases of flight operation – I would prefer to know about them, and to be able to try things (like opening vents, turning on blowers, leaning the mixture, etc.) to see if they can be reduced or eliminated. But maybe that’s just me.

On another subject, I can confirm that the U.S. company (IST) that acquired AIM (of Canada) last year has indeed announced that they’re getting out of the consumer products business altogether, including discontinuing manufacture of the AIM 696 and 935 products. Aeromedix.com is working hard to fill the void created by the withdrawal of these products, and should have an announcement on this quite soon. Meantime, IST-AIM has committed to honor the warranty on all AIM 696 and 935 units presently in the field.

Has anyone evaluated a product called CO Guardian? What are the viable alternatives to IST-AIM?

19

Nope, the Cirrus Mike Busch and the AVweb Mike Busch are definitely two distinct entities. I recall bumping into the other Mike Busch at an AOPA Expo a few years back. For about 15 seconds, both of us stared at the other’s exhibitor nametag in disbelief. Then, almost simultaneously, we both broke out laughing.

20

I love Avweb, and respect Mike Busch’s recommendations. In this case, I can’t say much for AIM!!<<

In fairness, Andy, I’d like to point out that at the time I made my recommendations of the AIM 696 and later the AIM 935, AIM was a Canadian company located in Vancouver, B.C. In my judgment, they were an excellent company with an excellent product and outstanding warranty support.

Last year, AIM was acquired by Industrial Sensor Technology (IST) of New York. It is now apparent that IST acquired AIM in order to obtain some of their patented sensor technology. IST had no interest in AIM’s consumer products or customers, and demonstrated it immediately by drastically lengthening delivery times, reducing product quality, and neglecting customer warranty requests. Finally, just a few weeks ago, IST announced what I’m sure they knew all along – that they were getting out of the consumer products business altogether to concentrate exclusively on high-priced industrial sensors. In doing so, they offered their distributors and customers absolutely no warning – their letter was dated April 30, and the termination date was May 1! Cute, eh?

A real shame … AIM (the original Canadian company) was a good outfit with a good product and a good attitude. The same certainly cannot be said for IST-AIM. And while I’m certainly as unhappy as anyone about the acquisition and subsequent dismembering of AIM by IST, I can’t see how I could possibly have forseen this at the time I made my recommendation of the AIM 696 and 935 products.