Anyone have any info on this one?

http://www.youtube.com/watch?v=SqgE12mvw-A

Yikes, that sucker dug in a lot more than I thought it would on the snow. There was hardly more than a touchdown point before it flipped.

I've seen this happen a few times and I've always been curious, those roads don't look crammed with cars, why didn't he set it down on the 4 lane (maybe a wide 2) out there? Or even one of the ranch streets you see in the video. I'd rather risk a car collision with the knowledge I could still land off the road if traffic is bad when you get down there.

This is old news!

Happened up in Logan, UT a year or two ago. Can't remember if it was fuel starvation or plain engine failure...Everyone walked away.

***EDIT*** Just read the NTSB report again and it lists carb ice.

They mentioned 'carb ice', and if that was in fact the culptit, he should have tried re-starting the engine as the ice would most likely have melted after a few minutes via residual engine heat.

I also noticed he did not have any flaps out. I wonder if a slower touchdown speed may have prevented the flip.

Glad they all made it out relatively unscathed.

..........just checked NTSB and it was carb ice. Here is a link.

http://www.ntsb.gov/AviationQuery/brief ... 0430&key=1

This is old news!

Yup. Lots of discussion here when it happened.

Cary

MAU MAU wrote:They mentioned 'carb ice', and if that was in fact the culptit, he should have tried re-starting the engine as the ice would most likely have melted after a few minutes via residual engine heat.1

That comment suggests a fundamental misunderstanding of the dynamics of carb ice.

"Residual engine heat" is very unlikely to melt carb ice. And very shortly after the engine fails, your carb heat system will be useless, as the flow of air through it rapidly cools the exhaust system, which supplies the carb heat. Bear in mind that certification standards only require carb heat to remove "worst case" carb ice at very high engine power.....which may not be available once significant carb ice has formed.

And, even flying into warmer air is unlikely to remove carb ice that's formed. Carb ice CAN form under the right circumstances at temperatures as high as 70 degrees F.

MTV

The comment that ice can form up to 70 deg. is right on, my Ercoupe iced up in cruise twice while I owned it, both times the temp at altitude was in the low 70's, temp on the ground when I took off was over 90 deg. both times. Fortunatly I used heat before it quit completely and it melted out.

mtv wrote:

MAU MAU wrote:They mentioned 'carb ice', and if that was in fact the culptit, he should have tried re-starting the engine as the ice would most likely have melted after a few minutes via residual engine heat.1

That comment suggests a fundamental misunderstanding of the dynamics of carb ice.

"Residual engine heat" is very unlikely to melt carb ice. And very shortly after the engine fails, your carb heat system will be useless, as the flow of air through it rapidly cools the exhaust system, which supplies the carb heat. Bear in mind that certification standards only require carb heat to remove "worst case" carb ice at very high engine power.....which may not be available once significant carb ice has formed.

And, even flying into warmer air is unlikely to remove carb ice that's formed. Carb ice CAN form under the right circumstances at temperatures as high as 70 degrees F.

MTV

After reading the initial post yesterday, and attempting to remember what I learned eons ago about carb ice, I spent a few hours reading numerous articles about this phenomenon.

The articles vary somewhat, but my takeaway is that carb ice can happen at temperatures well above 70 degrees, and that close monitoring of RPM for fixed props and manifold pressure for constant speed props is essential.

It also seems to depend upon where the carburetor is installed on the engine as to whether it is a high risk or low risk ice maker, and for its potential to melt the ice through residual heating.

I am glad this crash post was brought back to life as it got me into research mode which may save my life someday.

This is a pretty good chart--relatively simple to comprehend--and it clearly shows the relationship of temperature and humidity to the probability of carb icing:
http://flighttraining.aopa.org/images/f ... britlg.jpg
Most people are surprised at how high the temp can be and still be conducive to carb icing.

You'd be surprised at how many times a carb heat gauge will show that the incoming air is below freezing--and all it takes is a little moisture in the air, not necessarily visible moisture, to turn that moisture into ice.

One of the things I have preached for a long time is that Piper's "carburetor heat on if required" is a great way of having the engine quit. That same sort of language appears in the Cessna 182 POH for cruise descents. Since most trainers and a whole lot of higher performance carbureted engines don't have carb heat gauges, how will the pilot know when it's "required"? In my view, it's necessary whenever the rpm will be reduced, because that's when the engine heat is less, and the warm air from the carb heat muff is most needed--in other words, for every landing. I like Cessna's language in some POHs: "Carburetor heat should be applied prior to any significant reduction or closing of the throttle" and "apply full heat before closing throttle" in others.

While it's arguable that some carburetor installations are less susceptible to icing than others, why get into that discussion? Why not just add carb heat whenever the throttle is going to be significantly reduced, to make sure? If you're wrong about whether this or that airplane's carburetor is less susceptible to icing and it ices over because you didn't apply carb heat, you don't have any power. If you're right but still apply carb heat, no problem.

Cary

The carb heat on my skylane really works, so much that it will foul plugs between annuals if you use it every time you pull power. I have a decent carb temp guage that seems to be a good indicator. Summer days the morning after a good rain is prime time for my bird.

I have had serious carb ice events three times, ranging from the warmest at 80 degrees OAT and the coldest at 20, and it is no less surprising in either situation. But immediate application of carb heat worked in both cases. Engine initially quits as the water goes in, then picks back up as soon as the water moves through. It should be an ingrained reflex.

And I do know people that have worked on re-routing their air intake and have successfully reduced the incidence of carb ice. I pop my carb heat on periodically through every flight, and haven't had any surprises for over 400 hours now. I don't leave carb heat on for the entire descent if I'm flying over 1500 feet AGL, but I do bring it on periodically in descent, then leave it on from base through final in the pattern.

MTV...are you saying if he immediately applied carb heat when the engine rpm dropped it still wouldn't melt it out? My reading of accident records is that usually people pull on carb heat, the problem gets worse, so they push it in then fly until the crash, rather than leaving carb heat on and waiting for the resumption in engine power. But I didn't see any statement about that in this case.

I know Zane does not like links to other sites, but this topic is too important and the information in the link is very interesting. Pay special attention to Walter Atkinsons comments which start half way down on page 1.

http://maulepilots.org/forums/viewtopic ... ernate+air

MAU MAU wrote:I know Zane does not like links to other sites

Where did you read that?

Also, do you ever wonder who designed the maulepilots.org forum header?

Troy Hamon wrote:MTV...are you saying if he immediately applied carb heat when the engine rpm dropped it still wouldn't melt it out? My reading of accident records is that usually people pull on carb heat, the problem gets worse, so they push it in then fly until the crash, rather than leaving carb heat on and waiting for the resumption in engine power. But I didn't see any statement about that in this case.

Not at all, Troy. My point was simply that the longer one waits to apply carb heat after an ice induced engine failure, the less likely the system is to be able to melt the accumulated ice. I've seen too many pilots, presented with a simulated engine failure in training, wait a looooong time before finally applying carb heat. Many go through the process of finding a potential landing site, slowing to best glide speed, THEN go through restart procedures.

Take a look at the carb heat system on your airplane. There is an air inlet, which flows air into a shroud around some part of the exhaust system, generally the muffler. To prevent overheating the exhaust system, most carb heat systems have a valve which directs the air flowing over the exhaust either into the carb inlet OR dumping that heated air out the bottom of the cowling.

With carb heat selected to "cold" the system is effectively cooling the muffler or other part of the exhaust system, which has one of the toughest job of any part of your airplane.

So, after a carb ice precipitated engine failure, if you delay application of carb heat, the very source of the heat you need to melt that ice is rapidly cooling. In the Lycoming Piston Engine Service School, I was told that the certification standard for carbureted engines was that the carb heat system has to be demonstrated to remove WORST CASE carb icing immediately after the engine was running at 75% power. The longer you wait to apply carb heat, the less residual heat there is remaining in that exhaust system to melt ice.

My point was, and is, the FIRST thing one should do after an in flight engine failure is to initiate restart procedures, including application of carb heat. The one obvious exception to that suggestion would be after an engine failure at very low altitude, where a landing is imminent.

What REALLY precipitated my earlier comment, however, was the suggestion that "residual engine heat" might remove carb heat. I suppose that under some very limited circumstances that COULD happen, but I sure wouldn't bet on it. Remember, as long as that prop is windmilling, the engine is turning over, and thus is inducting air through that carburetor venturi. This flow draws fuel through the Venturi, and the combination of cooling due to the fuel vaporizing and the drop in pressure due to the Venturi effect is what caused the ice to form in the first place. The point is, if the pilot relis on "residual engine heat" to remove that ice, a rapidly cooling engine and continued ice accretion is apt to sorely disappoint.

Sorry for the long response, but this is an important system, and is often not well understood, at least in my experience.

MTV

mtv wrote:

Troy Hamon wrote:MTV...are you saying if he immediately applied carb heat when the engine rpm dropped it still wouldn't melt it out? My reading of accident records is that usually people pull on carb heat, the problem gets worse, so they push it in then fly until the crash, rather than leaving carb heat on and waiting for the resumption in engine power. But I didn't see any statement about that in this case.

Not at all, Troy. My point was simply that the longer one waits to apply carb heat after an ice induced engine failure, the less likely the system is to be able to melt the accumulated ice. I've seen too many pilots, presented with a simulated engine failure in training, wait a looooong time before finally applying carb heat. Many go through the process of finding a potential landing site, slowing to best glide speed, THEN go through restart procedures.

Take a look at the carb heat system on your airplane. There is an air inlet, which flows air into a shroud around some part of the exhaust system, generally the muffler. To prevent overheating the exhaust system, most carb heat systems have a valve which directs the air flowing over the exhaust either into the carb inlet OR dumping that heated air out the bottom of the cowling.

With carb heat selected to "cold" the system is effectively cooling the muffler or other part of the exhaust system, which has one of the toughest job of any part of your airplane.

So, after a carb ice precipitated engine failure, if you delay application of carb heat, the very source of the heat you need to melt that ice is rapidly cooling. In the Lycoming Piston Engine Service School, I was told that the certification standard for carbureted engines was that the carb heat system has to be demonstrated to remove WORST CASE carb icing immediately after the engine was running at 75% power. The longer you wait to apply carb heat, the less residual heat there is remaining in that exhaust system to melt ice.

My point was, and is, the FIRST thing one should do after an in flight engine failure is to initiate restart procedures, including application of carb heat. The one obvious exception to that suggestion would be after an engine failure at very low altitude, where a landing is imminent.

What REALLY precipitated my earlier comment, however, was the suggestion that "residual engine heat" might remove carb heat. I suppose that under some very limited circumstances that COULD happen, but I sure wouldn't bet on it. Remember, as long as that prop is windmilling, the engine is turning over, and thus is inducting air through that carburetor venturi. This flow draws fuel through the Venturi, and the combination of cooling due to the fuel vaporizing and the drop in pressure due to the Venturi effect is what caused the ice to form in the first place. The point is, if the pilot relis on "residual engine heat" to remove that ice, a rapidly cooling engine and continued ice accretion is apt to sorely disappoint.

Sorry for the long response, but this is an important system, and is often not well understood, at least in my experience.

MTV

Great information MTV! I am about to install a graphic engine monitor in my C180, and it includes a carburetor temp probe. I have never used such a system before, but I have a habit of applying carb heat regularly during flight, as I have iced up my carb a few times before. The conditions that carb ice can occur during can be surprising.

Would the idea behind using carb temperature information be to keep the temperature at the probe above freezing if you see it dropping? It seems that the temperature would vary significantly depending on the position along the venturi. There is a boss on the carburetor body for probe installation. I am assuming that this is the location where the temperature drop is the greatest. Do you know anything about this?

The Continental carbutreted engines tend to be more susceptible to carb ice and the 470s in the 180/182 are well known ice makers. Nothing wrong with that, unless you become complacent. Many 180/182 aircraft came equipped with carb inlet temp instuments...it was a factory option.

I don't know exactly where in the carb a temp probe goes, but I doubt you have any choice in where it goes, frankly. That's going to be dictated by the manufacturer.

The Beaver has a "continuous " carb heat system, with a carb temp instrument. After takeoff, you simply adjust carb inlet temp with the carb heat control to a specified number (can't recall if it's +4 or +7C...been a while). Simple solution, and carb ice is a non issue, as long as you keep that inlet temp adjusted properly.

Check your POH....there may be a reference to the instrument and how Cessna wants it operated. If not, try finding someone with a later model.....it was definitely an option on later models. Anyone out there have that section in their POH?

In cruise, no need to worry about unfiltered air (carb heat typically bypasses the induction air filter) since the air at altitude rarely has significant particulate in it. In fact, partial carb heat is one way to even out EGTs on carbureted engines, so you can run LOP.

MTV

Zzz wrote:

MAU MAU wrote:I know Zane does not like links to other sites

Where did you read that?

Some might get that impression from your occasional requests that people put content here instead of links to their already existing blogs.

Full spectrum engine monitors, I am glad the technologies were introduced to me. Would not fly without, they are in my scan and considered essential where I fly (opinion). This little accident video clip confirms this to me personally.

My unsolicited advice; DO NOT FLY AN expensive aircraft without a good set of gauges! Get advice from experienced pilots on how to interpret them. Many times I need to correlate explicit and un-explicit indications to figure out the situation.

rw2 wrote:

Zzz wrote:

MAU MAU wrote:I know Zane does not like links to other sites

Where did you read that?

Some might get that impression from your occasional requests that people put content here instead of links to their already existing blogs.

Hmm perhaps. For the record, links to relevant threads or articles on other sites to complement the discussion is perfectly fine. We love SuperCub.org and maulepilots.org and Shortfield.com and many others.

If someone is starting a new thread that only contains a link to a personal blog, that's another story. Add the content here or at least give us a preview.

I'll update the orientation guide to clear this up.