VIDEO: Beware of Carb Ice and Expired Insurance

[challenger_nami]

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VIDEO: https://youtu.be/JDQVN_G1bM4

Accident Details: https://aviation-safety.net/wikibase/153006

Date: February 2 2013


Beware of Carb Ice and Expired aircraft Insurance policy.

The video shows forced landing attempt of a Cessna after engine failure most likely due to Carburetor Ice.

The pilot attempted an almost successful forced landing in a field covered with deep snow, however, unfortunately the nose gear digs in and the aircraft flips over.

The story has a relatively happy ending. The aircraft had 3 adult and one infant as occupants. All survived and walked away. Only loss of property.

The aircrafts insurance policy had expired the night before, so the insurance company refused to pay the damages.

Who knows, maybe the lack of insurance may have influenced the pilot’s decision to land in the snow covered field instead of the interstate highway.



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[photofly]

Not exactly typical carb ice territory, is it, in million-mile visibility several thousand feet above a landscape cold enough to be completely snow covered?

I’d put my money on something else.

I doubt also that with those passengers on board, the pilot was too concerned in the moment with his insurance situation.

The pilot reported that during a climb to cruise flight, he observed the engine rpm suddenly reduce, and he immediately applied carburetor heat. The pilot stated that the engine rpm increased for about 3 seconds before it decreased again. The pilot began troubleshooting the engine and performing the emergency landing checklist. The pilot stated that when he turned the ignition switch off and back on, the engine backfired once; however, the engine rpm remained at 1,000. He initiated a forced landing to an open, snow-covered field. During the landing roll, the airplane nosed over. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The carburetor was disassembled and examined internally. The carburetor float bowl contained a liquid consistent with fuel, which tested positive for water using water-finding paste.

A local reporting station recorded the temperature at 25 degrees Fahrenheit and dew point at 19 degrees Fahrenheit. The reported weather conditions were conducive to carburetor icing at glide and cruise power. Given the sudden loss of engine rpm before and the rise in engine rpm following the application of carburetor heat, it is likely that carburetor ice was the reason for the loss of engine power.

I’m not buying it. Carb icing so sudden as to suddenly overwhelm an engine at full throttle, With the carb heat applied, in air already well below freezing in clear VMC? I don’t think so. If that were all there is to it, we would have 172s falling out of the sky all over Canada, daily.

I’m not sure what the pre-flight inspection and maintenance practices of a pilot insufficiently diligent to know or care his insurance had expired, but I’m sure there’s more to this.

[challenger_nami]

Not exactly typical carb ice territory, is it, in million-mile visibility several thousand feet above a landscape cold enough to be completely snow covered?

I’d put my money on something else.

I doubt also that with those passengers on board, the pilot was too concerned in the moment with his insurance situation.

Here me again trying to reason with @photofly. Help me lord.

@Photofly,

If you know for a fact that the cause of accident was something else, please enlighten me.

Also, Why don’t you think there can be carburetor icing when there is snow on the ground?



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[photofly]

Not exactly typical carb ice territory, is it, in million-mile visibility several thousand feet above a landscape cold enough to be completely snow covered?

I’d put my money on something else.

I doubt also that with those passengers on board, the pilot was too concerned in the moment with his insurance situation.

Here me again trying to reason with @photofly. Help me lord.

@Photofly, Why would the fact that there was snow on the ground, to you mean you can not develop Carb Ice?






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Ground temperature -4C, dewpoint -7C, colder at altitude and not a cloud in the sky. Would you honestly credit a 172 being suddenly and incurably overwhelmed by carb ice, with the carb heat ON, at full throttle?

Other than “beware”, What would you have done differently to avoid this accident?

[pelmet]

I seem to remember an earlier thread about this accident. Perhaps the NTSB has a final report about it.

[photofly]

I seem to remember an earlier thread about this accident. Perhaps the NTSB has a final report about it.

You’re the man to find it!

[challenger_nami]

Ground temperature -4C, dewpoint -7C, colder at altitude and not a cloud in the sky. Would you honestly credit a 172 being overwhelmed by carb ice, with the carb heat ON, at full throttle?

Ground temperature -4C, dewpoint -7C, colder at altitude and not a cloud in the sky

Temperature, Dew Point is close ... within 3 degrees. The temperature is not always colder at altitude. Do you know what INVERSION is? Do you know/remember what Warm Air Aloft means?

You say: Not A Cloud in the Sky??????
Look at the attached image taken from 2’50” of the video. You can clearly see the visible moisture in the air ... do you not see the Mist?

Other than “beware”, What would you have done differently to avoid this accident

Carb ice is like cancer for your engine:
if you detect it early enough, you can treat it easily with Carb Heat and some added RPM. If you let it progress and build up, It will kill your engine. Ask the pilot in this video and he’ll tell you.


When the conditions for carb ice are present, as they are here, I would maintain a higher RPM than normal and apply carb heat regularly to check for symptoms of Carb ice.

[photofly]

I see the mist on the ground. But the loss of power didn't happen on the ground. Here's the view from the beginning of the video, after the descent had begun:

Screen Shot 2020-11-11 at 8.29.16 AM.png (1.14 MiB) Viewed 1680 times

Not exactly marginal VMC.

[photofly]

For reference, here is what the NTSB has:
https://www.ntsb.gov/_layouts/NTSB/Open ... Master.PDF


https://www.ntsb.gov/_layouts/NTSB/Open ... dacted.PDF

https://www.ntsb.gov/_layouts/NTSB/Open ... Master.PDF

https://www.ntsb.gov/_layouts/NTSB/Open ... dacted.PDF

[photofly]

From the pilot's report:

"All of this flilght was between 5500 and 6500 ft. We then decided to fly over the Wellsvillle mountains and stared climbing to the North. At about Mendon we turned 180° and flew south. We followed the highway up the canyon just past Sherwood Hills @8500ft when the engine RPM's suddenly dropped. I immediately pulled on the carb heat and the RPMs came back up for approx 3 seconds then dropped again."

[photofly]

From the pilot's report:

"All of this flilght was between 5500 and 6500 ft. We then decided to fly over the Wellsvillle mountains and stared climbing to the North. At about Mendon we turned 180° and flew south. We followed the highway up the canyon just past Sherwood Hills @8500ft when the engine RPM's suddenly dropped. I immediately pulled on the carb heat and the RPMs came back up for approx 3 seconds then dropped again."

The accident was at 2050z. I just pulled the Salt Lake City radiosonde data for 00z on the 14th Feb 2013 - three hours after. (The balloon release is 60 miles from the landing site.) Temperature and dewpoint at 1426 metres above the balloon release (that would be about 9000 feet msl) were measured at +1C and -5C respectively. At 12z on the 13th (9 hours prior) at the same approximate altitude, -3.3C and -8C. So that does put you in carb icing territory, just about, in cruise flight, as reported.

So I guess we conclude the pilot missed the early signs, and although the rpm drop was "sudden" when the situation became critical, he could have prevented this earlier.

Well done, challenger_nami, and thanks for the opportunity to read up about this accident.

[challenger_nami]

From the pilot's report:

"All of this flilght was between 5500 and 6500 ft. We then decided to fly over the Wellsvillle mountains and stared climbing to the North. At about Mendon we turned 180° and flew south. We followed the highway up the canyon just past Sherwood Hills @8500ft when the engine RPM's suddenly dropped. I immediately pulled on the carb heat and the RPMs came back up for approx 3 seconds then dropped again."

The accident was at 2050z. I just pulled the Salt Lake City radiosonde data for 00z on the 14th Feb 2013 - three hours after. (The balloon release is 60 miles from the landing site.) Temperature and dewpoint at 1426 metres above the balloon release (that would be about 9000 feet msl) were measured at +1C and -5C respectively. At 12z on the 13th (9 hours prior) at the same approximate altitude, -3.3C and -8C. So that does put you in carb icing territory, just about, in cruise flight, as reported.

So I guess we conclude the pilot missed the early signs, and although the rpm drop was "sudden" when the situation became critical, he could have prevented this earlier.

Well done, challenger_nami, and thanks for the opportunity to read up about this accident.

Thank you for your contribution to the topic my friend.





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[PT6-114A]

“The carburetor float bowl contained a liquid consistent with fuel, which tested positive for water using water-finding paste.”

If there was water in the fuel plus the atmosphere was right for ice sounds like the perfect storm for carb ice.

[digits_]

So assuming it was carb ice, what could the pilot have done differently?

If the carb heat on resulted in an RPM increase, that means the engine was still running, and thus carb heat was operational. If that still resulted in power loss, what could he have done differently?

[CpnCrunch]

This was a 175, not a 172. It has a continental engine, so is more prone to carb ice like the early 172s. Lycoming 172s almost never get carb ice.

I almost always get carb ice in conditions like that (temperature inversion and a hazy layer) if temp is below about 10C in the C150. Usually it clears up, but sometimes you need to reduce throttle (if using full throttle) to get a smooth running engine. Generally just adjusting throttle and mixture should clear things up if you're diligent about using carb heat *immediately* you hear any change in engine tone. If you let things go on for too long, who knows...it will probably take a long time to clear up. If it's got to the point where you're only getting 1000rpm, well, I don't think there's much hope, as your engine isn't going to be generating much heat.

It could be his carb heat box was faulty. If you don't get an rpm drop when applying carb heat during the runup, don't fly. There was an accident here where a lycoming 172 landed in a field due to carb ice, and it was found that the carburettor heat ducting had become disconnected from the carburettor box.

[photofly]

“The carburetor float bowl contained a liquid consistent with fuel, which tested positive for water using water-finding paste.”

This is something not really explored. I'm not seeing how water can get into the float bowl from the venturi, so that bit reads like there was contaminated fuel. But why no issues until 8500 was reached? Perhaps with the ground temperature below freezing there was water ice at the bottom of the fuel tank(s) at takeoff, then (it could have been just above freezing at their altitude, looking at the radiosonde data) after reaching that altitude it melted, and entered the carburetor, causing the power loss.

The reporting from the pilot is less than ideal (not being critical, the guy had just totalled his airplane after all) but he doesn't make any distinction between a sudden drop in RPM and a total power loss - or when in the sequence that happened. He doesn't refer to any prior warning signs of carb icing issues, either, unsurprisingly, so perhaps he missed them, or carb icing wasn't the whole story.

Sometimes things remain a mystery.

[rookiepilot]

Lean, baby lean....not saying it would have made a difference here though....

[Cliff Jumper]

so that bit reads like there was contaminated fuel. But why no issues until 8500 was reached?

Perhaps pitch had something to do with the water shifting around in the tank? Did he level off at 8500?

Edited... maybe not, seems he was level at 5500 before.