It happened today for only the second time in 40 years of flying, but as I was toodling through the sky in the Cub today, the engine started running just a little rough, then it transitioned to really rough in just a few seconds. I pulled the carb heat and it cleared up within seconds.
Overcast skies with temps about 40 degrees F and very high humidity. Clouds were at about 2,000 feet and I might not have had the full separation that's called for in the FAR's, but I wasn't skimming the bottoms either.
The only other time I've experienced carb ice at cruise was years ago in an Ercoupe. Hot summer day, lots of humidity, cruising below some big cumulus clouds. Engine almost quit it came on so quickly. Carb heat cleared it up very quickly. I put the carb heat back to cold and it immediately started to stumble again. The answer that day and today was to continue the flight with full carb heat to ensure that no more ice accumulated.
Very different days, but very high humidity was the common feature both days.
I know folks who've never experienced carb ice and I think we tend to think that the carb heat handle is only used during primary training and/or in the traffic pattern in anticipation of a low power setting. Just wanted to post this reminder that carb ice can occur at normal cruise power under the right combination of temperature and high humidity. When you do your pre-flight run-up, please make sure your carb heat really works and then remember to use it ASAP in the event your engine ever starts to unexpectedly lose power.
Overcast skies with temps about 40 degrees F and very high humidity. Clouds were at about 2,000 feet and I might not have had the full separation that's called for in the FAR's, but I wasn't skimming the bottoms either.
The only other time I've experienced carb ice at cruise was years ago in an Ercoupe. Hot summer day, lots of humidity, cruising below some big cumulus clouds. Engine almost quit it came on so quickly. Carb heat cleared it up very quickly. I put the carb heat back to cold and it immediately started to stumble again. The answer that day and today was to continue the flight with full carb heat to ensure that no more ice accumulated.
Very different days, but very high humidity was the common feature both days.
I know folks who've never experienced carb ice and I think we tend to think that the carb heat handle is only used during primary training and/or in the traffic pattern in anticipation of a low power setting. Just wanted to post this reminder that carb ice can occur at normal cruise power under the right combination of temperature and high humidity. When you do your pre-flight run-up, please make sure your carb heat really works and then remember to use it ASAP in the event your engine ever starts to unexpectedly lose power.
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